While the tried and true method of splashing down in the ocean seems like a reasonable first effort for landing the dragon spacecraft, watching the difficulty the boats have in reaching the spacecraft (the hosts of the stream mentioned it takes them 2 hours!), and the difficulty the SpaceX team had in getting reasonable weather conditions for this test, it seems to me that a propulsive land-based landing would still be a reasonable future improvement to pursue.
If you were the astronaut and it was an emergency that triggered the abort (e.g. the launch vehicle blew up like the Falcon 9 just did), would you really prefer the Dragon tried to land instead of at sea?
Keep in mind it wouldn't be able to choose its landing site either.
As I replied elsewhere, for an abort, a water landing definitely makes sense (and is likely the only reasonable option). I was merely commenting on how drawn out the recovery process is after splashdown, which I would assume would be less time-consuming with a land landing.
That would require significantly more fuel and a different design, likely limiting the Dragon's crew payload.
This abort happened after the rocket reached max Q (highest dynamic pressure) when it was flying East (and still upward, but to get to orbit you must fly sideways over water). Returning West to get back over land would be fuel prohibitive on a fully loaded crew capsule.
The reusable falcon 9 stages have almost nothing in them when they fly back to land.
For an abort, a water landing definitely makes sense. Perhaps there is no way to avoid the tough weather requirements for the downrange abort. The lengthy recovery time still seems due to the water landing, however. I wonder if it will be a 2 hour recovery time during normal water landing?
I still wonder how much more difficult it is to get proper weather conditions over open sea vs. land when preparing to land during a normal flight. I'd imagine strong winds become stronger over sea than over land, and of course, the ability for ships to reach you in choppy seas becomes much more difficult.
That was the original end plan, but AFAIK it was mixed a couple of years ago.
“The reason we decided not to pursue (powered landings) heavily is it would have taken a tremendous amount of effort to qualify that for safety, particularly for crew transport,” Musk said. “And then there was a time when I thought that the Dragon approach to landing on Mars, where you’ve got a base heat shield and side-mounted thrusters, would be the right way to land on Mars, but now I’m pretty confident that is not the right way, and that there’s a far better approach.” [0]
To be clear, propulsively landing after an abort was never planned -- you've already used up the fuel doing the abort. Plus, depending on when you abort, you could be half-way across the Atlantic.
Do you know if they had a path for redundancy for a propulsive abort? With 4 parachutes, they likely have the design able to handle a single 'chute failure. Not sure what would be involved with single failures on the propulsive abort but that may have been a large contributor to go with the required return fuel.
The abort is the redundancy... ;-) I'm not sure what specifically you are thinking about, but in general since an abort is already one critical fault away from the nominal case, I believe the requirements for redundancy are lower.
Just thinking this through, because I'm more familiar with airplanes than manned rockets:
The design has 4 parachutes, likely for packaging and design constraints, but also provide some level of redundancy.
My comment wasn't clear now that I re-read it, but if you use a propulsive landing after a propulsive abort, you'd need additional fuel. If you remove the parachutes, that weight could then be used for landing fuel, but fuel weight may still exceed that. I haven't run the numbers.
The aborted dragon, after leaving Falcon, is now a self-contained vehicle carrying multiple people. It is a redundant and failsafe safety part of the entire system, but it's hard for me to believe it would be designed with everything having to work perfectly after an abort in order to safely return the occupants. Guidance and Control, life support, propulsion...
I'm mainly wondering if you were aware of the systems they would have in place on a propulsive return.
It seems that the amount of fuel to return all the way downrange back to land on a propulsive abort would be more than the parachute weight, which forces a water landing. And since you already design the capsule for carrying those parachutes, you might as well use them on a normal landing as well. That cuts down on additional weight for an abort return. I also don't know that if you have a successful launch, that you have enough reserve from un-used launch abort fuel to then land the capsule without chutes. Seems unlikely, especially with needing failsafe/redundancy.
The Superdracos are powerful engines but they don't have anything near the delta-v to always return to land after an abort even if you fill the entire Dragon with propellant. So you'd always need the chutes anyway.
One additional issue with propulsive lsnding is that you need legs, and they need to penetrate the heat shield. This significantly complicates and weakens an absolutely critical part.
> The Superdracos are powerful engines but they don't have anything near the delta-v to always return to land after an abort even if you fill the entire Dragon with propellant. So you'd always need the chutes anyway.
Not sure that's true. The chutes bring the speed of the capsule down quite a bit, just a short burst of the dracos at the last few feet could allow it to softly land and wouldn't require much propellant. This is exactly what the Soyuz does. My guess is that this approach was rejected by NASA (not SpaceX) due to complexity rather than feasibility.
This is what's referred to in some circles as a "suicide burn"; in that you wait until the absolute last second, then ignite the engines at full throttle to zero out velocity. Assuming the engines work, it's very efficent as you're not accruing what's called "gravity drag" as the velocity goes to zero very rapidly and you're not fighting 9.8m/s acceleration.
If the engines don't start, or you don't get the predicted thrust out of them, well, that's why it's called a suicide burn.
> If the engines don't start, or you don't get the predicted thrust out of them, well, that's why it's called a suicide burn.
Fair enough, but this is exactly what the Soyuz has done for decades, and NASA (as well as Roscosmos) found the approach to be acceptable for human spaceflight. It may introduce complications, but it's clear that it's doable.
Thats why you have the team who tracks the capsule by plane, they jump out with a raft that can survive several days on rough waters. The capsule is pretty sturdy I assume to stay in for some time.
Scott Manley's latest video ( https://www.youtube.com/watch?v=R-HOQrinzlY ) says the capsule should be able to survive in the water for at least 24 hours at minimum, but probably longer.
I think you misunderstood the announcer - the recovery takes 2 hours, but that's not how long it takes the boats to get to the capsule at its splashdown location.
The boats get there pretty quickly.
The time required is for safety checks and so on - there's some pretty nasty materials involved in those thruster engines, and all that stuff has to be checked first.
Interesting, so given this do you think that a normal landing would not have as long of a recovery time, given that it won't use those thruster engines?
In addition to this. The Air Force has personnel that can jump out of the plane with flotation, medical equipment and food in order to survive for an extended period of time on the ocean while it may take a few hours to get fast boats and recovery teams there.
NASA didn't require it. There was an early plan at SpaceX to have Crew Dragon land propulsivly, but they didn't pursue it in favor of developing Starship and SuperHeavy faster. That's what Musk said in an interview some time ago.
I remember that. It still seems to make sense to research propulsive landings and gain NASA's approval for them eventually (while maintaining the well-proven water landing capability) if it would cut costs significantly.
From what I remember, after Dragon2 is approved by NASA, all development efforts of SpaceX will be focused on Starship and Super Heavy only.
Dragon2 is no use in the efforts to build a city on Mars. And even for a Moon colony, its too small. Its just there to earn money from flying people to the ISS and back. And for that its already good enough.
Boeing's Starliner lands on solid ground after a normal mission while SpaceX's Dragon lands in the ocean. But that's not relevant to an in-flight abort. Any abort at this stage in the launch (whether Boeing or SpaceX) has to come down over water. That's simply where the trajectory of the launch goes.
As I replied elsewhere, for an abort, a water landing definitely makes sense (and is likely the only reasonable option). I was merely commenting on how drawn out the recovery process is after splashdown, which I would assume would be less time-consuming with a land landing.
In the introduction of the space-x launch broadcast, they mention that in real aborts, military will be involved.
With helicopters, rescue personnel will be dropped of.
Also there, it still takes a while for boats to arrive.
My understanding is, that the Nasa didn't like the idea of propulsive landing. As the dragon capsule is purely for supporting the ISS, SpaceX has no incentive to spend money on anything they are not using for the Nasa missions.
For everything else, they are developing the Starship. If that program goes as planned, the dragon capsule will be used only for a short time, I guess.
Why not? It didn't take that long to certify Dragon, and most of the delays were on SpaceX (like blowing up the capsule they were originally intending to use for this test).
I believe SpaceX isn't working with NASA to get Starship human rated by them. I think they are trying to do it 100% private, partially so they don't need to prove it to NASA's standards.
Interestingly, in the press conference, Musk mentioned that SpaceX would like to try to catch spacecraft, which I would think would reduce some of the water landing costs.
> watching the difficulty the boats have in reaching the spacecraft (the hosts of the stream mentioned it takes them 2 hours!)
From my understanding, the host meant that getting the dragon and crew back to the shore would take 2 hours, not the recovery boat to get to them. They could probably even have helicopters around the area which could fly and pick the dragon up.
At the press conference Elon said that all remaining tests are expected to be finished by the end of Q1 2020 and the first flight is expected to launch in Q2. Of course they have to analyze the data from today's test.
Also the flight can be delayed if NASA decides to extend astronauts' time on ISS which would require additional training for them.
The pointed nosecone on the top of the rocket came off and it lost aerodynamic stability, and started to tumble. The tumbling caused the fuel and oxydizer to slosh around the very thin (and lightweight) tanks that are not designed with withstand that kind of force. The sloshing accelerated the tumbling. The thin tanks rupture causing the fuel and oxidizer to mix in the vicinity of a lit rocket engine. BOOM.
Given the velocity it was going the capsule popping off the top basically turned the rest of the rocket into a supersonic flying brick. The amount of drag would be enormous and the rest of the ship basically just tore itself apart. As soon as the oxidizer and fuel combined in the crumbing mess you get a big explosion.
That was all expected to happen and why they launch these things out over the ocean. These rockets also usually have a self-destruct mechanism that a range safety officer can trigger if the rocket starts coming back towards land.
Based on what they said, I'm assuming that it would have been triggered at some point before it started coming down, but they were expecting that it would be destroyed before that happened.
The upper stage hit the ocean intact. That suggests the FTS was not triggered (or it was triggered and failed to destroy the stage, which would be more concerning)
Falcon 9 doesn't use an FTS manually triggered by an RSO. It uses an AFTS, which is controlled by the rocket itself.
My guess is it was armed for the early stages of the flight (when there was still a risk something could go seriously wrong and the rocket could start heading towards Orlandit), but it was disarmed (or just given very generous parameters) once the rocket was downrange a ways.
At some point there must have been a mission design meeting for this test where they decided on fuel levels in the booster. Just as much as needed to get to max Q? Just like a real launch that would put the capsule into orbit and land the booster? Something in between that creates a nice fireball but not too wasteful?
(and on an entirely unrelated note, I really hate watching those parachutes bounce off each other. I know it must be perfectly safe or else it wouldn't have been the unquestioned method off choice for at least half a century, but it looks so uncontrolled it gives me nausea)
You want to test this stuff as realistically as possible. Changing the amount of fuel means changing launch weight which means (presumably) changes in throttle profile etc. The control systems are also probably designed with a certain weight to reach orbit so it's possible that an unusually light rocket would be unstable.
I'm not sure whether this would actually make a difference, but if you know it works at nominal fuel weight then you have some confidence it would work during a real launch.
There are pictures of the second stage coming down in one piece and exploding upon hitting the water (at a safe distance away from the capsule and recovery crews). So it certainly doesn't look like the flight termination system was engaged.
The SpaceX FTS should be fully-automated per this test. It is one criteria that still needs to be certified for the commercial crew program. That entire sequence should have been performed automatically by a computer (throttle back->fire abort rockets->terminate stage 1 booster).
I suspect the FTS was appropriately triggered and that the 2nd stage simply survived the initial carnage via happenstance or potentially unintentionally due to changes in the structure regarding the missing front piece.
CRS-7 started as a failure of the second stage, at much higher altitude. The cloud of gas from the ruptured upper stage tanks would have obscured much of what was going on with the booster.
It was a very different "failure", which would naturally look different.
The overpressure from the burst helium COPV ruptured the second-stage tanks and spilled the contents. We didn't really see clouds of unburnt fluids or gases this time, it was an explosion right from the start. That's what I meant when I said it looked different this time.
Yes, I actually meant to say that the sudden explosion did not look like CRS-7 which had this spilling-a-dewar look and guessed that the AFTS might have been involved. It was really nothing more than a wild guess.
It was intended to be disposed of this way. I too wonder whether it was demolished by way of explosion, or if SpaceX instead used this opportunity to see what a non-optimal flight pattern would do to the structure ..
In addition to the loss of the aerodynamic nose, it also started tumbling simply because the engines were powered off. Modern rockets, falcon 9 included, are not actually aerodynamically stable during flight, and rely on active controls from gimballing the engines to keep pointed in the right direction. Once the engines power down, the rocket has little chance of surviving.
Podcast recommendation for all german speakers here.
Tim Pritlove recently interviewed Hans Koenigsmann (Engineer and Vice President of Mission Assurance at SpaceX since 2011). The episode was released two days ago. They talk about the history of Space X and the future planes (Mars mission and Starlink).
Its part of the Podcast "Raumzeit".
It looks good so far but we won't really know until the telemetry has been looked at. For example the g-forces on the astronauts could have exceeded the safe limits.
We’re here to discuss the latest Musk-backed company’s achievement. There’s a huge interest in all things Musk. To the point that everything he does seems widely related - I mean how many people here are rooting for his dream of a Mars colony? So I asked whether it could affect another Musk company. It’s related.
You asked if it could "impact" the stock which is commonly understood as meaning a downward impact. Even setting aside the fact that they are different companies, I don't see how a successful demonstration could do that, no. If anything, if you want to make it about Musk and not the specific companies, it should give people more confidence in Musk since it went exactly as planned.
Impact per google: “2. have a strong effect on someone or something” No indication of direction. Lacking this distinction, the direction is implicit from a successful test to be positive.
The explosion was unexpected so either they will have to fix what went wrong there, which in turn will possibly effect the design which would then most likely need another flight test if you want to be safe enough or they will let it be as is which would be unsafe?
They expected the splashdown to happen several seconds later than it did. This could mean the capsule was going faster than it should have before its parachute deploy or it didn't slow down enough when hitting the water which would be worse.
Finally the main parachutes where touching each other pretty aggressively it wouldn't seem than unfathomable that two or more of them get tangled up, I don't think there is a backup solution for if that happens.
The explosion was fine and expected. They mentioned this in the livestream, although it looks like the FTS and not aerodynamic forces. Either way, it happened after the capsule was well clear.
Regarding splashdown timing, we will see. They've been testing this extensively in the background, and parachutes have been a pain point all around.
The explosion seemed very much like a controlled detonation and not a breakdown of the rocket as it falls through the atmosphere as was mentioned in the livestream so it seemed like an unplanned or unexpected explosion.
It is insane how willfully someone with over 20k karma points on HN ignores the details of what I'm referring to (the manner in which it exploded not that it exploded) and bluntly assumes the dumbest thing possible about a somewhat neutral statement.
You wrote a very poorly structured, punctuation-less, run-on sentence in the GP comment.
You did so again here.
In both instances it is unclear what you're trying to convey.
Coupled with taking a neutral comment personally, the simplest conclusion to make is that you're not writing for the benefit of anyone else, besides yourself.
Language's primary function is to communicate information. Our minds are like compilers that translate human-readable language into simplified neural impulses. If you write code with poor syntax, the human mind will still compile it, but you're going to get a lot of unexpected behavior, i.e "what the fuck is this guy trying to convey?"
I _think_ what you're getting at is that the flight termination system triggered (controlled explosion) but not when it should have (unplanned)?
As far as I understand it once the capsule ejected the Falcon 9 was destinated to break up (due to aerodynamic forces) and that break up would trigger the FTS automatically. So the AFTS triggering was part of the plan.
That said it also doesn't really matter - the test was about what happens to the capsule when something goes wrong and not what happens to the booster.
You have a bunch of rocket fuel and a very hot rocket engine in close proximity when the booster starts to break apart. The explosion was entirely expected.
I also have no idea what an unplanned or unexpected controlled detonation looks like. It seems like a controlled explosion has to be planned or expected by definition?
I'm not sure what argument you're trying to make, on the one hand you say the explosion looked like a controlled detonation, on the other that it seems unplanned.
Like others have pointed out: as far as F9 was concerned, the test ended when Dragon detached. Whatever happened after that point is immaterial to the test, so to start saying that would require a reflight is nonsense.
The plan was an explosion due to free-fall and atmospheric forces. The plan was not for an explosion due to a controlled detonation. I hope you are able to delineate between the two and not do a cursory reading of my comment again.
> so to start saying that would require a reflight is nonsense
I said "most likely" and "if you want to be safe enough" I'm not sure why you assumed I meant "require"
Because you also said "... or they will let it be as is which would be unsafe?"
I think your reception here would be better if you dropped the attitude and recognized that your comment used pure speculation to imply that the outcome of the test was negative. Maybe that was not your intent, but then you should have asked more open-ended questions rather than slant them so obviously negatively.
> The plan was not for an explosion due to a controlled detonation.
What evidence do you have that it was a "controlled detonation"? Seems like you're making baseless assumptions and then getting upset when people don't understand what you're trying to say.
When rockets, full of liquid oxygen and propellant, start to break apart in the atmosphere they pretty quickly look like a an explosion.
A rocket with no nosecone will basically lose structural integrity very, very quickly. A rocket 'breaking down' doesn't look like fluttering bits and bobs raining down, it looks like a big fireball.
This makes sense. From footage of past explosions when the booster disintegrates, it's usually falling down. That's why I thought it was unexpected that it just blew up so quickly after the capsule was jettisoned.
It raises the question if the explosion was trigged by the self-destruct sequence and not as mentioned on the livestream by disintegration due to free-fall and aerodynamic forces, did the explosion happen too close to the capsule so as it might have adverse effects on the capsule?
The explosion was not triggered by the self destruct system as has been pointed out to you repeatedly, and even if it were the system has been designed to work correctly in that scenario too (this is covered in the press conference).
The system is designed to be able to abort from a deflagrating rocket without warning (although that was not the design of today's test, obviously). Today, Dragon was already well clear when the stage disintegrated 11s after the abort. Just eyeballing the footage, it's probably a km away.
Thanks for pointing that, it's obvious now that you say it. The next question is why didn't they just explode booster using the self-destruct sequence while the capsule is still attached to test a more realistic scenario?
The Falcon 9 has an AFTS (Automatic Flight Termination System) that destroys the booster if it veers off course (which might take other parameters into account as well?) to avoid damage on ground.
As far as I know the AFTS consists of a detonating cord that runs along the tanks for fuel and oxidizer and rips them open when triggered. The substances mix and deflagrate and only the massive parts will actually reach ground (or sea).
It is confirmed that it was due to the aerodynamic load. Without a nosecone, the craft decelerates hard. The fuel sloshes towards the front of the tanks, ruptures them, then explodes. It all happens very fast.
> They expected the splashdown to happen several seconds later than it did. This could mean the capsule was going faster than it should have before its parachute deploy or it didn't slow down enough when hitting the water which would be worse.
While you can control for variables greatly when you're flying under an engine, I'd imagine it's not so easy to control for environmental variables (such as local variations in wind speed) when you're landing under parachutes. It probably would have been safer for the broadcasters to have had an estimated time of landing with a +/- 20 or so seconds on the display, but I personally doubt landing a little sooner than expected will be a major concern.
Congratulations to the SpaceX and the whole team! That moment of truth when the thrust was lost and the module separated was actually way faster than I had expected. I could barely notice the exhaust plume was smaller and the dragon had already left.
I think it's incredibly satisfying to note that SpaceX is so good at the launch sequence with the Falcon 9 that there were zero delays except weather. With any new rocket system test, I completely expect there to be multiple delays with the countdown.
I was also amazed by this until I watched the post press conference. Elon seemed to describe in an answer to Everyday Astronaut that the launch abort sequence was set to trigger at a specific speed/altitude and that it was the abort program that told the engines to shut down. I would like to see that clarified further but I watched that segment twice and it seems that the abort system was in control, and step 1 was shut down the main engine, step 2 - pressurize/start the abort engines, and so on.
That also could mean, while the abort system said "shut down", the thing that said "get away" was not directly connected, but still using sensor/telemetry inputs as the decision maker.
Also, I'm really interested in knowing if the fireball was performed by the automated abort system.
I would love these to be the answer, so looking forward to clarification.
That is my question too, if the abort system just went "Step 1, Step 2, etc." or if the abort system went "Step 1" and the automated processes took over from there. It wasn't entirely clear but it felt like the first one which is why I watched it again.
As for the fireball, from the press conference I got the sense that the fireball was not triggered manually, that the rocket just broke up.
1) the Dragon initiated the F5 booster shutdown when its sensors detected that it had reached the pre-programmed abort velocity
2) the Dragon initiated the escape according to the abort sequence, not by ground command
3) the fireball was initiated by structural failure as the F5 broke up due to aerodynamic forces, not by the range safety destruct.
4) All of these abort sequence actions were explained in SpaceX's live stream.
Minor nitpick about point 3. John Insprucker said around 13:40 in the stream: "our simulation show that the Falcon will likely break apart due to the tumbling, instead of having the destruct system triggered and destroying the rocket." So what you wrote at point 3 is only likely, but not certain. (Unless of course you know from some source, that they have confirmed the sequence of events since.)
Well point 3 means it didn’t have a blow up at time Y feature. If there was no plan to blow it up and simulations said it would likely blow up, isn’t a pretty safe conclusion that predicated explosion happened?
If the flight termination system had been activated, the upper stage would have been unzipped by the same detonation cord. Since it hit the ocean intact we can presume the FTS was not activated.
>Also, I'm really interested in knowing if the fireball was performed by the automated abort system.
No, that was the rocket breaking up and exploding. If the range safety system had triggered, it would have blown up the second stage, which flew off and crashed into the ocean in a massive explosion
The capsule controlled the abort. It shuts down the main engines then lights it own engines. These things aren't instant, it takes a second to spin up turbo pumps and get fuel flowing and for the fuel in the lines of the main engine to flow out after it sends the signal - that's why the rocket exhaust was still burning as the abort system lit up.
You are most likely concerned that this is more controlled than an actual emergency would look like?
It might not necessarily be an issue. The steps took only split-seconds anyways from what it sounds. Shutting down the main engines helps to escape but appears to not be required for a successful abort. The order might be required though (e.g. the commands need to be sent before the connection between the vehicles is severed) or just beneficial (maybe to give the turbo-pumps of the main engiens a few more moments to spin down already).
You would have one system trigger the simulated failure and another system trigger the abort sequence independently of the trigger system. If it's the same system that triggered the abort and activated the abort sequence after then you can only say that you have tested the abort sequence and not the abort sequence trigger.
They didn't know for sure when the abort would happen. It sounded as if they only tuned thresholds for parameters down to such low values that an abort would be triggered around maximum dynamic pressure (Max Q).
One thing that is clear is that the phrase of launching American astronauts on American rockets from American soil will be used. Multiple times. That's as sure as SpaceX livestream hosts using the formulation 'Historic' Launch Complex 39A ;)
All smiles at the press conference, so seems like things went well.
Elon says, Hardware for first launch will be ready end of Feb, but lots of double checks have to happen before launch and schedules lined up for ISS. Expect launch to happen in 2Q.
Elon adds that they need to get the space craftback and check it over to make sure all is well and there is nothing to address.
Elon teases trying to catch the dragon on re-entry to remove some of the constraints a splash down imposes.
> Elon teases trying to catch the dragon on re-entry
Worth remembering the Crew Dragon wouldn't need a major redesign to do a powered landing. That's one of the reasons why the escape system uses liquid fuel - it needs to be throttlable - instead of a simpler solid fuel design.
I've noticed its only "Historic" Launch Complex 39A, when SpaceX is doing something that could be considered "Historic", for every day SpaceX Launches they seem to revert back to it just being "Launch Complex 39A"
For some years, it was "historic" because the Space Shuttle program ended in 2011, and it wasn't being used for anything. Now 39A is leased by Space-X.
39B is going be used by NASA's Space Launch System. Boeing finally shipped a booster last week.
It was somewhat eerie to hear the “stage 1 throttle up” then abort just after that.. reminded me of the “go for throttle up”.. some of you may know what I’m taking about.. I’m glad these guys will have an abort system available and testing in flight like this was awesome.. good job spaceX
For anyone unfamiliar: "go at throttle up" was the final communication to/from Space Shuttle Challenger during launch of mission STS-51-L moments before it tragically exploded, resulting in the loss of all crew. The Space Shuttle did not have a launch abort system.
ICES was not a launch abort system. It was a way for the astronauts to bail out of the shuttle after re-entry if they weren’t going to be able to land the shuttle safely.
The only shuttle to ever was anything resembling a launch abort system were the first few flights of Columbia. It had ejection seats for the pilot and commander. However, later statements by NASA and the astronauts said that using them probably would’ve resulted in the death of the astronauts due to descending through the extremely hot exhaust of the launch.
The key events of the disaster took place over about three seconds.
A leak of high-temperature gas in the right solid rocket booster damaged the external stack of solid rocket boosters and external fuel tank.
The damage to the external tank caused it to come apart, and resulted in a fireball from the released liquid oxygen and hydrogen. The solid rocket boosters broke free of their mountings as the disaster unfolded.
The Challenger orbiter momentarily survived both the fireball and external tank failure. But those events made it impossible to keep the orbiter correctly oriented.
The loss of proper orientation while travelling ~1000mph meant Challenger was hit with very high stress forces, far beyond anything it was designed to survive, and swiftly broke apart.
Shortly afterward, the Range Safety Officer remotely detonated both solid rocket boosters, which had survived the disaster mostly intact and were careening out of control.
IIRC the word "explosion" has a very specific meaning in this context. I remember reading that the SpaceX AMOS-6 failure was specifically NOT an explosion even though it really looked like one to a layperson.
I watched the Chris Hadfield Masterclass on being an astronaut. It is wonderful and he is a fantastic speaker and lecturer. He talked about the actual launch, how nothing is left for chance, and how every second is accounted for. The astronauts need to fight the effects of the incredible acceleration and have a plan for literally every second until they reach space on 7-8 mins. The MasterClass itself is great, totally worth it and Chris Hadfield is a delight.
My jaw drops every time I hear about SpaceX and Tesla. How could Elon grasp two extremely different and difficult technologies and build such amazing companies within a decade. I have difficulty learning new things. Some pointers will help. Thank you.
Idolization of others is unbecoming period. No person is special or mystically above others for doing acts of business and technology. That's what I live by at least.
Admiring the accomplishments of others is unbecoming? That is remarkably sad.
As the root post says, it is amazing what Musk has achieved, and I'd love to learn what the secret is. I suspect it's that he knows the limits of his own capabilities so he finds the right people to execute his visions. But it is absolutely remarkable that a payment startup guy kicked off two envelope-pushing companies that have achieved such heights.
Countless rich guys have taken their lucre and tried to change the world, usually to extraordinary failure. Tesla and SpaceX have both changed the world and entire industries (as did PayPal), and they're just getting started.
I don't see anything unhealthy about it. The mindset sees people as people. Nobody is especially special and everyone is simply Themself. Ever seeing others as More Impressive somehow is what is toxic.
You seem to imply that I am insecure about my lack of success or skill in relation to others? And that I wish to bring others down to defend against this insecurity?
Fundamental misunderstanding - we speak different languages and hold different values. I never compare myself to others and am very happy with my life and the way I'm going about it.
And if someone regarded me in this way, I would reject it and tell them to cut it out.
Yeah, the guy is an absolute maniac and based on what I’ve heard I would not want to work at either of those companies, but you can’t argue with his success. He’s broken into two mature markets that have been dominated by massive incumbents for half a century or more. How many business leaders can say the same?
"How could Elon grasp two extremely different and difficult technologies and build such amazing companies within a decade."
Because they're both very well established technologies and there are tons of people with deep expertise in this area.
Space is full of kafkaesque levels of bureaucracy, it's shocking that we haven't been doing this for a long time.
It's the scale of these industries that he's taking on that is mind-boggling, not really the tech itself. It's operational exceptionalism more than anything.
I think it would be odd if there did not exist a person or two at the extreme fringes of the gaussian distribution of one's achievements. The real question is are there more incredible people even further out on the distribution tail that somehow are not so visible to the public.
The guys said at the beginning that they are expecting Falcon to blow up because aerodynamics change significantly once the nose separates.
Stupid question, couldn't they just give Falcon it's own nose so that it doesn't blow up after dragon separates? Dragon could have been mounted on that nose.
I would imagine the escape system is only used when there is something very wrong with the flight. In that case there is usually no hope of recovering the rocket anyway (if it didn't explode, could it make it to the landing site?). The added weight and complexity probably make this a bad trade-off.
I remember seeing someone tackle that question on /r/spacex; the consensus was that, while a first stage booster can return on its own, if it has a full second stage attached the extra mass is too much for the legs (it normally lands nearly empty) and the extra length causes aerodynamics issues (the gridfins should be at the top of the rocket but in that scenario there's quite a bit of rocket above them).
In the event an in-flight abort becomes necessary, odds are that the craft is probably going to be lost no matter what. Adding additional complexity or weight for a vanishingly unlikely scenario likely isn't worth it to them.
> Stupid question, couldn't they just give Falcon it's own nose so that it doesn't blow up after dragon separates? Dragon could have been mounted on that nose.
There are no stupid questions.
The abort system is only there as a last resort in case of booster failure. So in a situation where the abort system is fired, the falcon has probably already failed beyond the point where it is expected to be able to land.
There is a great thread on r/spacex discussing the logistics around trying to save the booster. In the end it was generally agreed not to be possible.
A VERY brief summary of reasons from memory: deceleration causes fuel to rise up in the tanks likely rupturing them from hydralic impact alone, lack of thrust even momentarily causes the rocket to become unstable end to end, only 3 engines are equipped to be relightable and may not relight because the fuel would be at the top of the tanks, too much fuel mass to burn off before landing, too much mass with second stage, etc.
Elon tweeted out the same, that they played with it and deemed it not possible. As such I beleive the rocket was stripped of landing legs and grid fins too. Was a one way ride only.
I’m guessing since this test was not focused on the rocket itself that they just decided it wasn’t a problem worth trying to solve simultaneously with the dragon
It's a problem that does not need to be solved. If all goes well, this was the very last time the launch abort system is ever fired. It's an emergency escape system for when things have already gone pear-shaped, and in most cases would only be triggered after the rocket below it has failed in some way.
Exactly = even if this isn't the last time the launch escape system is used, it'll almost certainly be the last time it's used to escape from a perfectly good booster.
I think one of the purposes of the test was to ensure that the crew can escape safely from a dramatic fireball. It's hard to simulate throwing shrapnel and fuel at the Dragon capsule without actually blowing up the booster.
However, the Falcon wasn't intentionally detonated! This was also by design; if explosive charges were placed down the side and made it come apart naturally, it would come apart in a predictable way. If you know anything about test-driven development, someone would try to made assumptions about the explosion. By allowing an uncontrolled explosion at the time when the Falcon is experiencing the most extreme aerodynamic forces, it's basically creating a worst-case scenario.
SpaceX successfully proved that the Dragon capsule can escape from that worst-case, and that's great news. It'll be flying with crew very soon, I think.
Photos are coming in on Twitter. Thanks to all photographers for the amazing pictures! If you're a photographer and don't want your photos to be linked to from here, please say so.
Official (SpaceX) close-up video of the separation event / IFA:
What about them look unreal? Is it the relative darkness of the actual fire? The photos are processed to some degree - the cameras look to be setup for ultrafast (which makes sense, its trying to capture an explosion), so you can see a lot of "low light" noise and artifacts.
Remember that if you're like me, 99%+ of fireballs that I've ever witnessed were also made up / post processed for maximum impact. Reality could just be more mundane.
it's hard for me to articulate why they look fake, bu i think maybe they look like the photos are really faded and then had colour painted back onto them. something just seems weird.
but as you say, most fireballs i see are post-processed to hell, that's why i'm curious what's up with these - are they more or less post-processed than normal?
Keep in mind that this is taken with zoom lenses and that you're seeing a lot of atmosphere between the camera and the camera. This reduces contrast a lot and in an attempt to make out more detail in editing it can end up looking a little more cartoony (as the dynamic range is compressed so you can see it on a computer screen).
Note the official SpaceX video I just added to the list and how gases are vented from the bottom of the second stage shortly after the abort. May that have been overpressure in the tank(s) caused by the hot exhaust of the SuperDracos in proximity of the tanks? So many questions...
Late update with slow-motion footage from the booster explosion by Doug Jensen. Look at the timer at the top left, it happens between 01:00:25:16 and :17, this is about 25 seconds into the video.
You can manually set the playback rate to values not available from the video player's menu by using the following snippet in the developer console (it works at least with Firefox, if you are not familiar with this: press F12 and go to the Console tab, there is an input box (">>") where you can paste it). This here sets it to 5% of normal playback speed (1.0 is normal speed):
Being able to watch regular (SpaceX) rocket launches live - including deployment of satellites in orbit and landing of boosters - free, for entertainment purposes, is in my opinion one of the most amazing things going at present. As a demonstration of how far technology has progressed to make this all possible it blows my mind.
>> - free, for entertainment purposes, is in my opinion one of the most amazing things going at present.
Except that it isn't. All that classic NASA space footage was shared because it was copyright-free. As products of the US federal government they were not subject to copyright protection. They were transmitted and used everywhere. When "The Six Million Dollar Man" or "Buck Rogers" wanted to use NASA launch footage (or USAF crash footage) they just did. No questions asked.
SpaceX footage isn't from the US fed. It is private and therefore protected copyright. It cannot be used anywhere anytime. We all must ask SpaceX for permission. Use it in a manner that SpaceX disagrees with and you can expect lawyers. You wont see the failure footage from SpaceX ever used as nasa footage was used by countless scifi productions.
So no, this is no amazing thing. While modern footage is a visual feast, in terms of freedom it is a step down from what we once had. I think those running TV news networks (or youtube, or any other distribution network) would rather return to the old system whereby they could use footage however they liked. We won't ever see SpaceX crash footage used for much of anything.
> But SpaceX footage isn't from the US fed. It is subject to copyright. It cannot be used anywhere anytime. We all must ask SpaceX for permission. Use it in a manner that SpaceX disagrees with and you can expect lawyers.
So much pessimism. I think it's great a private for profit corporation is doing as much as it is given it has no obligation to do so.
That's the big change, the lack of obligation. If SpaceX is going to be fulfilling government contracts, on government facilities/ranges, using countless government employees, resulting footage should be free.
It hasn't happened yet, but with human spaceflight nearing we may see SpaceX drafting license deals in a manner NASA never contemplated.
Yup. The last thing SpaceX wants is to see somebody else make a buck from their footage. We have seen NASA logos in a thousand scifi productions. We will never see the SpaceX logo used in such a manner.
SpaceX's trademarked name and logo are still limited by the usual trademark stuff even if they're in public domain video or images.
NASA's copyright policy is US government wide, it's just that most of the rest of the government actively dodges it by hiring photographers and letting them own the copyrights.
I meant that the US government policy is the exception compared to US law, not to the rest of the government. Private companies should not be required to make anything public just because their customer is NASA (or the US government, for that matter.)
Bias? Im critical of the US government's intellectual property policy in relation to spacex contracts and speak to nothing else. If that constitutes some sort of bias then unbiased criticism is impossible.
Id be critical of any privatization of something that was once public domain, specifically spacelaunch footage.
> Id be critical of any privatization of something that was once public domain, specifically spacelaunch footage.
SpaceX footage was never public domain. It’s completely different camera systems, etc. There is no regression here in rights because they are completely different things.
It sounds like your problem is with the government not putting speculations in the launch contracts to demand footage be released to public domain. That’s the real issue and that’s where it should be fixed.
Huh. Is there a record of which photos were originally CC0? If you've already downloaded them as CC0, and they were once licensed as such, you can't just take it back. It's like releasing into the wile with GPLv3. You can re-license it if all the authors agree, but the original code at the point of re-license, if you have a copy, can never lose its GPLv3 status.
Why? NASA partners with SpaceX and other space companies on specific projects. For example, NASA needed a special crew module and so they commissioned SpaceX to design and build the crew dragon.
I don't see why having NASA as a customer means SpaceX loses the right to private property.
If a government agency decided to become a paying customer of your SaaS project, should you be forced to open source all your code because you are now receiving public money? I suspect the answer is the same as with the SpaceX footage - the public may benefit if it was released, but it seems an unreasonable burden.
SpaceX is not 100% NASA funded. NASA contracts SpaceX for a specific product and nasa receives that product. In other words, you do get what you pay for.
Do you believe that any software the government buys must be open sourced? Your tax dollars buy plenty of iPhones and Macs. Should apple release all their software and hardware to you?
I think you are reading too much into my original statement. I did NOT say I think 100% of all SpaceX footage should be made public domain. I specifically stated that if it is funded by govt funding, then it should.
But it’s completely arbitrary. Why the footage and not the source code for all of their software as well?
The footage isn’t what’s being paid for by the government. The only thing that’s being stipulated is that the satellite makes it into its required orbit. Everything else is ancillary to that. This includes footage, software modifications required, internal communications during launch, the parts purchased for the launch vehicle, and on and on. You’re just arbitrarily requiring one of those things should now be public without a justification.
Honestly, I completely skipped your second paragraph. I definitely see a difference in your example. To me, the SpaceX missions done on behalf of the public via NASA/ESA/etc is the result/output of the govt spending. That should always be made public.
The use of the software is just a tool used to produce said output, so no, I would not automatically suggest the the code should be made available. If the govt funding paid for that software, then yes, it should be made available. There's a difference between funding the development of software vs buying a license to use software.
There is a huge difference between software created for the government and software the government uses.
I agree 100% that when the government creates a contract for new software to be written, the government (the public) owns that code and it should be open source.
But if the government uses existing products and services, such as macOS, I think it is wrong to say that the public now owns macOS and that apple must open source their code.
Similarly, is NASA contracts spaceX to design and test a new rocket, then that new rocket arguably belongs to the public and should be open source. But it is wrong to claim that the public now owns everything SpaceX might produce, such as video content, just because SpaceX took on a government agency as a customer.
SpaceX deliveries what they are contracted as a private company to provide. To my knowledge, this does not include putting mission footage into the public domain. Adding additional requirements increases the cost passed on to the tax payer.
Working with vs funded by is the line in my opinion. Did you get private funding to carry out the mission and paid NASA/SpaceX to get a ride and use ISS equipment? Or did you get a grant to fund the mission from govt tax dollars? Private funding = keeping results private
Public funding = making results public
If providing that footage is part of the government contract and paid for by the government then sure, I think that's clearly fair.
However if the government didn't ask for it and hasn't paid for it specifically, if the company chooses to do it anyway then they own it and it's up to them. Otherwise where do you draw the line as to what video and photography created internally by government contractors in their usual course of business should have to be publicly released?
I think they're finding some good PR and passive positive lobbying (where fans write their congressperson about all the cool stuff we can do in space) is coming from their publicity. They're also putting pressure on their competitors (Boeing, Northrop Grumman, etc) by constantly being in the news.
Where is ULA's reusable rocket stage? Where is Arianespace's Starship competitor? Why is NASA building a disposable rocket?
It's important for the future of our sci-fi movies. They ought to be using SpaceX-branded stock footage instead of what, rendering space scenes like a bunch of cavemen?
The quote says right there "for entertainment purposes". Stock footage is not that. And come on, being able to use NASA footage in your own works is one of the least exciting parts about space travel.
>Use it in a manner that SpaceX disagrees with and you can expect lawyers. You wont see the failure footage from SpaceX ever used as nasa footage was used by countless scifi productions.
SpaceX literally uploaded a video of all their crashes spliced together in a comedic montage. It's called How Not to Land an Orbital Rocket Booster.
The crash compilation is public [1] because they were tests with minimal customer risks involved. You wouldn't find footage of CRS-7, with its dozens of NASA payloads, disintegrating on any of SpaceX's official media channels.
[1] But not public domain. It's still copyrighted.
Everything major ever attributed to the USA for all eternity. And otherwise it's not amazing. Seems pretty obvious what they are about.
Or maybe there are several people with very specific interests about what logos appear in the stock footage used in hypothetical documentary style near future science fiction movies ...
Except technology achieved many other things besides shooting rockets into space, one of which is really good CGI, so it's really not about the ability to tell a good visual story.
The fact the content is copyright makes it no less amazing to witness (at least for me and many friends). It has been a source of inspiration in a time of predominantly divisive news.
The quality of the coverage has set a new bar for space companies / agencies. That alone is amazing because we all get to benefit.
I've seen plenty of SpaceX crash footage used by others than SpaceX. While you might have a point when it comes to Intellectual Property, I think you're taking that a bit out of proportion.
> As products of the US federal government they were not subject to copyright protection.
This really is not a good assumption. The federal government has plenty of ways around this. The federal government can buy copyrights, and also enter into work for hire arrangements with contractors and employees. When naked and operating without contracts, the federal government does have this default status, simple boilerplate copy and pasted contracts change this.
I can watch every launch live from my desk in glorious HD with multiple camera views, telemetry, and expert commentary. It costs nothing to watch. This is freaking amazing.
I don't much care for this take. In my opinion, a private and profitable space company is a massive, game-changing advancement in human progress. Maybe, just maybe, we'll actually send people to the planets when it's in somebody's direct financial interest and ability to do so, rather than have to beg a bunch of image-sensitive politicians to fund it.
Against that possibility and chance, I honestly don't give a damn about whether or not some of the footage is public domain. I'd rather argue about who has the right to do what with various bits of launch footage from our Martian colony. Beats the heck out of having more public domain launch footage to use in sci-fi movies, and having our crowning achievement in human space exploration being a handful of short missions to the Moon that left behind absolutely no useful infrastructure, and was only done to show up our geopolitical rivals.
There's a community element to it as well via YouTubers restreaming it. Everyday Astronaut even had tracking cameras set up this time! It does feel like something special is happening. I don't think the wider public are really aware of the implications of all of it yet e.g. reusability, Starlink, Starship, BO, SLS (if that ever gets off the ground). I think it's a really exciting time and I absolutely intend to watch the first full stack Starship/Superheavy launch in person.
Yes, except that SpaceX really is unusually nice about licensing their images and video, compared to other companies. For example, US TV networks don't put their broadcasts about NASA launches into CC0 or CC-A-NC.
And here's Boeing's "Inside the Starliner Pad Abort Test" -- https://youtu.be/L9ifJzokFgA?t=98 -- Copyright @ 2019 Boeing, All rights reserved.
So sure, you can see whatever you like: SpaceX is worse than NASA, or SpaceX is better than almost every other company. Your call.
It dawned on me today that this is in SpaceX's best interest based on their development philosophy.
Think about all the bad publicity that Boeing got when Starliner was off course.
But here SpaceX is constantly blowing things up and everyone is just like "Ah shucks, they will get it next time though."
A lot of that has to do with how out in the open they have made a lot of these failures and tests. Everybody expects it now and views it in a positive light.
Part of that is also based in reality - SpaceX follows a more Soviet-style, hardware-rich approach than Boeing or ULA, where tests (including failed ones) are much more frequent. In terms of PR, this has given them a record of public failures followed by later success, so the public is more primed to give them the benefit of the doubt when something goes wrong. (Even if the thing that goes wrong isn't actually part of a test.)
You say this as if they actually are actually having things go wrong on stream.
This test was exactly as planned. The one failure they did have unintentionally blow up (the dragon fueling explosion) was actually not on a live stream.
All that did kinda work for their attempts at landing the first stage a few years back though, however that was heavily wrapped in “experiment” and Was PR covered at every moment.
They’ve had two falcon 9 systems explode unintentionally. The CRS-7 system failed in flight, and AMOS-6 failed on the launch pad during fueling. They also unintentionally blew up a Crew Dragon capsule.
It is true that they do testing differently from Boeing. Boeing uses a NASA testing plan where hardware is verified on the ground through extensive part or subsystem-level testing. This method has a downside which is that many things end up needing a higher factor of safety than absolutely necessary due to uncertainty in the risk calculations.
SpaceX uses a different testing strategy where a lot more stuff is tested as a complete system. There is increased potential for full system failures, which we have seen, but the entire system can be vetted more quickly.
> SpaceX uses a different testing strategy where a lot more stuff is tested as a complete system.
I'm sure they are tested as integrated systems, but they are also exercised extensively ahead of that. The Super Dracos used for the launch escape system have been test-fired since well before the Crew Dragon got its name.
Just adding that AMOS-6 actually failed ruing fueling failed before a planned hot fire test, not during fueling before a planned launch. Due to that, it was not on an official live stream.
Though I think it was recorded by at least one unofficial one covering the hot fire.
It’s easy to dislike Boeing. They are a bloated and corrupt company that were unfairly awarded $2 billion more than SpaceX for the same project. Despite that advantage they still showed up to the party with a vastly inferior rocket system.
For me personally I can only wonder how much further along SpaceX might be if all the money we’ve given to Boeing had instead gone to SpaceX.
I have a feeling that's also because rather than build a business around making things as expensive as possible and dragging contracts out as long as possible, they're trying to make significant advances in technology. While I know it's not necessarily true, it feels like the US Space Program has been a glorified corporate welfare scheme since Saturn V (prior to SpaceX shaking things up).
Well, yeah, it is. Or to put a very slightly more positive spin on it, they want to subsidize a company with a military program so that it has surplus capacity. A bit like the way we subsidize farmers: we want more production than we need so that if something happens (weather, somebody going out of business, bad harvest, etc) we've still got enough.
Whether we really need that much military capacity... well, I'll leave that up to you. But it's not really hidden that we're throwing more money at them than the market would call for. This corporate welfare scheme is very glorified.
Great result. One thing stood out, in the commentary they sometimes used feet and sometimes meters. Better just to stick to metric to avoid the mess. Reminds me various stories, when mix up between metric and imperial made space missions fail. So SpaceX teams should have stronger focus on avoiding this.
I think you're confusing the public broadcast commentary with the engineering that goes into the actual hardware. There are slightly different levels of rigor involved... (and very different audiences)
I think it should be uniform, until it becomes a habit. Making it lax in one area can backfire in another.
That's besides the point that someone should be advancing the usage of metric for the general public, and who is best suited for it, if not someone already invested in it like SpaceX. Their HUD in the video is already using metric for example.
Bear in mind that the audience of the webcast is not uniformly comfortable with metric units. Using both makes sure that everyone has a sense of the scales involved.
By using them both, it's a good way to give someone who doesn't use metric a basic understanding of the conversions.
That's the point. In order to make the public comfortable, metric should be used for them. That's the only way to gain comfort. Not using it only prolongs the issue.
The government basically gave up on it, leaving metrication in shambles. So SpaceX is in good position to do something about it.
And using one or another intermittently only adds confusion IMHO, unless you literally use both for each value which is even more annoying (at least to me).
It's cool that you're so passionate about this, but bear in mind your intitial comment was suggesting that SpaceX was risking a mission failure by mixing units in a broadcast intended for public consumption.
It's both. Presenting to the public and being consistent. If they are training their own teams to be used to it, it should be consistent everywhere. And public will benefit from it, like above.
Yeah, he comes across as a super unassuming dude in the webcasts, but he has definitely "been there, done that" when it comes to putting stuff in space.
Which is great, so it would be good to translate that to public commentary with metric too :)
Also, surprised to find so many downvotes here. I suppose some still oppose the metrication effort and want to prolong the usage of imperial units, but are too embarrassed to admit it.
Congrats SpaceX team! I hope they post the view from the Crew Dragon vehicle of the Falcon 9 breaking up. That seems to be the one view that was missed (in addition to splashdown from the aircraft angle)
Was there mention of why they did not do a launch escape while the F5 was at full throttle? I understand this reduces the risk and was probably deemed to be good enough of a test, but I was expecting the test to be "worst case scenario" or in other words, F5 on full power at MaxQ.
I think that "F5 on full power at MaxQ" is not a worst case scenario, it's more like "flying nominally" - doing it at maxQ is certainly the thing to do - but "on FS flameout" is more realistic
FS flameout may be more realistic, but you need to test for worst case scenarios. Having F5 throttle down allows any kind of Dragon acceleration to pull it away from the Falcon. The critical design element of an crew ejection system is that it needs to out-accelerate the rocket so testing while the Falcon remained at full power seems logical. They probably have reasons not to do it.
The Falcon 9 never goes through MaxQ at full throttle, throttling down before MaxQ and up after MaxQ is part of the normal flight path. This Falcon 9 followed the normal flight path right up to the point where the abort was artificially induced.
I believe the abort did actually take place at full throttle though, it happened at the point of max drag which occurs shortly after Max Q, and is after the rocket has throttled back up. The intent was definitely to trigger the abort at the worst time during the normal flight path.
This test seems more useful? Why put it through a path that can’t happen? If throttle is out of control and randomly going, that’s a good case to trigger an abort right then.
Because if the throttle is out of control then that's exactly the case you'll be in? One where you're at MaxQ and have throttle at full. The test imo should be done at the worst possible scenario that the rocket could physically be in (i.e., no need to test at a speed/stress that is physically impossible to reach, but what if the rocket starts thrusting unexpectedly in a different direction or something?)
If your throttle is out of control, you presume that would trigger an abort. Instead of waiting until you are at max speed in the wrong part of the flight?
It can happen at maximum speed. Before you say that Falcon is not at full throttle when at maximum speed, sure. Let's assume the worst case scenario, Falcon reaches max q and due to a glitch throttles up to full throttle and starts veering off course. This is a worst case scenario probably, and I was surprised that SpaceX did not test this extreme possibility.
That's our point. Testing with the assumption that Falcon accepts throttle down command from the Dragon seems like a waste of test scenario.
Good point about MaxQ, but it was not an important part of my question.
What I was surprised is that the Dragon sent a command to the Falcon to shut down the engines. In a catastrophic scenario, it may be that the Falcon does not accept commands and is "stuck" at full throttle. I was expecting them to test ejection while the rocket is at full power without shutting down engines.
I guess they do not need to test it that way, they can easily calculate or measure if the acceleration was high enough and by initiating throttle down the capsule minimizes the risk of being hit by rocket debris after it falls apart. In a real life emergency such risks are acceptable, but in a test probably unnecessary.
If the "throttle down" before MaxQ fails? I would assume that Dragon would detect the anomaly and abort immediately, before the extra acceleration had time to increase velocity enough to cause an issue.
Dragon doesn't need Falcon 9 to throttle down to abort, the Falcon 9 needs to slow down a bit during MaxQ, but the instantaneous acceleration of the Falcon 9 during abort isn't supposed to matter.
344 comments
[ 2.5 ms ] story [ 276 ms ] threadLooks like the test went well.
Edit: Splashdown
Keep in mind it wouldn't be able to choose its landing site either.
This abort happened after the rocket reached max Q (highest dynamic pressure) when it was flying East (and still upward, but to get to orbit you must fly sideways over water). Returning West to get back over land would be fuel prohibitive on a fully loaded crew capsule.
The reusable falcon 9 stages have almost nothing in them when they fly back to land.
See trajectories: https://i.redd.it/xaisqxao5ef01.png
“The reason we decided not to pursue (powered landings) heavily is it would have taken a tremendous amount of effort to qualify that for safety, particularly for crew transport,” Musk said. “And then there was a time when I thought that the Dragon approach to landing on Mars, where you’ve got a base heat shield and side-mounted thrusters, would be the right way to land on Mars, but now I’m pretty confident that is not the right way, and that there’s a far better approach.” [0]
[0] https://spaceflightnow.com/2017/07/19/propulsive-landings-ni...
The design has 4 parachutes, likely for packaging and design constraints, but also provide some level of redundancy.
My comment wasn't clear now that I re-read it, but if you use a propulsive landing after a propulsive abort, you'd need additional fuel. If you remove the parachutes, that weight could then be used for landing fuel, but fuel weight may still exceed that. I haven't run the numbers.
The aborted dragon, after leaving Falcon, is now a self-contained vehicle carrying multiple people. It is a redundant and failsafe safety part of the entire system, but it's hard for me to believe it would be designed with everything having to work perfectly after an abort in order to safely return the occupants. Guidance and Control, life support, propulsion...
I'm mainly wondering if you were aware of the systems they would have in place on a propulsive return.
It seems that the amount of fuel to return all the way downrange back to land on a propulsive abort would be more than the parachute weight, which forces a water landing. And since you already design the capsule for carrying those parachutes, you might as well use them on a normal landing as well. That cuts down on additional weight for an abort return. I also don't know that if you have a successful launch, that you have enough reserve from un-used launch abort fuel to then land the capsule without chutes. Seems unlikely, especially with needing failsafe/redundancy.
One additional issue with propulsive lsnding is that you need legs, and they need to penetrate the heat shield. This significantly complicates and weakens an absolutely critical part.
Not sure that's true. The chutes bring the speed of the capsule down quite a bit, just a short burst of the dracos at the last few feet could allow it to softly land and wouldn't require much propellant. This is exactly what the Soyuz does. My guess is that this approach was rejected by NASA (not SpaceX) due to complexity rather than feasibility.
If the engines don't start, or you don't get the predicted thrust out of them, well, that's why it's called a suicide burn.
Fair enough, but this is exactly what the Soyuz has done for decades, and NASA (as well as Roscosmos) found the approach to be acceptable for human spaceflight. It may introduce complications, but it's clear that it's doable.
The boats get there pretty quickly.
The time required is for safety checks and so on - there's some pretty nasty materials involved in those thruster engines, and all that stuff has to be checked first.
Dragon2 is no use in the efforts to build a city on Mars. And even for a Moon colony, its too small. Its just there to earn money from flying people to the ISS and back. And for that its already good enough.
Also there, it still takes a while for boats to arrive.
I can't see Starship being approved for Nasa use by 2024 even if it were flying today.
They're working on a second stage that can carry a few more astronauts and land itself, it's a bit bigger though ;)
https://www.spacex.com/starship
From my understanding, the host meant that getting the dragon and crew back to the shore would take 2 hours, not the recovery boat to get to them. They could probably even have helicopters around the area which could fly and pick the dragon up.
Can't wait for the crewed launch. Historic moment for the United States space program.
Also the flight can be delayed if NASA decides to extend astronauts' time on ISS which would require additional training for them.
That was all expected to happen and why they launch these things out over the ocean. These rockets also usually have a self-destruct mechanism that a range safety officer can trigger if the rocket starts coming back towards land.
My guess is it was armed for the early stages of the flight (when there was still a risk something could go seriously wrong and the rocket could start heading towards Orlandit), but it was disarmed (or just given very generous parameters) once the rocket was downrange a ways.
(and on an entirely unrelated note, I really hate watching those parachutes bounce off each other. I know it must be perfectly safe or else it wouldn't have been the unquestioned method off choice for at least half a century, but it looks so uncontrolled it gives me nausea)
I'm not sure whether this would actually make a difference, but if you know it works at nominal fuel weight then you have some confidence it would work during a real launch.
It looked too instantaneous and clean of an explosion to have broken up naturally.
I suspect the FTS was appropriately triggered and that the 2nd stage simply survived the initial carnage via happenstance or potentially unintentionally due to changes in the structure regarding the missing front piece.
It was a very different "failure", which would naturally look different.
https://raumzeit-podcast.de/2020/01/17/rz083-spacex/
https://old.reddit.com/r/spacex/comments/epzayc/german_raumz...
EDIT: https://spaceflightnow.com/2020/01/16/spacex-abort-test-serv... has more details about the recovery operations and the Air Force's role.
They expected the splashdown to happen several seconds later than it did. This could mean the capsule was going faster than it should have before its parachute deploy or it didn't slow down enough when hitting the water which would be worse.
Finally the main parachutes where touching each other pretty aggressively it wouldn't seem than unfathomable that two or more of them get tangled up, I don't think there is a backup solution for if that happens.
Regarding splashdown timing, we will see. They've been testing this extensively in the background, and parachutes have been a pain point all around.
You did so again here.
In both instances it is unclear what you're trying to convey.
Coupled with taking a neutral comment personally, the simplest conclusion to make is that you're not writing for the benefit of anyone else, besides yourself.
Language's primary function is to communicate information. Our minds are like compilers that translate human-readable language into simplified neural impulses. If you write code with poor syntax, the human mind will still compile it, but you're going to get a lot of unexpected behavior, i.e "what the fuck is this guy trying to convey?"
As far as I understand it once the capsule ejected the Falcon 9 was destinated to break up (due to aerodynamic forces) and that break up would trigger the FTS automatically. So the AFTS triggering was part of the plan.
That said it also doesn't really matter - the test was about what happens to the capsule when something goes wrong and not what happens to the booster.
I also have no idea what an unplanned or unexpected controlled detonation looks like. It seems like a controlled explosion has to be planned or expected by definition?
Like others have pointed out: as far as F9 was concerned, the test ended when Dragon detached. Whatever happened after that point is immaterial to the test, so to start saying that would require a reflight is nonsense.
> so to start saying that would require a reflight is nonsense
I said "most likely" and "if you want to be safe enough" I'm not sure why you assumed I meant "require"
I think your reception here would be better if you dropped the attitude and recognized that your comment used pure speculation to imply that the outcome of the test was negative. Maybe that was not your intent, but then you should have asked more open-ended questions rather than slant them so obviously negatively.
What evidence do you have that it was a "controlled detonation"? Seems like you're making baseless assumptions and then getting upset when people don't understand what you're trying to say.
A rocket with no nosecone will basically lose structural integrity very, very quickly. A rocket 'breaking down' doesn't look like fluttering bits and bobs raining down, it looks like a big fireball.
https://www.reddit.com/r/spacex/comments/eq24ap/rspacex_infl...
Nothing I've seen or heard yet suggests that the test experience was outside expectations.
As far as I know the AFTS consists of a detonating cord that runs along the tanks for fuel and oxidizer and rips them open when triggered. The substances mix and deflagrate and only the massive parts will actually reach ground (or sea).
While you can control for variables greatly when you're flying under an engine, I'd imagine it's not so easy to control for environmental variables (such as local variations in wind speed) when you're landing under parachutes. It probably would have been safer for the broadcasters to have had an estimated time of landing with a +/- 20 or so seconds on the display, but I personally doubt landing a little sooner than expected will be a major concern.
I think it's incredibly satisfying to note that SpaceX is so good at the launch sequence with the Falcon 9 that there were zero delays except weather. With any new rocket system test, I completely expect there to be multiple delays with the countdown.
Again, congrats to everyone and their hard work.
Also, I'm really interested in knowing if the fireball was performed by the automated abort system.
I would love these to be the answer, so looking forward to clarification.
As for the fireball, from the press conference I got the sense that the fireball was not triggered manually, that the rocket just broke up.
Again, on neither I'm 100% sure.
No, that was the rocket breaking up and exploding. If the range safety system had triggered, it would have blown up the second stage, which flew off and crashed into the ocean in a massive explosion
The capsule controlled the abort. It shuts down the main engines then lights it own engines. These things aren't instant, it takes a second to spin up turbo pumps and get fuel flowing and for the fuel in the lines of the main engine to flow out after it sends the signal - that's why the rocket exhaust was still burning as the abort system lit up.
It might not necessarily be an issue. The steps took only split-seconds anyways from what it sounds. Shutting down the main engines helps to escape but appears to not be required for a successful abort. The order might be required though (e.g. the commands need to be sent before the connection between the vehicles is severed) or just beneficial (maybe to give the turbo-pumps of the main engiens a few more moments to spin down already).
One thing that is clear is that the phrase of launching American astronauts on American rockets from American soil will be used. Multiple times. That's as sure as SpaceX livestream hosts using the formulation 'Historic' Launch Complex 39A ;)
Elon says, Hardware for first launch will be ready end of Feb, but lots of double checks have to happen before launch and schedules lined up for ISS. Expect launch to happen in 2Q.
Elon adds that they need to get the space craftback and check it over to make sure all is well and there is nothing to address.
Elon teases trying to catch the dragon on re-entry to remove some of the constraints a splash down imposes.
Worth remembering the Crew Dragon wouldn't need a major redesign to do a powered landing. That's one of the reasons why the escape system uses liquid fuel - it needs to be throttlable - instead of a simpler solid fuel design.
39B is going be used by NASA's Space Launch System. Boeing finally shipped a booster last week.
https://www.youtube.com/watch?v=sDnABgxUeV4
Challenger did not. Later shuttle launches included the "Inflight Crew Escape System", or ICES.
https://spaceflight.nasa.gov/shuttle/reference/shutref/escap...
The only shuttle to ever was anything resembling a launch abort system were the first few flights of Columbia. It had ejection seats for the pilot and commander. However, later statements by NASA and the astronauts said that using them probably would’ve resulted in the death of the astronauts due to descending through the extremely hot exhaust of the launch.
The key events of the disaster took place over about three seconds.
A leak of high-temperature gas in the right solid rocket booster damaged the external stack of solid rocket boosters and external fuel tank.
The damage to the external tank caused it to come apart, and resulted in a fireball from the released liquid oxygen and hydrogen. The solid rocket boosters broke free of their mountings as the disaster unfolded.
The Challenger orbiter momentarily survived both the fireball and external tank failure. But those events made it impossible to keep the orbiter correctly oriented.
The loss of proper orientation while travelling ~1000mph meant Challenger was hit with very high stress forces, far beyond anything it was designed to survive, and swiftly broke apart.
Shortly afterward, the Range Safety Officer remotely detonated both solid rocket boosters, which had survived the disaster mostly intact and were careening out of control.
More detail at Wikipedia: https://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disas...
I suppose it is worth mentioning that it did not "explode" in the sense people normally understand though: a blast of rapid combustion of fuel.
Technically it was a deflagration, not a detonation, but energetic deflagrations are a type of explosion.
Slightly hard to find digitally but it's the first "episode" here: https://smile.amazon.com/The-Challenger-Disaster/dp/B00GQUM7...
William Hurt does a great job in it and its pretty interesting!
(Be careful because there's also a worse seeming/rated movie with the same name that came out recently.)
We shouldn’t discount luck, but you can respect the traits above without the derogatory terms (“fan boi”).
As the root post says, it is amazing what Musk has achieved, and I'd love to learn what the secret is. I suspect it's that he knows the limits of his own capabilities so he finds the right people to execute his visions. But it is absolutely remarkable that a payment startup guy kicked off two envelope-pushing companies that have achieved such heights.
Countless rich guys have taken their lucre and tried to change the world, usually to extraordinary failure. Tesla and SpaceX have both changed the world and entire industries (as did PayPal), and they're just getting started.
You seem to imply that I am insecure about my lack of success or skill in relation to others? And that I wish to bring others down to defend against this insecurity?
Fundamental misunderstanding - we speak different languages and hold different values. I never compare myself to others and am very happy with my life and the way I'm going about it.
And if someone regarded me in this way, I would reject it and tell them to cut it out.
Because they're both very well established technologies and there are tons of people with deep expertise in this area.
Space is full of kafkaesque levels of bureaucracy, it's shocking that we haven't been doing this for a long time.
It's the scale of these industries that he's taking on that is mind-boggling, not really the tech itself. It's operational exceptionalism more than anything.
I really wish more billionaires, govts and VCs poured money into serious hardware and manufacturing.
It really seems like US has lost its edge in manufacturing. 90% of the things in the mall/online seem to be from China.
The economy may be doing great today but really not a great sign of the future.
The guys said at the beginning that they are expecting Falcon to blow up because aerodynamics change significantly once the nose separates.
Stupid question, couldn't they just give Falcon it's own nose so that it doesn't blow up after dragon separates? Dragon could have been mounted on that nose.
There are no stupid questions.
The abort system is only there as a last resort in case of booster failure. So in a situation where the abort system is fired, the falcon has probably already failed beyond the point where it is expected to be able to land.
A VERY brief summary of reasons from memory: deceleration causes fuel to rise up in the tanks likely rupturing them from hydralic impact alone, lack of thrust even momentarily causes the rocket to become unstable end to end, only 3 engines are equipped to be relightable and may not relight because the fuel would be at the top of the tanks, too much fuel mass to burn off before landing, too much mass with second stage, etc.
Elon tweeted out the same, that they played with it and deemed it not possible. As such I beleive the rocket was stripped of landing legs and grid fins too. Was a one way ride only.
However, the Falcon wasn't intentionally detonated! This was also by design; if explosive charges were placed down the side and made it come apart naturally, it would come apart in a predictable way. If you know anything about test-driven development, someone would try to made assumptions about the explosion. By allowing an uncontrolled explosion at the time when the Falcon is experiencing the most extreme aerodynamic forces, it's basically creating a worst-case scenario.
SpaceX successfully proved that the Dragon capsule can escape from that worst-case, and that's great news. It'll be flying with crew very soon, I think.
Official (SpaceX) close-up video of the separation event / IFA:
https://twitter.com/SpaceX/status/1218976479150858241
Great shots of the fireball:
https://twitter.com/GregScott_photo/status/12189514406910730...
https://twitter.com/BrandonHSlam/status/1218923590260645889
https://twitter.com/Mimikry_/status/1218937739590230016
https://twitter.com/_flsportsguy/status/1218930068887613441
https://twitter.com/thelanjampod/status/1218949597231489024 (multiple frames)
Falling booster or second stage (the ratio of black to white hull area is the same on both stages, so I can not tell which one of both it is):
https://twitter.com/mike_deep/status/1218926880381902849/pho...
Impact of said part on the surface of the sea:
https://twitter.com/johnpisaniphoto/status/12189461666389401...
Infrared images:
https://twitter.com/turndownformars/status/12189257207366000...
https://twitter.com/turndownformars/status/12189415996080783...
In-flight abort test appearing on the weather radar:
https://twitter.com/NWSSpaceflight/status/121892435399747584...
https://twitter.com/wxmeddler/status/1218925147861790720 (animation)
Lift-off and others:
https://twitter.com/TrevorMahlmann/status/121896406755938713...
https://twitter.com/RDAnglePhoto/status/1218968896885215235 (viewing angle and height suggests it was taken from the roof of the VAB (vertical assembly building))
Splash-down of the capsule:
https://twitter.com/FutureJurvetson/status/12189766841347153... (strange that Mr. Innsprucker called the parachutes white-orange. That looks rather like red?)
Remember that if you're like me, 99%+ of fireballs that I've ever witnessed were also made up / post processed for maximum impact. Reality could just be more mundane.
but as you say, most fireballs i see are post-processed to hell, that's why i'm curious what's up with these - are they more or less post-processed than normal?
https://youtu.be/mhrkdHshb3E?t=1168
https://www.youtube.com/watch?v=vqW0LEcTAYg
https://twitter.com/spacex/status/1218976479150858241?s=21
https://www.youtube.com/watch?v=06svtpboEJs
You can manually set the playback rate to values not available from the video player's menu by using the following snippet in the developer console (it works at least with Firefox, if you are not familiar with this: press F12 and go to the Console tab, there is an input box (">>") where you can paste it). This here sets it to 5% of normal playback speed (1.0 is normal speed):
Except that it isn't. All that classic NASA space footage was shared because it was copyright-free. As products of the US federal government they were not subject to copyright protection. They were transmitted and used everywhere. When "The Six Million Dollar Man" or "Buck Rogers" wanted to use NASA launch footage (or USAF crash footage) they just did. No questions asked.
SpaceX footage isn't from the US fed. It is private and therefore protected copyright. It cannot be used anywhere anytime. We all must ask SpaceX for permission. Use it in a manner that SpaceX disagrees with and you can expect lawyers. You wont see the failure footage from SpaceX ever used as nasa footage was used by countless scifi productions.
So no, this is no amazing thing. While modern footage is a visual feast, in terms of freedom it is a step down from what we once had. I think those running TV news networks (or youtube, or any other distribution network) would rather return to the old system whereby they could use footage however they liked. We won't ever see SpaceX crash footage used for much of anything.
What I am talking about. Six Million Dollar Man opening: https://www.youtube.com/watch?v=bGO57y4td-c
Original NASA footage: (Crash at about 2:00) https://www.youtube.com/watch?v=50dDWT48b9M
So much pessimism. I think it's great a private for profit corporation is doing as much as it is given it has no obligation to do so.
That's the big change, the lack of obligation. If SpaceX is going to be fulfilling government contracts, on government facilities/ranges, using countless government employees, resulting footage should be free.
It hasn't happened yet, but with human spaceflight nearing we may see SpaceX drafting license deals in a manner NASA never contemplated.
NASA's copyright policy is the exception, not the rule.
NASA's copyright policy is US government wide, it's just that most of the rest of the government actively dodges it by hiring photographers and letting them own the copyrights.
Id be critical of any privatization of something that was once public domain, specifically spacelaunch footage.
SpaceX footage was never public domain. It’s completely different camera systems, etc. There is no regression here in rights because they are completely different things.
It sounds like your problem is with the government not putting speculations in the launch contracts to demand footage be released to public domain. That’s the real issue and that’s where it should be fixed.
I don't see why having NASA as a customer means SpaceX loses the right to private property.
If a government agency decided to become a paying customer of your SaaS project, should you be forced to open source all your code because you are now receiving public money? I suspect the answer is the same as with the SpaceX footage - the public may benefit if it was released, but it seems an unreasonable burden.
Do you believe that any software the government buys must be open sourced? Your tax dollars buy plenty of iPhones and Macs. Should apple release all their software and hardware to you?
The footage isn’t what’s being paid for by the government. The only thing that’s being stipulated is that the satellite makes it into its required orbit. Everything else is ancillary to that. This includes footage, software modifications required, internal communications during launch, the parts purchased for the launch vehicle, and on and on. You’re just arbitrarily requiring one of those things should now be public without a justification.
The use of the software is just a tool used to produce said output, so no, I would not automatically suggest the the code should be made available. If the govt funding paid for that software, then yes, it should be made available. There's a difference between funding the development of software vs buying a license to use software.
Yes. Public money, public code. https://publiccode.eu/
I agree 100% that when the government creates a contract for new software to be written, the government (the public) owns that code and it should be open source.
But if the government uses existing products and services, such as macOS, I think it is wrong to say that the public now owns macOS and that apple must open source their code.
Similarly, is NASA contracts spaceX to design and test a new rocket, then that new rocket arguably belongs to the public and should be open source. But it is wrong to claim that the public now owns everything SpaceX might produce, such as video content, just because SpaceX took on a government agency as a customer.
However if the government didn't ask for it and hasn't paid for it specifically, if the company chooses to do it anyway then they own it and it's up to them. Otherwise where do you draw the line as to what video and photography created internally by government contractors in their usual course of business should have to be publicly released?
Where is ULA's reusable rocket stage? Where is Arianespace's Starship competitor? Why is NASA building a disposable rocket?
I don't think the opinion of "those running TV news networks" really matters all that much when we're talking about space.
SpaceX literally uploaded a video of all their crashes spliced together in a comedic montage. It's called How Not to Land an Orbital Rocket Booster.
https://youtu.be/bvim4rsNHkQ
Even crash footage is good PR for them. There are still millions of Americans who do not know what SpaceX is or what it does.
[1] But not public domain. It's still copyrighted.
We will if SpaceX allows it. How can you be sure they won't?
This is probably true, but it's hard to be certain that they'd prevail. Has this actually been tested in court?
Putting the legal aspects to one side, do you not think it's amazing? If not, what would it take to impress you?
Or maybe there are several people with very specific interests about what logos appear in the stock footage used in hypothetical documentary style near future science fiction movies ...
Except technology achieved many other things besides shooting rockets into space, one of which is really good CGI, so it's really not about the ability to tell a good visual story.
The quality of the coverage has set a new bar for space companies / agencies. That alone is amazing because we all get to benefit.
This really is not a good assumption. The federal government has plenty of ways around this. The federal government can buy copyrights, and also enter into work for hire arrangements with contractors and employees. When naked and operating without contracts, the federal government does have this default status, simple boilerplate copy and pasted contracts change this.
Except that it is. Free as in beer, not as in freedom.
Against that possibility and chance, I honestly don't give a damn about whether or not some of the footage is public domain. I'd rather argue about who has the right to do what with various bits of launch footage from our Martian colony. Beats the heck out of having more public domain launch footage to use in sci-fi movies, and having our crowning achievement in human space exploration being a handful of short missions to the Moon that left behind absolutely no useful infrastructure, and was only done to show up our geopolitical rivals.
Unless it's critical or satirical of the military, like Starship Troopers.
The Spacex presenters generally have a mix of knowlege and charisma that news presenters don't.
And here's Boeing's "Inside the Starliner Pad Abort Test" -- https://youtu.be/L9ifJzokFgA?t=98 -- Copyright @ 2019 Boeing, All rights reserved.
So sure, you can see whatever you like: SpaceX is worse than NASA, or SpaceX is better than almost every other company. Your call.
Think about all the bad publicity that Boeing got when Starliner was off course.
But here SpaceX is constantly blowing things up and everyone is just like "Ah shucks, they will get it next time though."
A lot of that has to do with how out in the open they have made a lot of these failures and tests. Everybody expects it now and views it in a positive light.
This test was exactly as planned. The one failure they did have unintentionally blow up (the dragon fueling explosion) was actually not on a live stream.
All that did kinda work for their attempts at landing the first stage a few years back though, however that was heavily wrapped in “experiment” and Was PR covered at every moment.
Not all accidents have been on an official live stream but I’ve seen more accidents from Spacex than I’ve seen launches from Boeing and friends.
It is true that they do testing differently from Boeing. Boeing uses a NASA testing plan where hardware is verified on the ground through extensive part or subsystem-level testing. This method has a downside which is that many things end up needing a higher factor of safety than absolutely necessary due to uncertainty in the risk calculations.
SpaceX uses a different testing strategy where a lot more stuff is tested as a complete system. There is increased potential for full system failures, which we have seen, but the entire system can be vetted more quickly.
I'm sure they are tested as integrated systems, but they are also exercised extensively ahead of that. The Super Dracos used for the launch escape system have been test-fired since well before the Crew Dragon got its name.
Though I think it was recorded by at least one unofficial one covering the hot fire.
SpaceX is basically Kerbal Space Program in real life
For me personally I can only wonder how much further along SpaceX might be if all the money we’ve given to Boeing had instead gone to SpaceX.
Whether we really need that much military capacity... well, I'll leave that up to you. But it's not really hidden that we're throwing more money at them than the market would call for. This corporate welfare scheme is very glorified.
That's besides the point that someone should be advancing the usage of metric for the general public, and who is best suited for it, if not someone already invested in it like SpaceX. Their HUD in the video is already using metric for example.
By using them both, it's a good way to give someone who doesn't use metric a basic understanding of the conversions.
The government basically gave up on it, leaving metrication in shambles. So SpaceX is in good position to do something about it.
And using one or another intermittently only adds confusion IMHO, unless you literally use both for each value which is even more annoying (at least to me).
The goalposts seem to have drifted a bit here...
[1]: https://airandspace.si.edu/support/wall-of-honor/col-john-in...
Also, surprised to find so many downvotes here. I suppose some still oppose the metrication effort and want to prolong the usage of imperial units, but are too embarrassed to admit it.
I believe the abort did actually take place at full throttle though, it happened at the point of max drag which occurs shortly after Max Q, and is after the rocket has throttled back up. The intent was definitely to trigger the abort at the worst time during the normal flight path.
Although there's probably not much of a difference if they full throttled shortly after MaxQ and then aborted.
That's our point. Testing with the assumption that Falcon accepts throttle down command from the Dragon seems like a waste of test scenario.
What I was surprised is that the Dragon sent a command to the Falcon to shut down the engines. In a catastrophic scenario, it may be that the Falcon does not accept commands and is "stuck" at full throttle. I was expecting them to test ejection while the rocket is at full power without shutting down engines.
I guess they do not need to test it that way, they can easily calculate or measure if the acceleration was high enough and by initiating throttle down the capsule minimizes the risk of being hit by rocket debris after it falls apart. In a real life emergency such risks are acceptable, but in a test probably unnecessary.
Dragon doesn't need Falcon 9 to throttle down to abort, the Falcon 9 needs to slow down a bit during MaxQ, but the instantaneous acceleration of the Falcon 9 during abort isn't supposed to matter.