I agree with the general sentiment, however SpaceX and others have said that this particular explosion would not have harmed any astronauts. The Dragon 2 crew capsule has a launch abort system - if an explosion happens the Dragon launches off to a safe distance using its own thrust.
Why do they not use this continency for saving the capsule & non-living cargo, as well? Surely the recommissioning costs would be less than full replacement of equipment+cargo & would give working knowledge for any future "live cargo" aborts.
They could, when Dragon 2 is in use for supplying ISS. But Dragons do not carry the kinds of payloads lost in this case. The satellite is on top of the second stage and covered by fairings. There's no craft on top of second stage, so there is no launch escape system.
There is no point of a launch abort system if the cargo saved would not survive being saved. You cannot just accelerate a satellite to 10g then drop it into the ocean by parachute. Humans in flight suits, strapped to chairs inside watertight capsules, are actually pretty tough in comparison.
IIRC the stress on the capsule is actually considerably greater during LPAS than during any normal launch (remember that the capsule has to outrun the rocket if anything goes wrong), not to mention a potentially hard landing.
So overall unlike humans there is actually pretty low chance for the cargo to survive intact and satellites isn't something you can just fix a dent in, taking it apart doing a full analysis of every component checking for stress, microfractures, and pretty everything else under the sun would probably cost just as much if not more than building a new one.
In this case insurance is pretty much the way to go, especially once you consider the added costs of actually building a LPAS or IFAS for satellites / in orbit release payloads and the fact that they have very little chance of surviving the abort without any damage.
Well, SpaceX does have a launch escape system, as did past US rockets and the current Soviet/Russian one (https://en.wikipedia.org/wiki/Launch_escape_system), it's the Shuttle that was anomalous in having no provisions for crew survival if something happened after the first few test flights.
Although look at the bottom of that link, operationally they've been a mixed blessing, saving one Soyuz crew, but another one wasn't safed after a scrubbed launch and killed a bunch of pad workers.
This stuff is hard, "rocket science" really does deserve its connotations of difficulty, and is inherently dangerous.
Planned, but the bailout method in particular was deemed pretty likely to wind up with a bunch of dead astronauts, as it required unbuckling and making your way to a hatch and jumping out at potentially several times the speed of sound from an out-of-control launch vehicle.
Not to mention emergency life support requiring active intervention to work. It was like having seat belts that required you to push a button to engage in the event of a crash.
Not surprisingly not a single astronaut survived Columbia's depressurization at altitude, because of failure to engage active life support. (A blessing because they had a literal snowballs chance in hell of surviving what followed, but still...)
Launch aborts are not an options for any tumbling vehicle. A launch abort from a spinning/tumbling rocket would see the capsule fired strait into the ground. Any out of control vehicle is pretty much a lost cause.
Shuttle's abort modes, including the bailouts, were premised on the craft being under control. Given the forces involves, if it wasn't under control it probably was about to disintegrate. But the same is true of spaceX-style capsule launches. Whether parachutes would correct a tumbling capsule, or rip it in half, is an open question. They both need to initiate abort procedures at least a millisecond before the craft departs into uncontrolled flight.
(And aborts can be triggered automatically, or by someone on the ground.)
Launch abort though can be fired well in advance of a rocket tumbling though. There's a pretty narrow recoverable angle throughout the launch, the rocket is lost well before the crew can't be saved.
Spinning's entirely possible to survive. The Saturn missions tested it (and it was a really good test - something went wrong and the rocket actually went out of control) - https://www.youtube.com/watch?v=AqeJzItldSQ
A tumble should be fairly trivial to detect and fire only when the capsule's in its upwards pointing portion of the tumble. Plus, you'd only be firing into the ground if you're pretty early in the launch - the Dragon launch abort only sent it up a kilometer or so. Finally, the launch abort is pretty sensitive - deviating not far off the right direction should trigger it, before a full-on tumble.
Those alone made it a serious death trap, if you're designing man-rated systems, you like the big boosters to be liquid fueled because you can turn them off if needed, and in many if not most of the relevant failure modes they'll effectively do that anyway.
And getting back to my point, as echoed by others, none of these equal a launch escape system, a "Get me the hell out of here!" system for when things have gone horribly and irretrievably wrong with the main system.
Particularly unforgivable when it was billed as a boring space truck, when in reality it needlessly ran on the hairy edge in many of its systems. Add the post-Apollo NASA's public works attitude, and we ended up with NASA killing two shuttles and their crews.
In an analysis published in Science that I read, the biggest driver was development cost. SRBs, in fact, the kludge of the big tank, were all done to minimize that, while drastically driving up operational costs, which, of course, were several elections down the road and sort of hidden/not entirely undesired for what had become almost entirely a public works program.
By the same token, I heard first hand from the guy who developed the reentry vehicle that the crazy scheme of Apollo which left us with no operational hardware off the earth was done because it spent "a billion" (8 billion in 2016 dollars) more in Texas, where LBJ just happened to hail from, and back then the race to the moon project was explicitly hailed as a way to spend money in the South and increase its tech know-how.
Read pretty much any SF story about getting to the Moon with chemical rockets prior to NASA, and it involves two transfer stations, one generally manned in LEO, and one in lunar orbit, manning seriously optional.
You use rockets optimized to get from earth to the LEO station, to transfer between the two stations, then one to get to and from the Moon. Cheaper, and you keep long lived and potentially permanent assets up there, anything you loft to LEO is done at tremendous expense, course.
Two flies in the ointment for assets beyond LEO and not under a lot of lunar soil/rock:
Apollo was primarily a political stunt to convince the rest of the world our technology as good or better than the USSR's, who'd we'd let get out into space first to get them to establish the open skies principle that orbiting over someone else's territory wasn't spying (something they were insisting up to a week or month before Sputnik). Such assets were superfluous for the stunt, plus there was a very strong RFK/LBJ prejudice against any hint of military utility in NASA's space program.
That plus internal politics which allocated the initial catch-up job to a group which was only good at making truly impressive launch pad explosions put us on the back foot in terms of getting out into space, and the Soviets made a fairly serious effort to beat us to the moon, e.g. look up the N1 rocket.
Second, and seldom remembered is that the whole program was predicated a quiet Sun cycle, that's the determining reason I've read why the last two missions were canceled, the program had sufficient delays that it was getting into the danger zone, and Nixon wasn't about to kill an Apollo crew.
For some SF coverage of this, read Heinlein's Podkayne of Mars where during an interplanetary voyage all the passengers and crew had to huddle for a while into the small shielded space the craft had for such an event.
I am not sure I would call not building two space stations for the purposes of the program crazy. Remember, that the Apollo program was initiated before anyone had performed an orbital rendezvous of any kind. For quite some time the preferred (by most) approach to the moon landing was direct ascent [0], as rendezvousing seemed just too scary.
The approach of sending a large, but modular spacecraft all the way to the moon also proved to have the ability survive some rather interesting failure modes [1] so maybe it was not so crazy after all?
Remember, that the Apollo program was initiated before anyone had performed an orbital rendezvous of any kind.
And, yet, that became part of the plan rather quickly, it and EVA (extra-vehicular activity) were the big flashy parts of Project Gemini, during which I started following it all in real time.
Apollo used orbital rendezvous for every moon landing. Remember 3 go to moon, 2 land, then 3 come home. Among other advantages this means the lander does not need to drag a heat shield with it.
Knowing little about this stuff, would it not be possible, and preferable, to eject them? Also, how realistic would it be to turn off liquid boosters, as they seem to usually fail with an immediate explosion?
Given the massive thrust they produce, and how close they are to delicate things like the tank, it's hard to imagine a system that could possibly work. It would be exquisitely difficult to get the vectors just right, so they wouldn't bush against the tanks or worse, and even if you pull that off, their exhaust will have bad effects as they pass by.
Short of not using them at all, exhaust ports at the top as mentioned by exDM69 sound like least worst option.
Errr, I should have said "(gently) throttle down", since that's potentially in the menu of options for liquid fueled rockets. What you're talking about sure sounds like an inherently violent deceleration. And the tops of those SRBs are uncomfortably close to the tank and the LOX tank in it at the top....
Dead zones aren't limited to the use of SRBs. For instance, we don't know whether SpaceX will have dead zones or not. I can see one big one in that SpaceX's launch profile is much taller than traditional rockets (more up, less horizontal to aid in recovery of the first stage). A failure of the second stage to ignite may leave the capsule in a place where it won't survive the steep re-entry, falling more vertically than a the normal horizontal albeit faster re-entry. The data needed for such a determination is still hidden behind SpaceX's "proprietary" launch profiles.
If you are moving very fast horizontally you slow in the upper atmosphere and your trajectory, in part, follows the curve of the earth. The net result is that you slow down through hundreds of kilometers of progressively thicker air. On the other hand, if you have no horizontal velocity you are falling like a rock into a much shorter slice of air. It gets much thicker very quickly. Either the capsule cannot survive the force of the thicker air, or it doesn't have enough time to slow down before hitting the ground.
Horizontal re-entry also allows the capsule to 'fly' by trading horizontal velocity for lift, keeping it in the upper atmosphere for longer. That isn't an option when falling strait down.
The comment I replied to was not so much a perspective as a 'feel good' comment, because it was mainly rhetorics instead of actual knowledge and insight.
This is a quick investigation into the 'disaster' and that contrasts with how things normally get investigated, i.e. by big government with findings taking years to see the light of day and with big business and other special interests doing what they can to obfuscate truth and shift the blame onto 'the pilot' (as is usually the way in aviation, car crashes, train crashes and anything else that crashes).
Well done to SpaceX for getting to this explanation, I am so glad this has not been blamed on a sniper hired by their rivals!!!
I understand your criticism but the Columbia Accident Investigation Board released a full report with recommendations for changes 6 months after that accident. Not too shabby.
Right now we have a press release that is pretty thin on details from SpaceX. Not quite comparable.
The solid oxygen that formed could have ignited with the carbon, causing the explosion that destroyed the rocket.
This makes me wonder why the liquid oxygen wouldn't have the same effect? Liquid oxygen is itself an extremely reactive oxidiser (search YouTube videos.)
The carbon fiber and resin are the shell (AKA a straight jacket) over usually a thin titanium vessel.
Carbon fiber alone won't be enough to keep liquid helium at least from precipitating through it, the darn thing can leak through solid glass when it's cold enough.
Not sure about liquid oxygen, but still there is no carbon fiber on the inside of the tank, if nothing else than to ensure that no particulate matter ever gets into the fuel system.
It's just the culture of the time period (late 1960s.) I remember watching some automotive repair videos from roughly the same era, and they would be just as outrageous today.
On the other hand, it definitely makes things memorable.
There's no ignition source normally — the liquid oxygen isn't under as much pressure, it's just sitting in the tank under nominal conditions. The idea is that the solid oxygen formed underneath the top layers of the carbon overwrap. Then as the aluminum liner of the the tank (which is under the composite wrapper) expanded as the tank was filled, the solid oxygen was subjected to enormous pressure, creating the ignition source — right next to a fuel source (the carbon composite), all in a big tank full of oxidizer.
Strange. Their previous failure (CRS-7 blowing up in flight in 2015.[1]) was supposedly caused by a liquid helium tank support strut in the second stage breaking in flight. The liquid helium tank is inside the liquid oxygen tank, so a failure there overpressurizes the liquid oxygen tank.[1]
This second failure again involves a similar liquid helium tank. Not one under flight stress, just sitting there on the pad. Similar failure, though - tank leaks, overpressurizes liquid oxygen tank, second stage explodes.
The Saturn V had helium tanks inside the liquid oxygen tanks, but they were compressed gaseous helium, not liquid helium. Has any other rocket design ever put a liquid helium tank inside a liquid oxygen tank?
Other than the fact that they involved the He tanks, there weren't many similarities between the events.
With CRS-7, there was acoustic evidence of the strut failing and the COPV smacking into the tank wall. With AMOS-6, the first indication of any event was the catastrophic failure of the COPV.
In either case, the location of the He tank isn't terribly relevant... It was going to destroy the rocket either way.
Seems to be caused by the too-cold liquid oxygen interacting with carbon elements. So either change how the tanks are pressurized with helium to prevent the oxygen getting too cold, and/or somehow insulate the carbon from the oxygen better. Neither seem like insurmountable problems.
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[ 0.20 ms ] story [ 153 ms ] threadWhile the loss of the cargo is regrettable, it in no way is as damaging as the loss of 1-3 lived would have been on SpaceX.
So overall unlike humans there is actually pretty low chance for the cargo to survive intact and satellites isn't something you can just fix a dent in, taking it apart doing a full analysis of every component checking for stress, microfractures, and pretty everything else under the sun would probably cost just as much if not more than building a new one.
In this case insurance is pretty much the way to go, especially once you consider the added costs of actually building a LPAS or IFAS for satellites / in orbit release payloads and the fact that they have very little chance of surviving the abort without any damage.
But ITS, the Mars rocket from SpaceX, won’t have a launch abort system. At all.
Although look at the bottom of that link, operationally they've been a mixed blessing, saving one Soyuz crew, but another one wasn't safed after a scrubbed launch and killed a bunch of pad workers.
This stuff is hard, "rocket science" really does deserve its connotations of difficulty, and is inherently dangerous.
Shuttle had launch abort modes. There was a dead zone during SRB burn, but the rest of the assent had planned abort modes for saving the crew.
https://en.wikipedia.org/wiki/Space_Shuttle_abort_modes
Not surprisingly not a single astronaut survived Columbia's depressurization at altitude, because of failure to engage active life support. (A blessing because they had a literal snowballs chance in hell of surviving what followed, but still...)
Shuttle's abort modes, including the bailouts, were premised on the craft being under control. Given the forces involves, if it wasn't under control it probably was about to disintegrate. But the same is true of spaceX-style capsule launches. Whether parachutes would correct a tumbling capsule, or rip it in half, is an open question. They both need to initiate abort procedures at least a millisecond before the craft departs into uncontrolled flight.
(And aborts can be triggered automatically, or by someone on the ground.)
A tumble should be fairly trivial to detect and fire only when the capsule's in its upwards pointing portion of the tumble. Plus, you'd only be firing into the ground if you're pretty early in the launch - the Dragon launch abort only sent it up a kilometer or so. Finally, the launch abort is pretty sensitive - deviating not far off the right direction should trigger it, before a full-on tumble.
Those alone made it a serious death trap, if you're designing man-rated systems, you like the big boosters to be liquid fueled because you can turn them off if needed, and in many if not most of the relevant failure modes they'll effectively do that anyway.
And getting back to my point, as echoed by others, none of these equal a launch escape system, a "Get me the hell out of here!" system for when things have gone horribly and irretrievably wrong with the main system.
Particularly unforgivable when it was billed as a boring space truck, when in reality it needlessly ran on the hairy edge in many of its systems. Add the post-Apollo NASA's public works attitude, and we ended up with NASA killing two shuttles and their crews.
By the same token, I heard first hand from the guy who developed the reentry vehicle that the crazy scheme of Apollo which left us with no operational hardware off the earth was done because it spent "a billion" (8 billion in 2016 dollars) more in Texas, where LBJ just happened to hail from, and back then the race to the moon project was explicitly hailed as a way to spend money in the South and increase its tech know-how.
You use rockets optimized to get from earth to the LEO station, to transfer between the two stations, then one to get to and from the Moon. Cheaper, and you keep long lived and potentially permanent assets up there, anything you loft to LEO is done at tremendous expense, course.
Two flies in the ointment for assets beyond LEO and not under a lot of lunar soil/rock:
Apollo was primarily a political stunt to convince the rest of the world our technology as good or better than the USSR's, who'd we'd let get out into space first to get them to establish the open skies principle that orbiting over someone else's territory wasn't spying (something they were insisting up to a week or month before Sputnik). Such assets were superfluous for the stunt, plus there was a very strong RFK/LBJ prejudice against any hint of military utility in NASA's space program.
That plus internal politics which allocated the initial catch-up job to a group which was only good at making truly impressive launch pad explosions put us on the back foot in terms of getting out into space, and the Soviets made a fairly serious effort to beat us to the moon, e.g. look up the N1 rocket.
Second, and seldom remembered is that the whole program was predicated a quiet Sun cycle, that's the determining reason I've read why the last two missions were canceled, the program had sufficient delays that it was getting into the danger zone, and Nixon wasn't about to kill an Apollo crew.
For some SF coverage of this, read Heinlein's Podkayne of Mars where during an interplanetary voyage all the passengers and crew had to huddle for a while into the small shielded space the craft had for such an event.
The approach of sending a large, but modular spacecraft all the way to the moon also proved to have the ability survive some rather interesting failure modes [1] so maybe it was not so crazy after all?
[0] https://en.wikipedia.org/wiki/Direct_ascent [1] https://en.wikipedia.org/wiki/Apollo_13#Accident
And, yet, that became part of the plan rather quickly, it and EVA (extra-vehicular activity) were the big flashy parts of Project Gemini, during which I started following it all in real time.
The SRBs had a way to turn them off by opening two exhaust ports near the top that would let the gasses out and neutralize the thrust.
But it's still a bit iffy, which is why cryogenic liquid fuels are the most common choice for human-rated launchers.
Short of not using them at all, exhaust ports at the top as mentioned by exDM69 sound like least worst option.
As you say, "a bit iffy", at the very minimum.
Horizontal re-entry also allows the capsule to 'fly' by trading horizontal velocity for lift, keeping it in the upper atmosphere for longer. That isn't an option when falling strait down.
But is it really meaningful for these ‘glass half full’ comments to sit at the top of every single Elon Musk thread?
Well done to SpaceX for getting to this explanation, I am so glad this has not been blamed on a sniper hired by their rivals!!!
Right now we have a press release that is pretty thin on details from SpaceX. Not quite comparable.
This makes me wonder why the liquid oxygen wouldn't have the same effect? Liquid oxygen is itself an extremely reactive oxidiser (search YouTube videos.)
Why would one keep just a layer of hardened resin between all that oxygen and carbon? Seems like an accident waiting to happen.
Carbon fiber alone won't be enough to keep liquid helium at least from precipitating through it, the darn thing can leak through solid glass when it's cold enough.
Not sure about liquid oxygen, but still there is no carbon fiber on the inside of the tank, if nothing else than to ensure that no particulate matter ever gets into the fuel system.
https://www.youtube.com/watch?v=rUKcHe0-m_I
I am like 90% sure that they filmed that as a 70's porno movie and just cut out all the "interesting" parts out to make this instruction video....
Case and Point: https://youtu.be/rUKcHe0-m_I?t=175 (same video just a time stamp at 2m 55s) potentially NSFW....
But honestly what drugs were the guys on when making this, and how the hell was this ever accepted by the USAF?!
On the other hand, it definitely makes things memorable.
This second failure again involves a similar liquid helium tank. Not one under flight stress, just sitting there on the pad. Similar failure, though - tank leaks, overpressurizes liquid oxygen tank, second stage explodes.
The Saturn V had helium tanks inside the liquid oxygen tanks, but they were compressed gaseous helium, not liquid helium. Has any other rocket design ever put a liquid helium tank inside a liquid oxygen tank?
[1] https://www.nasaspaceflight.com/2015/07/spacex-falcon-9-fail...
With CRS-7, there was acoustic evidence of the strut failing and the COPV smacking into the tank wall. With AMOS-6, the first indication of any event was the catastrophic failure of the COPV.
In either case, the location of the He tank isn't terribly relevant... It was going to destroy the rocket either way.