Ask HN: Which re-entry/de-orbit was this?

34 points by krmblg ↗ HN
Hi HN!

With the CZ5N re-entry happening I figured you could point me in the right direction to solve this mystery:

On the evening of july 14, around 20:15 UTC we saw something pass over our heads fairly slowly (apparently stationary), leaving a greenish, sparkly line over the course of several minutes. It also left a long trail that apparently was still illuminated by the sun, originating at an azimuth of ~210° (SSW).

Our observation position was ~48.08° N, 11.28° E (southern Germany, near Munich).

About 20 minutes later I tried digging into it a little on James Darpinian's See A Satellite Tonight and found a rocket/booster stage that could have had a matching trajectory (CZ-4B R/B).

I'd love to dig deeper into this, so:

1. Are there any websites where I can revisit that time/location? I'm aware of TLEs but would appreciate a "time-travel" view for the location in question

2. The CZ-4B R/B still seems to be „around“. Is it likely that we saw re-entry of only smaller parts of it that were just low enough to "hit" a substantial amount of atmosphere?

3. Are there other explanations for a slow-moving object leaving a trail creating greenish, sparkly lines?

4. What additional information would be needed to figure out what happened?

Any help is much appreciated!

9 comments

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Five days earlier a 10-foot piece of space debris crashed in Australia - the largest one since SkyLab.

https://www.newsweek.com/huge-piece-space-rocket-falls-sky-l...

It's probably unrelated -- but there's the possibility that an even larger object had split into two chunks, with one hitting Australia and the other taking an additional five days before its orbit decayed.

Of course no response from the faceless corporation dumping lethal space junk on people’s properties.
Probably because it's not yet known which entity is responsible despite what has been posted on social media.
It looks A LOT like a piece of spacex dragon capsule's jetisoned trunk that was intended to fall into the sea between Australia and New Zealand. This debris was found just a short way earlier on its trajectory so seems clear to me that spacex was aiming for a controlled reentry and it went in just a little bit early. This likely due to fluctuations in the upper atmosphere but spacex should have left larger margins for error.
This sort of thing tends to be resolved privately with the landowners involved rather than publicly.
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