Space

8727 readers

4 users here now

Share & discuss informative content on: Astrophysics, Cosmology, Space Exploration, Planetary Science and Astrobiology.

Rules

Be respectful and inclusive.
No harassment, hate speech, or trolling.
Engage in constructive discussions.
Share relevant content.
Follow guidelines and moderators' instructions.
Use appropriate language and tone.
Report violations.
Foster a continuous learning environment.

Picture of the Day

The Busy Center of the Lagoon Nebula

Related Communities

🔭 Science

🚀 Engineering

🌌 Art and Photography

Other Cool Links

founded 1 year ago

MODERATORS

[email protected]

124

SpaceX’s Starship rocket completes test flight for the first time, successfully splashes down (www.cnbc.com)

submitted 5 months ago by [email protected] to c/[email protected]

13 comments fedilink hide all child comments

you are viewing a single comment's thread
view the rest of the comments

[–] [email protected] 8 points 5 months ago (1 children)

I expect the flap on the opposite side of the ship experienced a similar level of destruction. Well, that depends on whether the damage occurred because of a general loss of structural integrity because of excessive heating, or if specific localized damage on that flap allowed plasma to penetrate the heat shield, resulting in the damage that we observed. So, general structural failure vs. random damage at that location cascading into a hole in the flap.

Anyways, I am pretty sure that the complete loss of control authority on one of the flaps would be catastrophic. But the movement that we observed seemed pretty deliberate and consistent to what we saw during the suborbital test flights. Especially the unfolding of the flap at the T+01:05:42 mark is EXACTLY what we saw during the high-altitude flights, e.g., see SN8 @ T+6:33 or SN9 @ T+6:18. The forward flaps are folded back at first, and then rotate into a position perpendicular to the surface of Starship. The movement (for IFT-4) is precise, consistent with previous flights, and stops abruptly in the correct position.

[–] [email protected] 6 points 5 months ago* (last edited 5 months ago) (1 children)

True, but it was definitely broken by the time the landing burn commenced. So it's hard to see where it failed. I think the other fins must have done much better, otherwise it would have totally lost control. The telemetry did get weird at one point, but it's hard to say if that was just an error in the data or actually happening.

Note that besides the fins they added more cold gas thrusters this time, so a loss of one or more fins wouldn't mean loss of control like with the previous attempt.

I also think the connection between the fin and the inside didn't fail and held up well. I remember from Space Shuttle that a small defect in the heatshield meant a stream of superheated air blasted in like a plasma cutter and destroyed the insides, even in parts where the heat shield was just fine. But with this flight on Starship it seamed like the fin burned away, but the inside was fine, otherwise I think it would have blown up. It even seamed like the fin moves after a lot of it was burned up, so that would mean the motors and control systems were still working. But I'm still not sure at what point it failed, some of the movement could be due to atmosphere with it hitting the end stops, so it looked like a controlled movement to a certain point.

Very interesting and cool nonetheless.

[–] [email protected] 3 points 5 months ago

I just compared the footage from various points in time. The flap positions for T+00:48:12 (pre-entry) and T+01:05:41 are almost the same, then it rotates about its rotation axis until T+01:05:44, but suddenly it starts to rotate about ANOTHER axis, and at T+01:05:47, its at a completely new angle. I think T+01:05:44 is the point where the flap finally breaks (after touchdown, but before splashdown).

I think we have seen motion as fast as the one at T+01:04:22, but the subsequent bounce is surprisingly strong. I still think that the flap was still under some control at that point.

I heard rumors on reddit that SpaceX deliberately removed a single tile on this flap for testing purposes, but I could not find any reliable confirmation for this. They deliberately removed tiles on the engine skirt, though.