Sunday, November 19, 2023

What Became of Starship S25?

While it's just over 36 hours since the test flight 2 launch Saturday morning as I write, and it's a weekend night which means official news is going to be few and far between.  I suspect that like many of you, I've been trying to find anything that looks to be realistic and reasonably coherent about the details of what is known about test flight 2.  

Some of what's presented here will be reposts of things I've posted before.  The first is this: among the first questions people started asking was if the new water deluge system saved the orbital launch pad.  By mid-afternoon Saturday, Elon Musk was saying they had driven out to the launch pad and there was no damage worth mentioning. Tweeted here.  Jack Beyer, Content Manager and photographer for NASA Spaceflight  tweeted essentially the same thing, adding something like, "now that's a rapidly reusable launch pad!"  

The loss of the booster after it's actual flight performance, which was insanely better than the first flight test, gets talked about a lot.  I think minimizing the booster's performance over that is mistaken.  It's important to recognize that SpaceX had never before successfully ignited all 33 Raptor engines at once on a Super Heavy booster stage.  All 33 lit and stayed lit for the entire duration, while producing the largest mach diamond ever seen (it is the largest vehicle ever launched, after all).

The interesting thing about the hot staging that I didn't see talk of until this afternoon shows up in this SpaceX video.  You can watch the three sea-level Raptors carefully, the innermost three, and see that when you can first see all three, 11 seconds on the clock, they're all pointed as far away from center as they get. By the 14 second mark they're all pointed on axis, to maximize thrust, which is no longer pointed at the top of the booster.  I created this image from video frame captures to show what I mean. 

You can clearly see the three flames are much farther apart on the left, at about 11 seconds, than on the right, which was closer to 14 seconds.  That seems intended to minimize the amount of time the engines are blasting the top of the booster.  The booster was lost several seconds after this.

Something that I've seen little mention of is analysis of just what happened to Ship 25.  A video I saw on Saturday implied that it must have been down range quite some distance, and since we had a good idea of its altitude, they had derived that it must have been in Atlantic, after having flown over the Florida Straits between the Keys and Cuba. Astronomer Jonathon McDowell posted this to X Saturday morning ET.  A NOAA weather radar detected the debris from Ship 25 falling along its trajectory into the Atlantic.

The longitude and latitude markers along the edges of the picture allow me to pin point this location on a hurricane tracking map.  At the bottom left of the picture, there's a land area with what appears to be light rain, or possibly clutter, over its eastern side.  That land mass is Puerto Rico.

There is talk about a picture that shows the nose of Ship25 from the top down to the bottom of the first two flaps, that somehow survived whatever happened, but I haven't found that picture.  Yet.  Hopefully, SpaceX downloaded telemetry that allows them to reconstruct the story. 


  1. I saw the picture you are talking about. A commenter over at Behind the Black posted a link to it. It appears to be the part of the Starship ahead of the top propellant tank. That would make sense that the LOX/LCH4 tanks destructed but not the forward section.

    The relevant picture is at about 17:08 into this video from

    Starship Explosion Footage From The Florida Keys

    1. Thanks for that, Bill!

      I had seen that video in my YouTube feed and thought I should watch it, but didn't have much hope I'd find it. Just watched up to about the 25 minute mark. Time to go watch more.

  2. There was an amateur video of somebody in Puerto Rico (?) that showed large chunks of Starship burning up during reentry, Can't find it now. If I do I'll annotate this comment.
    People in the know such as Scott Manley theorize fuel slosh or fuel hydraulic hammering may have done in the booster along with the engines, and he also showed the O2 levels dropping rapidly just before AFTS blew the Starship. That would be reasonable if the S25 had some major damage/fire/rupture problem.

    Now we wait for SpaceX and FAA to issue a report on what went wrong.

    All in all, an extremely well second test, lotsa data available, and you can bet they'll be working on that staging which has a large probability of causing the problem!

    Those Mach diamonds were awesome, as well as the length of the exhaust plume and the shock waves when they lit up that monster. I can hardly wait for IFT-3!!


    1. I've tried to find that video from Puerto Rico but no joy so far. It's the ground-based view of that radar capture above.

      Yesterday, Musk Tweeted (Xeeded?) that the next flight "should be ready to fly in 3 to 4 weeks," according to today. It's looking to be booster 10 and ship 28 from what I'm reading around, but they're so "hardware-rich" that their meetings must be like "which pair do you want to launch this time?" ... "I don't know. Which pair do you want to launch?"

      Of course, SpaceX doesn't say they can fly in December. That has to be the FAA.

      Eric Berger at Ars Technica did a very favorable article about the test flight today, saying that as of now, Starship is as successful as NASA’s SLS rocket.

  3. With regards to the Mach Diamonds formed during the launch, I thought that this article might be of interest:

  4. There is a stabilized video from a private ground camera (lost the link) that shows Ship25 tumbling and rolling but still structurally holding together while venting burning gases for some time, maybe 60s.

    I think this is actually the first serious failure that I know of for IFT-2, the 2nd stage FTS … didn’t.

    Brownsville/Matamoros are only a few miles away, a Starship weighing as much as a 737 could conceivably reach there after a lower atmosphere booster failure just by gliding, even with the l/d of a brick.

    The FAA is going to want answers and a solution.

  5. I found the link, it is a video from astronomy live on YouTube, filmed from the Florida Keys:

    1. Just got back from my Thanksgiving road trip or I would have replied to the 12:41AM comment that I had posted the link to that in Tuesday's post, the one about the Psyche mission that also included a paragraph at the bottom about S25. I apparently screwed up by just using a one word link ("here") rather than several words or a complete sentence. My wife didn't notice that link either.