A Flawless Dragon Landing
Today’s successful splashdown of the @SpaceX Demo-1 #CrewDragon capsule after its mission to @Space_Station marked another milestone in a new era of human spaceflight. @Commercial_Crew is one step closer to launching American astronauts on American rockets from American soil. pic.twitter.com/9THTVlubiA
— Jim Bridenstine (@JimBridenstine) March 8, 2019
It’s pretty cool, although I wish NASA would pay for testing propulsive landings on dry land as well.
Apparently, they don’t like the idea of having components that punch through the bottom of the TPS shell. After SpaceX calculated the cost of re-applying the SPAM every flight, Elon wasn’t too keen either.
That makes sense.
Thank you for the explanation. I had forgotten the reason for the water mandated landing.
The TPS seems to be a combination of tile and SPAM. I would expect SPAM would have to be reapplied (by its very nature), and it appears that the tiles can’t be reused after immersion:
https://www.reddit.com/r/sp…
so it would seem that water landing or not, the TPS has to be replaced after every flight.
That’s two things you made me look up.
First, the PICA-X actually can be called tiles. I thought you were wrong, because “tile” made me think of the Shuttle’s ceramic tiles. PICA isn’t a ceramic. I which is worth mentioning because that makes it much more robust. (By the way, does anyone know why NASA is spending a fair amount on developing its own improved version of PICA, rather than just licensing the version 3 PICA-X from SpaceX?)
Second, SpaceX Proprietary Ablative Material or SPAM? Really? And people claim NASA comes up with contrived acronyms. I’ll admit some people Cassini project did actually got into a competition for silly acronyms and we did have SPAM. But it cause a few problems for email filters (imagine a serious email asking if you’d read the SPAM that was sent out last Friday…)
Elon Musk does like to have his fun, like sending a female mannequin on the maiden flight of the Dragon2.
Sure. But the mannequin was much better. I just realized it how much better. Named after Ellen Ripley and landing on International Women’s Day (ok, not in all time zones…) That’s not a bad touch, even if it was coincidental.
Maybe Starship willwill retr Starman, then he and Ripley can get hitched on the Moon?
/jk
Since the sides of Dragon 2 have protrusions for the Dracos, you would think they could flare out the sides between the Dracos to put extendable legs there and avoid punching the heat shield.
That’s what I thought as well; but this spacecraft already has stability issues caused by the fact it’s not symmetrical. Perhaps your idea would exacerbate this problem (I’m not saying this is the answer…)
Quick question: why did Space X went for an unstable profile for the shield? or is it the whole capsule? is it for lower g’s at descent?
That’s a tough call. Adding more asymmetries actually can make something more symmetric. One structure at one location is very asymmetric. Four identical and evenly spaced ones is better. In the extreme, 360 identical structures, one per degree, would be very much like a really symmetric vehicle. Eight structures of different sorts (thruster clusters and landing gear), compared to four identical ones? That’s and interesting engineering problem. My gut feeling is that would take some serious analysis and design work. The change could make stability better or worse, depending on the details.
I was wondering why space x will go for a non-symmetrical shield?
Let’s not propagate false rumors, that is not why propulsive landing was cancelled.
The actual reason, communicated by insiders on NSF, is NASA is terrified by propulsive landing since nobody has ever used it before, so they asked for tons of tests. They also forbid SpaceX from testing propulsive landing using cargo missions, this means SpaceX will need to perform real launches in order to fulfill NASA’s test requirement, the cost would be way too high.
Heat shield penetration is never a concern, remember Shuttle has them for the landing gears, Dream Chaser will have them too.
Speaking of rumors. Heat shield penetration was the stated reason for dropping propulsive landing. Those were, if memory serves, statements from NASA and SpaceX quoted in multiple, reliable news sources. For your “actual reason”, you’re citing anonymous statements on an internet blog.
Please don’t misunderstand me: I suspect there was more to it than heat shield penetration. I also suspect propulsive landing scared some conservative engineers. But I can’t honestly call those suspicions a fact and dismiss the official statements as rumors.
I’m fairly sure there’s no official NASA/SpaceX explanation for cancelling propulsive landing. The only explanation we got is from Elon Musk in ISDC 2017 keynote Q&A, this is where all the news sources based their story on. You can hear his answer and judge for yourself: https://www.youtube.com/wat…, after 1 hour 4 minutes mark.
I think it’s pretty clear he talked about two related but different things:
1. They cancelled propulsive landing, and deleted the landing legs
2. The reason for cancellation is two fold, it’s hard to qualify this for flight, and the landing method is no longer what they wants to use on BFR.
News outlet and some folks got cause and effect mixed up and thought the deleting the legs is the reason for cancellation but in fact it’s the result of the cancellation, it’s just Elon stated the effect first and cause later.
This issue has been described a couple of times at arstechnica.com.
Next stop DM-2 and Soyuz facing the cold, hard winds of competition.
The next stop will be the Inflight Abort test, hopefully in a few weeks using this same capsule, IF NASA is able to get its paperwork turned around quickly. Hopefully since it was a “textbook” flight they will do so.
That said, wouldn’t it be great if DM2 took place on July 20th to celebrate the 50th Anniversary of Apollo? Wouldn’t that be a great way to start a new era in HSF?
“wouldn’t it be great if DM2 took place on July 20th to celebrate the 50th Anniversary of Apollo? ” – I cannot adequately express my approval of such a feat without using language that would get me banned. 😉
Congratulations SpaceX! Now let’s get through the Max-Q abort test, and start flying people! Then U.S.A. is back in people-launching business and the Russians can go…fly a kite!
Or jump on a trampoline.
Go SpaceX Go! Next up will be their launch of the upgraded Falcon Heavy.
I’ve lived in southern Florida nearly 40 years. In that time, I have watched dozens of flights, involving all kinds of spacecraft, STS, and of course Apollo.
Still, something about SpaceX gets me all goofy.
Nothing to date quite matches Apollo for me, but that Falcon Heavy launch with dual booster landing came closest.
Congratulations to SpaceX! One step closer…
Meanwhile, in other news, our own Peggy Whitson is back, now having accumulated 665 days in space.
A fine day indeed.
? Her last flight was in 2017 and she retired from NASA last year…
Yes! Of course you are right. No idea how I got those wires crossed (particularly involving Ms. Whitson, a special hero of mine).
Thanks.