I have yet to see an authoritative explanation for why the attempt to recover
Booster 13 with the chopsticks was called off, but with the exception of not
getting the dramatic, semi-addictive video of the chopsticks catching the
Booster it looked to be quite a successful flight test. (I've probably
watched videos of capturing the booster on flight test 5 over 30 times)
Last night, Igor commented that,“Unconfirmed rumor has it there was a malfunction on the tower. Stay tuned.” I watched a video that Scott Manley released early this morning and while not very specific, he puts up some information that agrees with that synopsis. I expect we'll get a more thorough answer in a day or two.
The emphasis in this mission was on the Starship, that had been extensively modified, especially in the heat shield. During the SpaceX video stream, one of the Engineering Managers who often narrates those presentations gave some impressive details.
Kate Tice, a SpaceX engineer hosting the company's live broadcast of the mission, said teams at Starbase removed 2,100 heat shield tiles from Starship ahead of Tuesday's launch. Their removal exposed wider swaths of the ship's stainless steel skin to super-heated plasma, and SpaceX teams were eager to see how well the spacecraft held up during reentry. In the language of flight testing, this approach is called exploring the corners of the envelope, where engineers evaluate how a new airplane or rocket performs in extreme conditions.
2,100 heat shield tiles? It wasn't so much to reduce weight (every tile takes up some of the payload capacity of the ship) but to check how specific areas of the Starship's skin handle the searing heat of reentry. In that Scott Manley video, he shows some areas of the exposed skin and how the few thousands of degrees the reentry brought had some of the steel apparently buckling. Yet another reason to use stainless steel instead of aluminum or carbon fiber. As the heat eased, the stainless just shrugged it off and returned to the original shape.
Many of the removed tiles came from the sides of Starship where SpaceX plans to place catch fittings on future vehicles. These are the hardware protuberances that will catch on the top side of the launch tower's mechanical arms, similar to fittings used on the Super Heavy booster.
"The next flight, we want to better understand where we can install catch hardware, not necessarily to actually do the catch but to see how that hardware holds up in those spots," Tice said. "Today's flight will help inform 'does the stainless steel hold up like we think it may, based on experiments that we conducted on Flight 5?'"
The Space Shuttles had lots of issues with tiles and had a problem that certain tiles could only be used in some places. I've read they practically had only one tile that worked for any specific spot on the shuttle complicating repairs and refurbishment between missions. SpaceX uses identical hexagonal tiles as a general rule, although it seems to me they must have some tiles that only work in a specific place, or families of tiles for specific places.
Integrated Flight Test 6, seconds after launch. Image credit: SpaceX
You might have seen some photos of Elon Musk with a group of VIPs he hosted
for the launch, including President-Elect Trump, Ted Cruz, RFK Jr., Donald
Trump Jr. and more. A person I didn't recognize was General Chance Saltzman,
the U.S. Space Force’s chief of space operations. This is being taken as a
sign that Space Force is interested in what the world's biggest and most
powerful rocket could do for them.
The important tests on Starship have all been reported as passing
successfully. Proving the Raptor engines can re-ignite in orbit was an
important milestone in Starship development. After the mission, Musk said
they'd do one more Starship landing in water and would try to catch the ship
with a launch tower on the 8th flight. It's debatable when IFT-7 will be but I
think it could be before the end of this year. IFT-8 then, figures to be
in the first quarter of '25.
The booster, while still being improved upon, is going to take a back seat to the Starship itself, as the whole shebang's purpose is to... wait for it... Get Stuff To Orbit.
ReplyDeleteNow, one of the exciting things is going to be the ability to bring down (intact!) stuff from orbit and elsewhere. THAT'S going to be extremely useful, but so is the ability to haul bigger and heavier things to orbit. No more overstuffing origami space probes and satellites into a cramped shroud even though so far amazing things have been done!
So, I'm starting to get real excited with the Starship, can't wait until it's caught. We can parallel park the booster, now lets do the ship.
Go SpaceX!!
That 304L alloy SpaceX employs is truly fantastic material, one of those marvelous just right blend of alloying agents, producing wonderful characteristics, a similar example metal is 4130 Chrome Moly steel, which also has excellent weldability, yield and tensile numbers, workability too is an important attribute.
ReplyDeleteHad a custom race exhaust business spanning a couple decades, over that time the systems I fabricated, almost exclusively, in 304L mandrel bent tubing, to my knowledge never failed due to material issues, (provided a lifetime warranty with my ex systems). Something about 304 which is to me very interesting, and that is its capability to return to normal state after pretty high temps, talking upwards of 1800-2000 degs F, its ability to hold its shape at said temps, not just that, 304 anneals upon cooling to ambient, just a great metal alloy all around. Its my experienced personal opinion SpaceX really chose the best material for building their spacecraft out of. An aside is 304's excellent scrap metal value, it can get pretty high at times, over $300 per hundred weight, though it may not be a big factor, still with all the scrap 304 they produce I imagine they can pretty much pay for, at least, their scrap yard operations, probably even go highest bidder route. That probably adds up over the long run, in particular as they ramp up building SuperHeavy like they are talking about.
Thanks for that. I have some knowledge of the materials they use but not that kind of detail. Hobbyist vs. professional levels.
DeleteWhile I think I remember SpaceX switching from the more conventional idea of a carbon fiber Starship over to stainless, I can't find it searching the blog. It was before the days of test flying Hoppy so way before the first Starship tests.
They gave up on CFRP based on a Musk decision. They were testing tanks. Here is one article from 2016:
Deletehttps://www.cfpublic.org/2016-10-24/elon-musk-reveals-more-mars-details-fuel-tank-test
Per Elon Musk, the booster was diverted to a water landing because communication with the tower computer was lost. They will have that fixed by IFT-7. Hope to see another booster catch then. IFT-8 may be a booster and starship catch event with the ship doing orbits before returning.
ReplyDeleteSpaceX had a FB post saying that they lost comms with the tower, so in an abundance of safety, they diverted to the ocean.
ReplyDeleteIs "Mostly Successful" like "mostly peaceful" or is it more like "mostly dead?"
ReplyDeleteI was thinking of those scenes from the riots of '20, "mostly peaceful" as fires burned all around the reporter, but doesn't really describe the mission. It was really almost entirely successful, and as the previous comments say, the real issue that caused them to land the booster in the Gulf was a problem with the launch mount. There are pictures that show something on top of the tower bent about 20 degrees off vertical, as if something hit it. If that was the antenna mast, that could explain it.
DeleteFor want of a nail.
DeleteSince Tuesday I have been thinking that IFT-6 should have had some redundancy in landing systems. And now, for something as simple as an antenna mast askew, the booster was lost.
I reckon that might be the old way of looking at it. The Space X way is that the only failure is not capturing the data. So, even with the booster not landed as intended, and sunk into the sea, the mission was a success because the data returned.
It seems like Space X is a cyber company that also does rockets
Delete