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Laremere 6 hours ago

Summary from my watch:

- Launch roughly on time, after a scrub yesterday. (Sounds like the scrub was due to ground equipment, most notably the water system.)

- Initial ascent was good, but then one engine on the booster went out.

- Relight of the booster's engines after stage separation for the boost back burn failed. Engines did light again for a landing burn, but seems to have hit the water harder than expected and was very off target.

- Starship lost one engine shortly after stage sep. Turned into an unintentional test of engine out capability. It made it to space.

- Some weird motion and lots of off-gassing after engine cut-off, with uncertainty about if it actually got a good orbital(ish) insertion. Seems to have been benign, with the motion being a weird slow flip to the orientation for payload deployment.

- Test deployment of dummy payloads was successful, including a couple with cameras to look back at Starship.

- An in space engine relight test was skipped, presumably due to the issues during launch.

- Re-entry to over the Indian Ocean seemed to go really well. Nothing obviously burning or falling off. The amazing views of the plasma during re-entry, something never seen live before starship, are now routine.

- Starship did a maneuver to simulate how they'll have to go out over the gulf and back to the landing site.

- Nailed the target, evidenced by views from drones and buoys. Soft landing before falling over and giving us a big (expected) boom.

As far as overall progress from previous test flights goes, they're at least treading water while making many large changes. I think they were hoping to try for a tower catch and actually going orbital for next flight, but I highly doubt that now. The boostback burn failing was the largest failure, with the engine failure on Starship being a close second. Good performance despite engine out seems to be an unintentional success.

ChuckMcM an hour ago | parent | next [-]

Nice work by SpaceX engineering.

Good summary. The booster appeared to hit the water at 1400 km/h (a bit under 900 mph) so not really survivable :-). Engine out on ship seems to left them with just enough fuel to land but not enough to do the hover thing (simulates being caught by chopsticks). They notched it down to two engines (vs planned 3) on the landing it seems?

Basically if they can figure out the engine issues, it looks like they should be able to do a full end to end flight. That's reasonable progress. Given the IPO this was a pretty important flight and I don't think they hurt it (like blowing up on the launch pad would have). So their one step closer it seems.

rogerrogerr 2 hours ago | parent | prev | next [-]

“seems to have hit the water harder than expected and was very off target.”

SpaceX’s people were saying it was on target, and it seems to have landed in about the same position relative to the camera buoy as previous flights. I don’t think there’s any evidence to call it off target. The landing and toppling looked the same as previous flights too.

zardo an hour ago | parent [-]

You've mixed up the ship and booster.

irjustin 4 hours ago | parent | prev | next [-]

The videos were incredible. My favorite part was watching the booster flip in such clarity. Normally we don't get full view of it, let alone 4k.

globalnode 2 hours ago | parent [-]

The videos are great!, but the rest of it is never going to work lol, just never. Even without a rethink about how to get heavy payloads to another planet this is still good entertainment.

itsthecourier 2 hours ago | parent [-]

why won't it ever work?

globalnode 2 hours ago | parent [-]

Even if it landed perfectly how is it going to be rapidly reusable with all those tiles breaking and needing repair? Then if that problem was magically engineered-away through some sort of materials science breakthrough, it still makes more sense to me to keep your big ships in a space staging area and your smaller ones as atmospheric gophers.

s1artibartfast 24 minutes ago | parent [-]

Small ships are less efficient. Thats the whole point

GMoromisato 3 hours ago | parent | prev | next [-]

Good summary. I was pleasantly surprised that they nailed the re-entry target even after the ascent engine problems.

The re-entry itself looks amazingly smooth compared to V2. TBD whether it's good enough for re-usability (much less rapid re-usability).

But Flight 12 was definitely forward progress.

SJMG 4 hours ago | parent | prev | next [-]

I'm concerned about the cracking clearly visible on the heat shield tiles. It doesn't bode well for rapid reusability.

WalterBright 4 hours ago | parent | next [-]

I thought the tiles were designed for easy replacement, so not a big concern with replacing cracked ones.

EA 3 hours ago | parent | prev | next [-]

The tiles ablate. The shuttle returned from every mission with missing tiles.

jordanb 3 hours ago | parent | next [-]

Shuttle's tiles not being durable as hoped is what killed it's turnaround time.

The problem was never solved and turned what was supposed to be a few days into weeks or months. Every mission the shuttle had to go back into the assembly building and have all tiles inspected and potentially replaced.

dnautics 3 hours ago | parent [-]

Shuttle tiles were also unique per position and starship tiles have a few base forms that are interchangeable

amluto 2 hours ago | parent [-]

I would also believe that a robot could inspect and replace tiles a lot faster than humans.

sidewndr46 3 hours ago | parent | prev | next [-]

Well, every mission that it returned from it had missing tiles. That is not the same thing as returning from every mission.

throwaway85825 3 hours ago | parent | prev [-]

The shuttle required long expensive refurbishment after each flight.

b112 an hour ago | parent [-]

Just made me realise, this is just like the F-35.

Its turn around time is ridiculous, it has to be maintained with specialized equipment/hangers, along with external contractor assistance.

Compared to the Gripen, as an example, which can land on a freeway and be up in the air again in a few minutes.

One was designed to be used in war, in desperate scenarios, with no ability to coddle it. The other, the F-35? Is designed around milking the taxpayer as much as possible, and employing people in as many politician's states as possible.

The shuttle was like that, I think. Which is really sad.

simmonmt 4 hours ago | parent | prev [-]

I mean ... step 1 is probably fixing the part where it lands in the ocean, falls over and explodes. Once they've done that and can get their hands on the tiles I'm guessing they can continue to iterate there until they get a more easily reusable design.

shigawire 3 hours ago | parent | next [-]

That part was intentional

idiotsecant 2 hours ago | parent | prev [-]

Dang, a random HN user solving all the world's problems yet again, what would humanity do without you random HN guy?

clippy99 3 hours ago | parent | prev | next [-]

SpaceX does an excellent job at videography. Sad that Nasa flew its Artemis mission with potato cameras.

SV_BubbleTime 3 hours ago | parent [-]

Hey, we have everyone watching, our funding might in part depend on interest and awe…

Not just space-potatoes… but missed the separation shot on the live feed. How in the hell!?

TechPlasma 5 hours ago | parent | prev | next [-]

I think the ship really punted the booster during stage separation. And caused the boost back failure from sloshing.

Also I think Ship now has methane thrusters on it. They were operating with a clean blue flame in short purposeful bursts.

generuso 5 hours ago | parent [-]

If we look at the venting from the propellant tank (around T+16:15) it looks thick white closer to the vent, becoming more transparent and blue as it expands. That's just sunlight scattering on the particles and density fluctuations in the flow.

A good cold gas thruster produces a lower density, more expanded flow, which looks blue for the same the reason the sky looks blue.

One can compare this to the exhaust from various Falcon-9 engines and thrusters when it is illuminated by the sun on the backdrop of the night sky: https://youtu.be/JRzZl_nq6fk?t=193

russdill 3 hours ago | parent | prev | next [-]

The final issue that led to the scrub was that a pin that held back the QD arm got bound and would not release.

dylan604 3 hours ago | parent | prev | next [-]

Did the landing burn light two engines as expected? It happened fast, but the graphic made it look like only one lit. If that’s true, that would be impressive as only lighting two was meant to be a test. At least according to the live stream hosts.

jordanb 3 hours ago | parent | prev | next [-]

> The amazing views of the plasma during re-entry, something never seen live before starship, are now routine.

The word "live" is doing a lot of work here. Astronauts used to film the plasma going past the windows of Shuttle.

I remember as a kid my science textbook had a still of it to illustrate plasma.

dingaling 2 hours ago | parent [-]

> The word "live" is doing a lot of work here

A latency of a few seconds for streaming video compared to several months for a still photo from the Shuttle seems an entirely valid use of 'live'.

aaron695 4 hours ago | parent | prev | next [-]

[dead]

SilverElfin 3 hours ago | parent | prev | next [-]

Lots of engine failures. Doesn't exactly bode well for a company looking to go public immediately. One of the engine failures was not on the booster but Starship as you noted, and that is a bit unexpected. I don't think they have spoken about it being equal in capability with one engine out, right? Those engines don't move around to compensate IIRC.

dylan604 3 hours ago | parent [-]

Not sure how you come to that conclusion. The capabilities can overcome loss of engines. The fact it was successful with loss of engines shows it is working as designed.

SilverElfin 3 hours ago | parent [-]

No, it just means the mission happened to be salvageable because of its parameters. The booster is designed to have engines out and can compensate because it has so many engines and many of them are on gimbals. On starship, the vacuum engines aren’t on a gimbal. I’m not sure how it could compensate for one of three engines being out.

rdtsc 2 hours ago | parent | next [-]

Some are on a gimbal and they specifically talked how others gimbaled out a bit to compensate. This is specifically something they designed in and not an accidental lucky save. In this flight they didn’t intend to test “one engine out” feature but it worked out that way.

SilverElfin 2 hours ago | parent [-]

See my other comment. The vacuum engines are NOT on a gimbal. None of them. The sea level engines on starship and several of the engines on the booster are on a gimbal. But not the vacuum engines for space.

EDIT: I cannot reply further in this thread, but my understanding is that the non vacuum engines are not intended to stay lit throughout the orbital flight in a typical mission. If they are, they can gimbal and compensate.

rdtsc 13 minutes ago | parent | next [-]

> The vacuum engines are NOT on a gimbal. None of them

I said some raptor engines are on a gimbal, not vacuum engines.

To be precise, the three central engines can gimbal up to 15 degrees. That can control the thrust vectoring when an engine fails, and that’s what happens in the last flight.

Since the flight already happened and we know it didn’t spin out of control (unless you imply their diagnostic and telemetry was completely off and the engine was actually on) something must have compensated for the failure. It wasn’t magic, it was in fact the central 3 engines that did that.

You may be confused because those are called sea level engines, but that doesn’t mean they can’t work in vacuum.

adgjlsfhk1 an hour ago | parent | prev [-]

I think previous comment means "on a gimbal" as in "angled at a non completely prograde direction" (presumably angled such that each engine points through center of mass so that none of the engines impart a torque)

labcomputer an hour ago | parent [-]

The person you’re replying to is trying to play rhetorical word games.

The upper stage has six engines. The outer three engines are “vacuum engines” (optimized for operation in space). The inner three engines are “non vacuum engines” (optimized for operation in the atmosphere, at sea level).

The outer three vacuum engines are not gimbaled, but the inner three sea level engines are. Thus, it is completely accurate to say that they gimbaled some of the engines to compensate for the engine failure.

echoangle 3 hours ago | parent | prev [-]

They explicitly said that they have engine out capability on the ship in the stream.

SilverElfin 2 hours ago | parent [-]

That’s for the booster (the big lower part) not for starship (the upper part that continues to space). They were surprised to have a vacuum engine out. In space there’s no atmosphere so you can’t use fins or wings to change direction. And if the engines can’t move around, you only have thrust and gravity and the tiny attitude adjusters to direct your ship.

cwillu 35 minutes ago | parent [-]

You're simply wrong. The non-vacuum-optimized engines on the upper stage are still functioning in a vacuum, and their ability to gimbal to offset the loss of one of the vacuum-optimized engines was planned for.

stephc_int13 5 hours ago | parent | prev [-]

The takeoff looked almost normal but I noticed a slight drift from vertical, likely because one of the engines was dead or dying. Overall the V3 is supposed to be an upgrade but actual progress is more or less stalling compared V2.

Laremere 4 hours ago | parent | next [-]

It is supposed to tilt away from the launch tower immediately, you can see this on previous flights. This keeps the engine plume away from the chopsticks and top of the launch tower.

irjustin 4 hours ago | parent [-]

Also an additional goal is to get the booster as far away from the pad as immediately possible in the event it falls back down.

signatoremo 3 hours ago | parent | prev | next [-]

The payload (100t) is at least double that of previous flights. It’s largest spacecraft ever flew. That’s some stalling

SilverElfin 3 hours ago | parent | prev [-]

There is a slight tilt normally, but I agree it was more than usual.