SpaceX Starship development: fifth flight, captures booster

[berkeman]

Looks like it's bumped to Saturday? And sorry, I have trouble keeping up -- what is the payload for this launch? Thanks.

https://www.cnn.com/2023/11/16/world/starship-spacex-launch-scn/index.html

The megarocket — the most powerful launch vehicle ever built — was expected to lift off on Friday, but SpaceX CEO Elon Musk said in a social media post Thursday that the company would hold off until Saturday to allow for time to replace a small rocket part.

The company is targeting a 20-minute launch window that opens Saturday at 7 a.m. CT (8 a.m. ET), according to the SpaceX website.

Musk shared that the reason for the delay was the need to replace an actuator — or a mechanical component that allows movement — on one of the rocket’s grid fins. Grid fins are metal, mesh squares that line the top of Starship’s Super Heavy rocket booster, and they’re used to orient the booster as it heads in for a landing after flight.

Riding on Starship’s eventual success is the company’s hopes for human exploration of the moon and Mars.

 

[mfb]

Saturday, same time.
No payload, it's just a test flight.

On future flights, Ship 26 (no heat shield) might test propellant transfer inside the ship, Ship 28 or 29 might test deployment of Starlink satellites.

 

[.Scott]

On the good side, the delay was caused by the actuator for one of the grid fins. So we can expect that SpaceX will be attempting to crash the booster into some very specific random spot in the Gulf.

 

[.Scott]

It looks like they got the big pieces of the rocket back together at about 9:30 this morning CST. But they have been playing with the upper stage every since then.
Still scheduled for 7am CST Saturday (tomorrow).

 

[mfb]

The booster is expected to make a soft landing in the Gulf of Mexico, mimicking the return profile for reuse but staying away from the coast.

T-5:50:00 until the launch window opens.

For the April flight, they started cooling down propellant lines 3 hours before the launch, this was visible as some venting on the launch mount. The "go" for propellant load is expected to happen around 2 hours before the launch. Not sure if we'll see that, but we should see the actual propellant loading from T-1:37 on.

SpaceX timeline
More detailed unofficial timeline

Livestreams:
NASA Spaceflight (active)
Everyday Astronaut (only showing the rocket now)
SpaceX (might start half an hour before takeoff or so)

 

[mfb]

T-1:37 for the launch window. Propellant loading has started, will take ~1:30 and can end a few minutes before takeoff. SpaceX's webcast will start 35 minutes before takeoff, which should be an hour from now. The launch window is only 20 minutes long, SpaceX seems to target the start of the window.

 

[mfb]

2 minutes

Edit: Hold at -40 seconds
Can hold there for up to 15 minutes.
Edit: back to countdown

So much condensation:

 

[mfb]

Liftoff with all engines!

Successful hot staging.

Booster exploded during boostback burn afterwards. Ship is still flying.

Telemetry cut off towards the end of the ship burn. Looks like it exploded shortly before reaching orbital velocity.

No major damage to the launch pad, although one tank looks like it has a dent now (edit: this dent could still have been from the first flight, haven't seen before/after pictures). No engine failures. Successful hot staging and a long second-stage flight. A huge step up from the first test. I expect the third test to reach orbit.

 

[nsaspook]

 

[nsaspook]

 

[mfb]

Starship has beaten the record for the heaviest object in space by a factor ~2 or so.
~1000-1100 tonnes vs. ~500 tonnes for Saturn V and 450 tonnes for the ISS.

Hot staging looked amazing.

Tracking shots:

 

[Astronuc]

SpaceX’s Starship reaches space for first time but explodes moments later
https://www.theguardian.com/science...h-starship-rocket-after-second-launch-attempt

But about two and a half minutes into the flight, the two stages of the spacecraft broke apart. SpaceX shortly announced that it could not find a signal from the second stage, which it declared “lost”.

The company believes the rocket’s self-destruction mechanism was set off after it lost the signal.

SpaceX’s second flight is an improvement compared to its first test launch in April, when both stages ultimately exploded four minutes into its flight. The spacecraft’s first stage, nicknamed “Super Heavy” for its 33 engines, had failed, causing both stages to explode.

Starship's first liftoff toward space created the equivalent of a volcanic eruption in the launchpad, physicist finds​

https://www.msn.com/en-us/news/tech...-in-the-launchpad-physicist-finds/ar-AA1k3Qmc

At least they didn't wreck the launch pad during the 2nd attempt.

 

[mfb]

The Guardian article is absurd.

Elon Musk’s next-generation craft reaches space but then explodes, similar to first flight in April

The April flight didn't reach space, or got anywhere close to what the second flight achieved.

But about two and a half minutes into the flight, the two stages of the spacecraft broke apart.

That's called stage separation and it worked exactly as planned. No "but" about it. The second stage ignited and started its flight.

SpaceX shortly announced that it could not find a signal from the second stage, which it declared “lost”.

That happened 5 minutes later, after the upper stage accelerated from 1.5 km/s to 6.5 km/s, just a bit short of the ~7.3 km/s target.

If you read the article you'd think Starship exploded just after stage separation, which is obviously not what happened.

 

[mfb]

Launch pad after the April launch (left) and after this launch (right).



View from the ground

Nothing official yet, and the accident investigation will take some time, but there are already useful speculations what might have happened:
* Propellant sloshing might have starved booster engines during the flip maneuver. Taking in gas instead of liquid can easily destroy the engines.
* Something caused the ship to lose liquid oxygen towards the end of its burn. If the ship decided that it can't reach the Pacific safely then it had to trigger its flight termination system to make the debris reenter over the Atlantic (as it did).

 

[.Scott]

Starship has beaten the record for the heaviest object in space by a factor ~2 or so.
~1000-1100 tonnes vs. ~500 tonnes for Saturn V and 450 tonnes for the ISS.

As if it isn't hard enough to build a skyscraper, they have made one that can launch itself into space.

Perhaps the most important point is that this launch appears to be very close to what the FAA and FWS expected in terms of safety and conservation. As best we know, everything at ground level happened as predicted - and as accepted by the FWS. And the crafts continued within their planned corridors until interrupted by the Flight Termination Systems - both of accomplished their tasks emphatically.

The FWS application was for a launch cadence of 12 per month.

As best we can tell at this point is that SpaceX will be cleared for another test as soon as they are ready.

Also, as best as I can tell, this re-review over the past eight months has pretty much addressed the main points of the civil actions that were taken by conservation groups last year against the FAA for certifying Starship flights. Of course, this isn't to say that those groups can't start afresh.

 

[nsaspook]

 

[pinball1970]

Just a short article over the weekend.

https://phys.org/news/2023-11-spacex-poised-mega-starship-rocket.html

"Its Super Heavy booster produces 16.7 million pounds (74.3 Meganewtons) of thrust, almost double that of the world's second most powerful rocket.."

Wow!

 

[Rive]

A huge step up from the first test. I expect the third test to reach orbit.

Quite decent progress.
Is it known whether the fuel was filled 'full', or just up to the amount required for the test?

 

[.Scott]

We got this tweet (or X) from Elon last night:

Starship Flight 3 hardware should be ready to fly in 3 to 4 weeks. There are three ships in final production in the high bay (as can be seen from the highway).

So converting from Elon time to approximate conventional time, the FAA has about 7 weeks to get their investigation wrapped up and get the paperwork out before Elon will go back to Congress and ask to double the FAA investigative staff again.

 

[mfb]

Quite decent progress.
Is it known whether the fuel was filled 'full', or just up to the amount required for the test?

Fuel is cheap, filling it up completely gives you larger margins. If Starship becomes as rapidly reusable as planned then maybe fuel cost becomes an important factor and we might see launches with less fuel.

Before the next flight, SpaceX needs to identify what went wrong with the two stages, find a way to fix that, start implementing that in the hardware and/or software for the third flight, write a report and send that to the FAA. Then the FAA needs to approve it. It's true that they have a booster and a ship almost ready to fly, but repeating the second flight with no changes makes no sense. There is some work to do, and at the moment the critical path is with SpaceX.

Predictions:
* SpaceX will submit its report at some point in January. FAA will approve it in February to March, with a flight quickly after approval.
* No major hardware changes as result of the booster explosion, updated software to improve the flip maneuver.
* Some oxygen leak on the ship, SpaceX will reinforce the system (might also affect the booster) or determine that ship 28 already has upgrades that eliminate this problem.
* Booster 10 will survive the flip and boostback burn and start a landing burn over the ocean (which might or might not be successful).
* Ship 28 will reach a transatmospheric orbit or a low Earth orbit depending on what is planned, but fail in the atmosphere on reentry.
* We will get news articles how Starship "explodes for the third time", despite all other rockets doing the same with their upper stages after reaching orbit.

 

[berkeman]

Fuel is cheap, filling it up completely gives you larger margins. If Starship becomes as rapidly reusable as planned then maybe fuel cost becomes an important factor and we might see launches with less fuel.

Plus it seems like they would want to launch with full weight to get that data.

Related question -- were they carrying a dummy payload to simulate the weight of anticipated payloads?

 

[mfb]

Haven't heard anything about a dummy payload. It doesn't make a big difference - you can just end the flight with some extra fuel in the rocket. Typically payloads are much heavier than the upper stage, so dummy masses are important, but Starship is about as massive as its payload capacity. Take into account that the prototypes are probably heavier than the final product and you have a lot of "dummy mass" already in the vehicle.

 

[berkeman]

Take into account that the prototypes are probably heavier than the final product and you have a lot of "dummy mass" already in the vehicle.

Ah, interesting. Good point.

 

[Rive]

Fuel is cheap, filling it up completely gives you larger margins.

That's nice, but if you suggest that for this occasion they well filled to the brim then those fuel indicator bars of the 'live' feed ran awful fast for a no-load launch just to the edge of space.

I hoped that if the amount of fuel they got is known then we might get some data about the capacity.

 

[nsaspook]

I've been waiting for this video series.

[4K Slow-Mo] Starship IFT-2 Supercut with clean audio and tracking!​

 

[.Scott]

Before the next flight, SpaceX needs to identify what went wrong with the two stages, find a way to fix that, start implementing that in the hardware and/or software for the third flight, write a report and send that to the FAA. Then the FAA needs to approve it. It's true that they have a booster and a ship almost ready to fly, but repeating the second flight with no changes makes no sense. There is some work to do, and at the moment the critical path is with SpaceX.

Though Elon is probably willing to publish a estimated completion time (as 3 to 4 weeks) with knowing what needed to be done, I would still guess that the core problems have already been identified.
The FAA has already announced that they are investigating, and since the issues are likely known, the paperwork is likely already in progress.
There are probably a handful of issues related the causes of this 'accident" and a handful of test and installation procedures that will be required for FAA review. But by now the FAA may already be saturated in reviewing the causes and they may remain saturated throughout the flight review process. So the FAA may already own the critical path.

 

[.Scott]

No, this isn't scifi!

It's hot stage separation.
(photo compliments of SpaceX via X)

 

[mfb]

That's nice, but if you suggest that for this occasion they well filled to the brim then those fuel indicator bars of the 'live' feed ran awful fast for a no-load launch just to the edge of space.

I hoped that if the amount of fuel they got is known then we might get some data about the capacity.

I don't know what you expect. The fuel consumption rate does not depend on the payload mass. It's determined by the engines. The expected payload is ~10% of the fully fueled Starship, launching with no payload means something like 10% of the fuel will be left when it reaches its target velocity. It was ~95% through the second-stage flight, so it had consumed ~95% of the fuel it needed.

----

Slow motion tracking shot. Look at these Mach diamonds!

 

[Rive]

I don't know what you expect.

Well, something like this.
I had that feeling that either those fuel bars were not about the maximal capacity but about the actual fill (required for the task planned) or the flight performance just fell short, especially for no load.

No biggie (it's the same feeling when they smashed the first Falcon recovery attempts - it could be already seen/felt that nothing there what cannot be solved) but also not great (yet).
A nice flight, a stable progress: no less and no more.

 

[pinball1970]

No, this isn't scifi!
View attachment 335908
It's hot stage separation.
(photo compliments of SpaceX via X)

Incredible image, worthy of using as an avatar!

 

[.Scott]

In an X message, Elon described a lighter bigger Starship version 2. There will only be 6 version 1's, the two launched plus four that are parked near the Starship bays in Texas.

 

[mfb]

The third flight will include a propellant transfer demo (within the spacecraft). Confirmed here by NASA.

It's a funny contrast to Blue Origin on the same slide: "Mockup delivered".

 

[mfb]

Static fire of booster 10 with all 33 engines:



The ship has done a static fire test as well. Looks like the hardware will be ready soon and then we'll wait for regulatory approval again.

 

[mfb]

Company update from Musk

The second flight is discussed at ~49:20: It might have reached orbit if it had carried a payload. It didn't, so it vented its excess oxygen - and that started a fire that destroyed the ship.

The third flight is expected to reach orbit, it will do a short engine burn there to demonstrate controlled deorbiting. Rumors say February, if they have completed the accident investigation and it was something as avoidable as venting oxygen I can see that happening.

 

[mfb]

Booster assembly line

Edit: The three assembled boosters are 10 (left, will make the next flight), 12 (center), 11 (right), and booster 13 is in two pieces in the far left and far right.