SpaceX Starship - IFT-3 - Starbase TX - Launch Thread and Post Launch Discussion

Launch Date: March 14
Launch Window: 7:00 am CDT (9:00 am EST, 13:00 UTC)
Launch site: LC-1 - Starbase, Boca Chica Beach, Texas
Core Booster Recovery: Expended in Gulf with a landing burn
Starship Recovery: A controlled reentry through the atmosphere to a terminal velocity splashdown in the Indian Ocean
Booster: Super Heavy Booster 10
Starship: Starship 28
Mass: No mass simulator mentioned
Orbit: LEO-ish
Yearly Launch Number: 26

A SpaceX Super Heavy and Starship launch vehicle will launch on its third not quite orbital integrated flight test designated IFT-3. The mission will attempt to place Starship into a nearly orbital trajectory that will attempt a controlled reentry through the atmosphere to a terminal velocity splashdown in the Indian Ocean . The Super Heavy booster will attempt a landing burn in the the Gulf of Mexico where it will likely be destroyed. This is a further test of Stage 0, the booster, full power ascent, Max-Q, stage separation using the new hot staging, a booster stage test of a hard turn and boostback, full burn boost of Starship to space and sub LEO, Starship will do one partial orbit, simulate a de-orbit burn, test tiles and heating from atmospheric reentry, until it has a splashdown in the Indian Ocean.

It has also been determined that for this test flight there will be a fuel transfer test done on Starship for NASA's Tipping Part contract. The Starship will also test its payload bay door in zero-G for a test of future Starlink 2.0 deployments.

 

[Buckminster]

https://twitter.com/x/status/1768339594049687831

 

[HVM]

If so, it clearly... needed... more... cowbell... never can get enough cowbell!

I have no idea what y'all are talking about,

 

[Buckminster]

https://twitter.com/x/status/1768550892502909255

Not surviving reentry is fundamental. Any theories?

 

[HVM]

It was a test flight so not "fundamental". Ship has lost it's attitude control and so had no way to survive reentry.

 

[ecarfan]

Not surviving reentry is fundamental. Any theories?

It was discussed upthread that perhaps the RCS failed in some way resulting in loss of attitude control. Well before reentry the ship did not appear to have effective attitude control. Then at reentry the ship was unable to keep the TPMS facing the “hot” side. Also, by then a number of tiles appeared to have been dislodged; even if the ship had oriented properly loss of even a single tile could theoretically be fatal.

To the general public this test flight could appear to be a failure, but it’s clear to me that with each flight SpaceX is making significant progress and achieving additional milestones. I am confident that trend will continue and believe it likely that by the end of this year we will see a booster and ship make a successful soft water landing. That assumes that the FAA issues launch license process speeds up because with each flight there are fewer issues that need investigating.

 

[JohnnyEnglish]

I am hoping that SpaceX had a camera in the starboard flap too as that side seems to have been more exposed to unexpected aerodynamic and heating loads. Would love to see that footage.

Last century I was peripherally involved in the analysis work on the Giotto spacecraft following its flypast of Halley's comet to determine how much damage it had sustained passing through the comet's tail and if it was in a fit state to perform any further flypasts (turns out it was). I am sure the SpaceX team are enjoying the huge challenge of sorting and analysing all the data they received and determining what it means and how to leverage it ahead of IFT-4.

Given the absolutely fantastic fantastic views we saw this time I am really looking forward to a controlled attitude for Starship during IFT-4. I was very impressed with the resilience of Starship given the exposure of unprotected areas. The protected areas that we could see did not sustain visible damage so I am hopeful they can cope with the design conditions.

 

[scaesare]

I am hoping that SpaceX had a camera in the starboard flap too as that side seems to have been more exposed to unexpected aerodynamic and heating loads. Would love to see that footage.

Last century I was peripherally involved in the analysis work on the Giotto spacecraft following its flypast of Halley's comet to determine how much damage it had sustained passing through the comet's tail and if it was in a fit state to perform any further flypasts (turns out it was). I am sure the SpaceX team are enjoying the huge challenge of sorting and analysing all the data they received and determining what it means and how to leverage it ahead of IFT-4.

Given the absolutely fantastic fantastic views we saw this time I am really looking forward to a controlled attitude for Starship during IFT-4. I was very impressed with the resilience of Starship given the exposure of unprotected areas. The protected areas that we could see did not sustain visible damage so I am hopeful they can cope with the design conditions.

Indeed... clearly stainless steel isn't going to hold up to that intense hot plasma... but it certainly seemed to hold up well given what it was exposed to... looking like a good choice for materials....

 

[scaesare]

At 1:18:45 in the SpaceX video, what looks like little bits of ice start floating past the camera. Right at 1:18:53, the camera jumps, and then the dark debris floats by. I wonder if there was tile debris in the flap mechanism from earlier in the flight, and the motors eventually overpowered the debris, crushing both it and whatever it was jammed against.

It may be nothing, and the sudden camera movement was just a normal, sudden flap movement, but it looks like a whipsaw motion that would match up with a jammed, then freed, then stabilized motorized joint.

Yeah... may be... I took that to be rapid flap motion with control system trying to adjust to it tumbling.... but it also does seem to be a bit more abrupt thatn the rear flap the cam is aiming at...

Upon re-watch, I also think that much of what looked like black material may simply have been ice in the shadows of the ship as it rotated... at 1:19:17 a large dark chunk enters on the bottom of the frame, and as it passes the belly of the ship it curves towards the left of the frame and at 1:19:19 it enters the sunlight and it immediately becomes clear it's a white piece of material... presumably ice and not a tile...

A bunch of the other smaller pieces do similar.

 

[JB47394]

It was discussed upthread that perhaps the RCS failed in some way resulting in loss of attitude control. Well before reentry the ship did not appear to have effective attitude control. Then at reentry the ship was unable to keep the TPMS facing the “hot” side.

I was surprised that the flaps were unable to stabilize the vehicle. I have had to reset my expectations about reentry to understand that the atmosphere is extremely rarified at 100 km, making it useless for aerodynamic controls, but it is still coming at you at 26,000 km/h, which will produce a lot of heat.

Apparently the highest altitude that aerodynamic controls can be used is about 80 km. The shuttle performed its S-turn maneuvers starting at 48 km.

So between about 100 km and 80 km, you're obliged to just endure the heating.

Also, by then a number of tiles appeared to have been dislodged; even if the ship had oriented properly loss of even a single tile could theoretically be fatal.

STS-27 lost a tile and survived. It exposed a tin-plated aluminum access door. The tin plating was melted, and the aluminum was softened. I think that it would take a large area of tile loss on a Starship to produce a failure. It has the tiles, then the fabric layer, then the stainless steel of the hull. I guess a possible exception would be something like an edge of a flap, which probably has higher heating than the cylindrical body. That's just speculation.

Indeed... clearly stainless steel isn't going to hold up to that intense hot plasma... but it certainly seemed to hold up well given what it was exposed to... looking like a good choice for materials....

Stainless steel is amazing stuff. When a spacecraft reenters and something survives, it'll be the stainless steel bits. Perhaps not intact, but stainless is tough stuff.

I wouldn't be surprised that the loss of the vehicle was related to parts that weren't stainless steel at all. Surely the most vulnerable parts would be on the stainless steel side because it is least affected by heating. Electronics, and so forth. So even if the ship could have remained intact by the use of the flaps, killing the electronics would mean a total loss of control.

 

[scaesare]

Methane is a carbon fuel, so if the engines are running fuel rich at all, there would be some crud being formed. One possible source of an enriched propellant could be methane film cooling. If SpaceX is at all aggressive with that cooling, they could end up with a bit of excess methane going into the exhaust and producing partially oxidized products such as methanol, formic acid, formaldehyde and higher hydrocarbons. Gunk.

Yeah... we also saw the exhaust flame appear much more orange in some of the "high chamber pressure" Raptor tests, whereas previously they had been all purple... that color change likely due to increased film cooling.

The Raptors on the booster appear to be much more purple, so I suspect they aren't yet pushing chamber pressures as high as they've tested, but it still appears not quite as pure-purple as earlier revisions... lending credence to the running rich for film-cooling, and thus producing some combustion byproducts...

 

[scaesare]

I was surprised that the flaps were unable to stabilize the vehicle. I have had to reset my expectations about reentry to understand that the atmosphere is extremely rarified at 100 km, making it useless for aerodynamic controls, but it is still coming at you at 26,000 km/h, which will produce a lot of heat.

Apparently the highest altitude that aerodynamic controls can be used is about 80 km. The shuttle performed its S-turn maneuvers starting at 48 km.

So between about 100 km and 80 km, you're obliged to just endure the heating.


STS-27 lost a tile and survived. It exposed a tin-plated aluminum access door. The tin plating was melted, and the aluminum was softened. I think that it would take a large area of tile loss on a Starship to produce a failure. It has the tiles, then the fabric layer, then the stainless steel of the hull. I guess a possible exception would be something like an edge of a flap, which probably has higher heating than the cylindrical body. That's just speculation.


Stainless steel is amazing stuff. When a spacecraft reenters and something survives, it'll be the stainless steel bits. Perhaps not intact, but stainless is tough stuff.

Yeah, I suspect that, upon breakup especially, the larger surface area-to-weight ratio slowing them and the durability will allow quite a bit to survive.

I wouldn't be surprised that the loss of the vehicle was related to parts that weren't stainless steel at all. Surely the most vulnerable parts would be on the stainless steel side because it is least affected by heating. Electronics, and so forth. So even if the ship could have remained intact by the use of the flaps, killing the electronics would mean a total loss of control.

Agreed, it would get to be an oven for that stuff pretty quickly.

I was thinking of the Columbia disaster, where the puncture allowed the hot plasma to get into the internals and soften and/or melt aluminum structure...

Obviously, SS is going to be more resilient than that... but prolonged exposure of even SS to ~2700 degree (F) temps is going to soften it to the point of losings structural integrity (although we don't know the exact specs for the alloy SX developed, I assume it's in the ballpark of the SS family).

Combined with the lack of control of the ship, I expect there's some severe unintended stress that structure is having to endure, all the while softening more by the second.

Which leads to questions:

1- Is the primary load of the ship carried by the SS skin + stringers? (It seems so from the ring construction). I also assume the stringers are SS.

2- If the answer to #1 is "No", what are the internal structures made of? Also SS or aluminum?

 

[mongo]

1- Is the primary load of the ship carried by the SS skin + stringers? (It seems so from the ring construction). I also assume the stringers are SS.

That's the only structure, and yep, stringers are stainless also.

 

[JB47394]

That's the only structure, and yep, stringers are stainless also.

On top of that, the pressure in the tanks is an important part of the structural rigidity. I mentioned electronics earlier, but there are other vulnerable components. Could a vent have been compromised by heat? That could cause a loss of pressurization, making the structure more prone to buckling.

 

[JohnnyEnglish]

Can't be 100% sure but isn't the ship skin made of 3mm SS?

SS is a reasonable conductor so we can assume that if the outside skin temperature is 1300K then the inside skin temperature will also be 1300K. As far as I am aware the LOX and CH4 tanks are single skin so both of these liquids will be seeing that 1300K. I would expect some pretty significant heating of the remaining liquids and/or vapour.

 

[JB47394]

Can't be 100% sure but isn't the ship skin made of 3mm SS?

Yeah, it's just below 4 mm. I think the exact number is 3.97 mm. They wanted to go to 3 mm at one point, but I guess that didn't work out. Like you, I'm not 100% sure, but that was the way things were about a year ago.

I would expect some pretty significant heating of the remaining liquids and/or vapour.

It would certainly make sense. I'm sure the vents would try to keep up, but if too much was going gaseous, perhaps they had a hull rupture.

The ship was in free fall and not being accelerated anywhere, so the propellants would be floating around in the tanks. Perhaps just a touch of deceleration arrived towards the end, a blob of propellant contacted that hot wall and... boom.

 

[JB47394]

It looks like they completed the LOX transfer.

NASA Artemis Mission Progresses with SpaceX Starship Test Flight - NASA

As part of NASA’s Artemis campaign to return humans to the Moon for the benefit of all, the agency is working with SpaceX to develop the company’s Starship

www.nasa.gov

One objective closely tied to future Artemis operations is the transfer of thousands of pounds of cryogenic propellant between internal tanks during the spacecraft’s coast phase as part of NASA’s Space Technology Missions Directorate 2020 Tipping Point awards. The propellant transfer demonstration operations were completed, and the NASA-SpaceX team is currently reviewing the flight data that was received. This Tipping Point technology demonstration is one of more than 20 development activities NASA is undertaking to solve the challenges of using cryogenic fluids during future missions.

 

[ecarfan]

We discussed the apparent rolling of the ship during coast phase. Rewatching the test flight video, I noticed that during coast when there was no video signal, the ship graphic showed a slow roll around the long axis, with no pitch changes, that seemed to match what you could see happening when there was a video signal. For example, go to T+19:36, watch the graphic, and then shortly thereafter the video comes back and the ship is rolling at the same rate as the graphic, in my opinion. I think that roll was likely intentional and controlled. Then after about T+23:10 the ship graphic at the bottom started to show pitch changes.

 

[ecarfan]

Regarding the cargo door test, I found it very hard to tell from the one camera angle how far the door was opened. There was a brief view at around T+14:23 showing the door in the close position (I think) and then later a view from a different camera with the door at least partially open. Don’t know why they switched views in the public feed. At T+28:34 I think the callout said “Pez checkout complete, door is closing” but I don’t see any movement. At T+30:20 the door visibly jerks and sort of pops away from the wall of the ship but does not rise up. Does seem like a test failure. And yet at T+38:30 Kate says that test objective “has been met.” So she obviously knows better than I!

 

[ecarfan]

During prop loading there were clouds of condensate coming off the ground extending out into the wetlands area but the wind wasn’t blowing it that way, in fact it was blowing the opposite direction. I don’t understand that.

 

[JB47394]

I think that roll was likely intentional and controlled.

I seem to recall SpaceX saying that the engine relight wasn't performed because of the roll.

Don’t know why they switched views in the public feed.

Perhaps it was decided that a sideways view was going to confuse people over what they were looking at.

I thought the "down" view was inside the oxygen tank because of all that shimmering. It was apparently dust floating around inside the cargo area, being lit by the sliver of light coming in through the door.

I don’t understand that.

Cold air sinks because it is dense. Cryogenic gases may be so cold and dense that they sink so hard that they'll actually flow downhill. The dunes and such may also prevent the air from catching the gases and moving them.