totm nov 2023 SpaceX Discussion Thread

[Elthy]

Damn, Starship did just what every other rocket did for decades: Splashdown of the first stage, destructive reentry for the second, both at predetermined spots...

[JoeSchmuckatelli]

Just now, Elthy said:

Damn, Starship did just what every other rocket did for decades: Splashdown of the first stage, destructive reentry for the second, both at predetermined spots...

Welcome to the club?

[mikegarrison]

Here's how it works, to the best of my knowledge. You write a plan of what you are going to test. The plan gets approved. You conduct the test.

If things go according to the plan, that's fine. If they don't, that's what needs to be investigated and resolved.

It's up to SpaceX what they write in their plan. If it had just said "Splashdown of the first stage, destructive reentry for the second, both at predetermined spots..." then that would have been good enough. Obviously the plan must not have said that, though.

[CatastrophicFailure]

10 hours ago, Exoscientist said:

 Is it confirmed the hot gas RCS  worked on the booster but not on the Starship? If so, then the propellant transfer test may have caused a fuel leak preventing the RCS from operating.

 

   Bob Clark

 

10 hours ago, RCgothic said:

No, the causes of the losses of control on both booster and ship are unconfirmed.

Unconfirmed, yes, tho something like this does appear to be the case.  The booster was under complete control via thrusters until the grid fins "kicked in." If you watch it sped up the control actually looks quite crisp, for a much larger and more massive vehicle vs an empty Starship. It looks to me like it wasn't a case of the SS thrusters not working well enough towards the end, they didn't seem to be working at all. Possibly with a leak of some sort adding in that uncontrolled roll. It's far too early to say if the boiloff-based thrusters work or not at this point. Tho I bet SpaceX themselves already know the solution.

8 hours ago, CBase said:

I am curious how SpaceX will change the ship for IFT-4.

If I had this playing Kerbal, I would probably integrate an overkill of control thrusters and accept temporarily a reduced payload. Any payload to destination is better than none. When piloting is mastered, I would reduce thrust limits to see what I actually need and then refine build to match actual demand for control.

If I had this playing Kerbal, I'd rage quit for a few hours, come back, build an even BIGGER rocket, BRAKE IT TO A COMPLETE STOP 100km above KSC, bring it down under power the entire descent and land it directly on top of the VAB just to stick it to the game, laughing maniacally the whole time.

 

 

...Then rage quit again when it ever-so-slowly tips over and explodes literally everything. 

[CatastrophicFailure]

Also, I'm not saying it was this, but neither can this be ruled out at this point either...

Spoiler

 

[Pthigrivi]

27 minutes ago, CatastrophicFailure said:

Unconfirmed, yes, tho something like this does appear to be the case.  The booster was under complete control via thrusters until the grid fins "kicked in." If you watch it sped up the control actually looks quite crisp, for a much larger and more massive vehicle vs an empty Starship. It looks to me like it wasn't a case of the SS thrusters not working well enough towards the end, they didn't seem to be working at all. Possibly with a leak of some sort adding in that uncontrolled roll. It's far too early to say if the boiloff-based thrusters work or not at this point. Tho I bet SpaceX themselves already know the solution.

Agreed. Again--unconfirmed, but I see 3 likely reasons for booster RUD: A) the engine relight should have worked but was delayed/asymmetric and threw off the suicide burn, or B1) gridfins were miscalibrated / B2) the grid fins were deliberately testing control authority range. Granted this is a MUCH larger vehicle than falcon 9 and fuel mass slosh, descent speed etc. are very different but aerodynamic control is something SX has a lot of experience with. I'll be curious to hear more info on this.

Starship is different. I've heard some vehicles deliberately roll in orbit to manage heat... but...? given the sound of crowd reaction in the room, the plan for a fuel transfer and relight test I think this roll was not in-program. You can see the vehicle is basically continuously venting through most of the suborbital journey and if those ports are exactly oppositional to keep tank pressure constant that shouldn't be a problem. If there is a bias at all--even slight--it could induce rotation and tumbling over time. Once they reentred with the atmosphere so thin it didn't look like the fins could reasert roll stability, but worse Starship pitched aft-down. Someone could correct me but I thought I heard the fuel transfer was supposed to move propellant to the header tank at the nose of the vehicle, which would have helped keep the nose down and forward as air pressure built up rather than tilting engines-down.

Edited March 17 by Pthigrivi

[magnemoe]

3 hours ago, mikegarrison said:

Here's how it works, to the best of my knowledge. You write a plan of what you are going to test. The plan gets approved. You conduct the test.

If things go according to the plan, that's fine. If they don't, that's what needs to be investigated and resolved.

It's up to SpaceX what they write in their plan. If it had just said "Splashdown of the first stage, destructive reentry for the second, both at predetermined spots..." then that would have been good enough. Obviously the plan must not have said that, though.

Splashdown is splashdown even at low speed. They could set virtual landing target at 500 meters so you hover there and then kill trust and fall. 
The Falcon 9 first stage landing test was never an issue as it was inside the hazard zone and it reduced risk as it would be one craft under some control rather than something breaking up in the atmosphere creating an field of fast moving junk. 
 

[Flying dutchman]

I can't seem to find any tracking shots of the booster after separation. Everyday astronaut uploaded a compilation, but every tracking shot ends just after hotstaging. Has anyone got footage of the booster?

[darthgently]

34 minutes ago, Flying dutchman said:

I can't seem to find any tracking shots of the booster after separation. Everyday astronaut uploaded a compilation, but every tracking shot ends just after hotstaging. Has anyone got footage of the booster?

It was very cloudy and it came down fairly far Boca Chica.  I think the boost back was mostly just cancelling  most horizontal velocity, not a RTLS burn.  Maybe the military or SpaceX had some drone or other out there getting footage, time may tell, or may not.  I'm guessing, of course, but if I were a bigwig in the military I'd definitely use the opportunity to test the capabilities of some surveillance asset in cooperation with SpaceX and presumably the FAA

Edited March 17 by darthgently

[tater]

I didn't see the WB-57 on flightradar24.

[darthgently]

35 minutes ago, tater said:

I didn't see the WB-57 on flightradar24.

That's disappointing.  But NASA is budget crunched and that craft doesn't fly for free.  The Pentagon however has displayed focused interest in SH and seems to be quite nonchalant in their budgeting and accounting.  Anyway, it would be nice if at some point some great footage existed and was declassified or whatever. 

On a related note, it was curious that the NASA video of IFT-2 on their site had the hot staging edited out.  ITAR concerns seem a stretch, but that leaves the question as to why edit it out?  I got nothing

 

Edited March 18 by darthgently

[tater]

10 minutes ago, darthgently said:

That's disappointing.  But NASA is budget crunched and that craft doesn't fly for free.  The Pentagon however has displayed focused interest in SH and seems to be quite nonchalant in their budgeting and accounting.  Anyway, it would be nice if at some point some great footage existed and was declassified or whatever. 

On a related note, it was curious that the NASA video of IFT-2 on their site had the hot staging edited out.  ITAR concerns seem a stretch, but that leaves the question as to why edit it out?  I got nothing

I think it was on the schedule—maybe they had an operational problem, or maybe not on radar.

[SunlitZelkova]

16 hours ago, Elthy said:

Damn, Starship did just what every other rocket did for decades: Splashdown of the first stage, destructive reentry for the second, both at predetermined spots...

Do we know if it was in the predetermined spots though?

What is the possibility there wasn't enough control (and clearly was not enough control of Starship during reentry) that it went outside the designated landing/impact zones?

[darthgently]

2 hours ago, SunlitZelkova said:

Do we know if it was in the predetermined spots though?

What is the possibility there wasn't enough control (and clearly was not enough control of Starship during reentry) that it went outside the designated landing/impact zones?

If it broke up at signal loss wouldn't debris fall earlier than nominal?  Still, it seems that area would have been in the exclusion zone.  Maybe getting too near the edge of an exclusion zone triggers a "mishap", idk

Edited March 18 by darthgently

[Cuky]

My feeling is that mishap isn't because of braking up during re-entry but rather because of problems they had with controling both the booater and the ship. I may be wtong but I understood that goal of this flight was to get to orbital speed, test control of booater when returning, show that they cen transfer fuel internaly on the ship, test the control of a ship a d re-enter the atmosphere with hipefully not breaking up. Both booster and shio had problems with control and mishap investigation will probably look into reasons behind that.

[magnemoe]

3 hours ago, Cuky said:

My feeling is that mishap isn't because of braking up during re-entry but rather because of problems they had with controling both the booater and the ship. I may be wtong but I understood that goal of this flight was to get to orbital speed, test control of booater when returning, show that they cen transfer fuel internaly on the ship, test the control of a ship a d re-enter the atmosphere with hipefully not breaking up. Both booster and shio had problems with control and mishap investigation will probably look into reasons behind that.

Yes, most assumed it would brake up, surviving reentry was an low chance. The lack of control was the problem. 

[Minmus Taster]

Uhm... how exactly?

https://www.space.com/spacex-starship-go-interstellar-elon-musk-says

[GuessingEveryDay]

22 minutes ago, Minmus Taster said:

Uhm... how exactly?

https://www.space.com/spacex-starship-go-interstellar-elon-musk-says

This, but every little wood slab is actually a Starship.

[darthgently]

11 minutes ago, GuessingEveryDay said:

This, but every little wood slab is actually a Starship.

Thanks for clarifying!

[CBase]

8 hours ago, darthgently said:

Maybe getting too near the edge of an exclusion zone triggers a "mishap", idk

We can actually look up what triggers a mishap investigation at https://www.faa.gov/space/compliance_enforcement_mishap (with emphasis by me):

Quote

The new FAA regulations describe nine events (see below) that would constitute a mishap (14 CFR 401.7). The occurrence of any of these events, singly or in any combination, during the scope of FAA-authorized commercial space activities constitutes a mishap and must be reported to the FAA (14 CFR 450.173(c)).

• Serious injury or fatality
• Malfunction of a safety-critical system
• Failure of a safety organization, safety operations or safety procedures
• High risk of causing a serious or fatal injury to any space flight participant, crew, government astronaut, or member of the public
• Substantial damage to property not associated with the activity
• Unplanned substantial damage to property associated with the activity
• Unplanned permanent loss of the vehicle
• Impact of hazardous debris outside of defined areas
• Failure to complete a launch or reentry as planned

Since the official flight plan probably did not contain a a disassembly at the actual altitude, formally both conditions match for either stage.
At least somewhere I read that booster did not splash down, but expierenced a RUD at ~400m altitude (however I can not find the source right now). So

 

Edited March 18 by CBase

[darthgently]

35 minutes ago, Minmus Taster said:

Uhm... how exactly?

https://www.space.com/spacex-starship-go-interstellar-elon-musk-says

He is either thinking generation ships or assuming advanced handwaving is far more realistic in the far future.

I can see a path where space habitats become so advanced and self-sufficient that it wouldn't be unreasonable for something with the population of a major city to make its way to another star system over many generations.

I'm in the "show me" camp wrt FTL travel.

 

[Ultimate Steve]

I'm reading "A future Starship" as, like, a Starship, the only similarity to Starship-Superheavy being the name. To me this doesn't read like "We are going to send Starship to colonize Alpha Centauri", instead reading like "If everything goes well, eventually we might be able to go interstellar with a different design ."

Which is still more than a little crazy, but I kind of admire that they don't plan on stopping at Starship.

I've said it before and I'll say it again. They could have stopped at Falcon 9 and made bank and be remembered as heroes. Instead they are working on a Mars colonization rocket. That sounded almost as crazy back in 2016 when they announced it.

Granted, they aren't gonna get there on chemical fuels, so unless Musk has a stealth fusion startup we don't know about yet...

[darthgently]

Being into sailing, I do stubbornly hold onto the possibility that just as a sailboat can make use of the differential flux between wind and water via a sail and a keel that maybe we'll be able to go interstellar using stellar and galactic wind for our sails and something yet to be discovered to jam our "keel" into. 

Of course one can sail downwind without a keel on water, but if you want more directional control you need another medium to stick the other sail, the keel, into.  Then you can reach perpendicular to the wind and even tack upwind within limits

Maybe as we figure out dark matter and dark energy we will find something to leverage against using solar sails 

 

Edited March 18 by darthgently

[Spaceception]

5 minutes ago, Ultimate Steve said:

I'm reading "A future Starship" as, like, a Starship, the only similarity to Starship-Superheavy being the name. To me this doesn't read like "We are going to send Starship to colonize Alpha Centauri", instead reading like "If everything goes well, eventually we might be able to go interstellar with a different design ."

Which is still more than a little crazy, but I kind of admire that they don't plan on stopping at Starship.

I've said it before and I'll say it again. They could have stopped at Falcon 9 and made bank and be remembered as heroes. Instead they are working on a Mars colonization rocket. That sounded almost as crazy back in 2016 when they announced it.

Granted, they aren't gonna get there on chemical fuels, so unless Musk has a stealth fusion startup we don't know about yet...

I can't seem to find a reference for this, so I don't know if I'm misremembering it, but I thought Shotwell once mentioned antimatter at a conference. And all the way back in 2017, SpaceX was trying to get a hold of nuclear material - which she just mentioned was hard. Though whatever SpaceX is working on in that regard isn't sufficient for interstellar travel - likely just NTRs and/or reactors, but they're not just sticking to chemical/ion.

Shotwell definitely said that she believed there would be a propulsion breakthrough "in my lifetime" to allow interstellar travel.

Meaning Proxima b.

Whether or not this actually comes to pass is irrelevant, some at SpaceX are definitely thinking well beyond interplanetary travel, even if it's only at a conceptual level. And who knows, if/when Starlink is making them money hand over fist, they'll start putting a bit of actual funding towards it like NIAC to see if they can move the needle on TRLs.

[Nuke]

i think elon may be jumping the gun here. i dont think we even are close to producing the perquisites for an interstellar mission, even an unmanned mission. you need:

1. propulsion, no engine no sane transfer duration. you need to get there before the ship is a broken down mess. see voyager 1. so you cant just use a really big fuel tank.

2. power. rtgs simply do not cut the mustard in either duration or power output. this also feeds back into 1 because you may need considerable power to say operate a fusion engine or plasma drive. if you have humans, increase power demands further.

3. systems with proven long operating life. humans have produced machines that in a good state of repair and with regular maintenance can last decades.  but every part of the ship must be designed thusly. parts must also be shelf stable as you may need them to work flawlessly after a hundred years of waiting all without humans to do regular servicing.

4. a really stable government. administration 0 may be willing to pump billions into an interstellar spacecraft, but administration 100 may not want to spend millions building the dish to receive the telemetry later on down the line. as for the private sector look at how well pan am has maintained its fleet in 2024. pan am who? were they a thing? you see my point. you might have to do some religious engineering to make sure people get the payout down the line,  because that's really the only institution humans have ever created which has legs.

Edited March 18 by Nuke