SpaceX Starship - IFT-4 - Starbase TX - Pre-Launch Preparations Thread

[ecarfan]

NSF said it only took about 40 minutes for prop load, right? That is pretty fast.

There appeared to be a lengthy hold with the tanks full and now detanking. No spin prime or deluge system test.

Beautiful sight.

 

[Electroman]

Dos the count down go down to T-1 minute, in this exercise ?

 

[ecarfan]

Dos the count down go down to T-1 minute, in this exercise ?

As far as I know, outsiders do not have access to the countdown clock that SpaceX is running during a wet dress, so the NSF commentators make educated guesses as to what the T- number is.

 

[ecarfan]

Ship was destacked yesterday but remains next to the OLM and they are doing some work on the tiles. Maybe it won’t go back to the Megabay.

 

[ecarfan]

ars Technica summary of what the goals are for IFT-4. We already know most of it, but this I did not know (article source is Lisa Watson-Morgan, manager of NASA's Human Landing System):

SpaceX is not planning to attempt a Raptor engine restart on the next Starship test flight. Eventually, SpaceX must demonstrate this capability for future Starships to drop out of orbit and return to Earth, or to head to the Moon and take off from the lunar surface. Achieving an in-orbit engine restart—necessary to guide Starship toward a controlled reentry—is a prerequisite for future launches into a stable higher orbit, where the ship could loiter for hours, days, or weeks to deploy satellites and attempt refueling.

The priority is a successful reentry. If I understand correctly, while Raptor restart is needed for a controlled reentry which is an IFT-4 objective, since the planned not-quite-orbital flight trajectory ensures reentry without a restart they aren’t going to do a restart.

 

[scaesare]

ars Technica summary of what the goals are for IFT-4. We already know most of it, but this I did not know (article source is Lisa Watson-Morgan, manager of NASA's Human Landing System):


The priority is a successful reentry. If I understand correctly, while Raptor restart is needed for a controlled reentry which is an IFT-4 objective, since the planned not-quite-orbital flight trajectory ensures reentry without a restart they aren’t going to do a restart.

That kind of surprised me when I read it... doesn't seem the SpaceX way. She also said: "For Flight 4, it's mostly going to be a repeat of Flight 3 without the propellant transfer, without the Pez door open, without the other items that SpaceX was working to demonstrate,".

She's NASA. not SpaceX, bit I assume she knows what she's talking about.

 

[JB47394]

That kind of surprised me when I read it... doesn't seem the SpaceX way.

Assume that the IFT-3 mission profile demonstrated a problem that they cannot eliminate because it is inherent in the flight hardware, and Ship 29 is the same design as Ship 28. Assume also that the problem compromises the stability of reentry. They really want a stable reentry, so they're discarding anything that could possibly interfere with it.

For stuff like the payload door and such, they may have learned that the way they're trying to do it is stupid, so they're going back to the drawing board and figuring out something new for a future flight.

 

[scaesare]

Assume that the IFT-3 mission profile demonstrated a problem that they cannot eliminate because it is inherent in the flight hardware, and Ship 29 is the same design as Ship 28. Assume also that the problem compromises the stability of reentry. They really want a stable reentry, so they're discarding anything that could possibly interfere with it.

For stuff like the payload door and such, they may have learned that the way they're trying to do it is stupid, so they're going back to the drawing board and figuring out something new for a future flight.

Yeah, I'm sure that's part (or most) of it. I also expect that there's tons of small design changes that don't warrant a mention, but SX has had a history of using the opportunity to try stuff, even if they don't expect it succeed just to gather data.

Hopefully they are at least testing some improved tile attachment method we don't yet know about.

 

[Electroman]

Isn't relighting and slowing down the Ship a great way to reduce heat generation during reentry, and thus give a high probability of successful testing o fheat shields in the correct temp profile?.

Rather shouldn't reentry-burn be a part of every reentry ?

 

[ecarfan]

She's NASA. not SpaceX, bit I assume she knows what she's talking about.

As the HLS director she is of course closely following everything going on with Starship and I’m confident she is conveying accurate information.

 

[ecarfan]

Rather shouldn't reentry-burn be a part of every reentry ?

My not-a-rocket-scientist answer is that for the IFT mission profile, where the ship is not quite achieving orbit and the trajectory ensures a return over the Indian Ocean, a re-entry burn is not required. The ship is not getting to LEO.

During IFT-3 the plan was to do a brief relight just as a test to see if it works correctly in zero G, since on future flights where the ship gets to LEO such a relight burn will be needed.

 

[mongo]

Isn't relighting and slowing down the Ship a great way to reduce heat generation during reentry, and thus give a high probability of successful testing o fheat shields in the correct temp profile?.

Rather shouldn't reentry-burn be a part of every reentry ?

Sure, but that's a huge performance hit, and slower means not having the correct energy profile.

 

[ecarfan]

The ship is getting a lot of attention right now. And what exactly does “Flight closure scheduled for June 1” mean?

 

[JB47394]

And what exactly does “Flight closure scheduled for June 1” mean?

I think they're going by the time of the road closure: 12am to 2pm. I don't believe that's used for any other activity at Starbase.

 

[ecarfan]

I think they're going by the time of the road closure: 12am to 2pm. I don't believe that's used for any other activity at Starbase.

Thanks, it’s just odd that NSF used the word “Flight” unless they think that IFT-4 could be tentatively planned for that date.

 

[JB47394]

Thanks, it’s just odd that NSF used the word “Flight” unless they think that IFT-4 could be tentatively planned for that date.

I think they're hoping. Elon made his "two weeks" tweet on the 20th. June 1st would be the 12th day.

I'm waiting for TFRs and NOTAMs and such.

 

[mongo]

I think they're hoping. Elon made his "two weeks" tweet on the 20th. June 1st would be the 12th day.

I'm waiting for TFRs and NOTAMs and such.

More than hope, road closure is for flight activities:

I have ordered the closure of Boca Chica Beach and Hwy 4 for the purpose of protecting Public Health and Safety during SpaceX flight testing activities on June 1, 2024, in the time period between 12:00 a.m. C.S.T. to 2:00 p.m. C.S.T. and in the alternative on June 2, 2024 or June 3, 2024, from 12:00 a.m. C.S.T. to 2:00 p.m. C.S.T., of the same day. Should SpaceX not complete its planned flight-testing activity on June 1, 2024, then SpaceX may use the alternate dates to complete its testing activities,” Treviño stated

Contrast to May 28:

“I have ordered the closure of Boca Chica Beach and Hwy 4 for the purpose of protecting Public Health and Safety during SpaceX non-flight testing activities on May 28, 2024, in the time period between 5:00 a.m. C.S.T. to 5:00 p.m. C.S.T. and in the alternative on May 29, 2024 or May 30, 2024, from 5:00 a.m. C.S.T. to 5:00 p.m. C.S.T., of the same day. Should SpaceX not complete its planned non-flight testing on May 28, 2024, then SpaceX may use the alternate dates to complete its testing activities,” Treviño stated

 

[ecarfan]

More than hope, road closure is for flight activities

Thanks, that sounds promising! Maybe SpaceX is getting private communications from the FAA that the launch license will be issued by the end of May.

 

[JB47394]

More than hope, road closure is for flight activities:

Notice to Mariners is up. That's confirmation enough for me to believe.

On June 1, 2024, between 7:00 a.m. and 11:00 a.m., rocket launching operations are scheduled to take place near Boca Chica, TX. Back-uplaunch dates and times include each day following June 1, 2024, between 7:00 a.m. and 11:00 a.m., until conditions permit the launch. Mariners operating offshore in waters east of Brownsville, Texas, are advised of the scheduled rocket launching activities and associated hazardous areas which may impact navigation interests.

This is the resource I use to follow preparations:

Starship

Keep up to date with all of the Starship action.

nextspaceflight.com

 

[scaesare]

Figures... I gotta be out that day...