totm nov 2023 SpaceX Discussion Thread

[Beccab]

5 minutes ago, kerbiloid said:

Should try six.

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We're talking about the upper stage, not the booster. Upper stage is tested on the suborbital pad while the booster, which will do a 29 engine static fire, will be on the orbital pad

[kerbiloid]

4 minutes ago, Beccab said:

We're talking about the upper stage, not the booster.

The upper stages of N1 used 8 and 4 engines respectively, so the sixpack from the 1st one looks like a good compromise.

[magnemoe]

5 minutes ago, Beccab said:

We're talking about the upper stage, not the booster. Upper stage is tested on the suborbital pad while the booster, which will do a 29 engine static fire, will be on the orbital pad

Yes, I assume the test stand can only handle the 3 surface engines, also other issues testing the vacuum engines. on it like the hold down clamps will hit the engines. 
As I understand this is an issue with the first stage and the outer ring of engines. 
And starship can not be tested on the orbital pad who is designed to hold down the first stage, but the first stage engine ring is wider than 9 meter to so the hold down clamps has to be pulled back.
Something who will be exiting thinking on another failed launch. 

[Minmus Taster]

33 minutes ago, kerbiloid said:

Should try six.

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*Intense and dramatic N1 flashback

[tater]

Netflix thing seems OK. Dunno why they have a guy from Time magazine on all the time, I didn't realize anyone read Time any more .

[StrandedonEarth]

10 hours ago, kerbiloid said:

A bit later they will upgrade this to a stamp, But this needs time

… And stamping “OK” on it will break it…

[kerbiloid]

[snip]

47 minutes ago, StrandedonEarth said:

… And stamping “OK” on it will break it…

If they won't get tired of breathing on the stamp earlier.

Spoiler

 

[kerbiloid]

A wise advice: when somebody tells you that SH is N1, answer that not N1, but N1F. 
N1F was to be equipped with NK33 instead of NK15, and NK33 have been luckily tested by lifting Antares.

Edited September 6, 2021 by kerbiloid

[Lewie]

[snip]

Has there been any clue as to when the FAA/environmental review will be done?

[Beccab]

[snip]

No news on the FAA, but the FCC for the flight at least is now out and active. It lasts until 1st october and will definitely be extended

[Dman979]

Folks, some more content has been removed from the thread. It's not appropriate to make accusations against other users, and fighting isn't OK either. Please report posts that you think need moderator attention (and a big thank you to everyone who did!), but after that it's up to the Moderation Team to handle things.

I'm locking this thread temporarily to allow people to calm down. It'll reopen in three hours.

[tater]

They had the most issues on the nose cone—but that was literally the first attempt to apply them. The pins are normal to the surface at any given point (I assume), but the surface is constantly changing, so fit and technique are hardest in those regions (the glued tiles have different fit and technique issues because they are not forced to snap onto fixed pins, and I assume that is easier, not harder to deal with as a result).

I think the technique of actually applying them—quickly—will improve over time, this is the first 15,000 tiles, the next 15k will likely have fewer issues, and so forth.

It is important to remember that part of doing this is developing the system to do this moving forward. This is production design, not vehicle design. If it was all about this one vehicle, they would be up there spending as long as it took with micrometers to get every tile just so. They wanted to see how people doing regular labor could just slap those on—maybe that would be good enough... then they decided there were too many failures, they are like trying to figure out what went right with the "OK" tiles, and what was the issue with the red/green marked ones. Slight pin variation (possibly due to substrate variations, like dents, etc)? Maybe the pin channels need to be altered to allow more variation in some way (tough, I would think)? Maybe pin changes?

Edited September 6, 2021 by tater

[Beccab]

[JoeSchmuckatelli]

22 minutes ago, Beccab said:

Not sure - but won't this be the largest thing we've ever attempted controlled reentry with? 

 

Note: not considering things like Skylab or spent stages

[tater]

9 minutes ago, JoeSchmuckatelli said:

Not sure - but won't this be the largest thing we've ever attempted controlled reentry with? 

Size wise, for sure. Almost certainly mass as well, because even if on the light end of what the dry mass could be, it will still also have what, 20t+ of landing props?

[Beccab]

B4 rollout tomorrow!

[spacehex]

1 hour ago, tater said:

They had the most issues on the nose cone—but that was literally the first attempt to apply them. The pins are normal to the surface at any given point (I assume), but the surface is constantly changing, so fit and technique are hardest in those regions (the glued tiles have different fit and technique issues because they are not forced to snap onto fixed pins, and I assume that is easier, not harder to deal with as a result).

I think the technique of actually applying them—quickly—will improve over time, this is the first 15,000 tiles, the next 15k will likely have fewer issues, and so forth.

It is important to remember that part of doing this is developing the system to do this moving forward. This is production design, not vehicle design. If it was all about this one vehicle, they would be up there spending as long as it took with micrometers to get every tile just so. They wanted to see how people doing regular labor could just slap those on—maybe that would be good enough... then they decided there were too many failures, they are like trying to figure out what went right with the "OK" tiles, and what was the issue with the red/green marked ones. Slight pin variation (possibly due to substrate variations, like dents, etc)? Maybe the pin channels need to be altered to allow more variation in some way (tough, I would think)? Maybe pin changes?

I know there's a thermal blanket thing lining under the hex TUFROC tiles, but I can't wait to see how the tiles with the slightly loose spacing between them perform at reentry. 

[sevenperforce]

6 hours ago, spacehex said:

I know there's a thermal blanket thing lining under the hex TUFROC tiles, but I can't wait to see how the tiles with the slightly loose spacing between them perform at reentry. 

They’re not TUFROC but otherwise yes I agree. 

[michal.don]

11 hours ago, tater said:

Size wise, for sure. Almost certainly mass as well, because even if on the light end of what the dry mass could be, it will still also have what, 20t+ of landing props?

I'm not sure about that - do we know how heavy the S20 is? I believe the "final" starhip will be around 150 t, but what about this one? Will it still beat the 80-ish tons the space shuttle had?

[Beccab]

So, there is another fit test (with full stack), then 40 days where stacking isn't possible where they will presumably start testing at least S20 and continue working on the chopstick arms

[RCgothic]

1 hour ago, michal.don said:

I'm not sure about that - do we know how heavy the S20 is? I believe the "final" starhip will be around 150 t, but what about this one? Will it still beat the 80-ish tons the space shuttle had?

We need to be clear what we mean.

From Tim Dodd's interview with Elon, SN 20 with heat shield shouldn't be much more than 100t dry. Note that the goal is very much to reduce this.

In terms of mass to LEO, final Starship version might be 80t dry, 30t landing propellant, 100+t payload. 210+t to LEO.

The space shuttle weighed about 78t dry, 110t wet and carried payloads of up 24t. The wiki entry for heaviest spacecraft puts it at 122.7t max on orbit (onboard fuel is expended to establish orbit). Being generous, the external tank is nearly at orbital velocity, and weighs 35t empty. Bringing it to orbit is estimated to cost 5t payload, so that's an extra +30t. 150t ish to LEO for the space shuttle assuming you count all the bits that aren't especially useful (maybe you want to turn an external tank into a fuel depot or wet workshop, who knows).

So starship will weigh around the same as the site orbiter dry, but place vastly more mass in LEO.

 

As a point of interest I've seen an analysis that suggests Saturn V INT-21 would probably have been capable of around 177t to LEO inclusive of the S-II stage (185kmx200km @ 28.5deg).

 

[Beccab]

1 minute ago, RCgothic said:

As a point of interest I've seen an analysis that suggests Saturn V INT-21 would probably have been capable of around 177t to LEO inclusive of the S-II stage (185kmx200km @ 28.5deg).

At this point I don't know what would have been better, if a Shuttle external tank wet workshop or an S-II wet workshop. Such a missed opportunity

[michal.don]

18 minutes ago, RCgothic said:

We need to be clear what we mean.

I should have made it clearer, I specifically meant the "largest thing we've tried to reenter" bit. Of course Starship would be much heavier when reaching LEO, but it seemed to me the reentering mass would be quite similar. But then again, in some cases the Starship might reenter and land with significant payloads (crew?) and become the heaviest thing ever reentered with significant margins.

[Beccab]

7 minutes ago, michal.don said:

I should have made it clearer, I specifically meant the "largest thing we've tried to reenter" bit. Of course Starship would be much heavier when reaching LEO, but it seemed to me the reentering mass would be quite similar. But then again, in some cases the Starship might reenter and land with significant payloads (crew?) and become the heaviest thing ever reentered with significant margins.

Uncrewed starship should be about 7 tons heavier than the crewed Shuttle (plus the landing propellant), so the crewed variant will definitely be much heavier

[michal.don]

3 minutes ago, Beccab said:

Uncrewed starship should be about 7 tons heavier than the crewed Shuttle (plus the landing propellant), so the crewed variant will definitely be much heavier

Thanks for the clarification, I guess we'll see the record broken several times in the near future then....