totm nov 2023 SpaceX Discussion Thread

[RedKraken]

"Wouldn't call what BFS has a delta wing. It is quite small (and light) relative to the rest of the vehicle and is never actually used to generate lift in the way that an aircraft wing is used.

It's true purpose is to "balance out" the ship, ensuring that it doesn't enter engines first from orbit (that would be really bad), and provide pitch and yaw control during reentry."

Edited October 14, 2017 by RedKraken

[sh1pman]

Just now, RedKraken said:

"Wouldn't call what BFS has a delta wing. It is quite small (and light) relative to the rest of the vehicle and is never actually used to generate lift in the way that an aircraft wing is used.

It's true purpose is to "balance out" the ship, ensuring that it doesn't enter engines first from orbit (that would be really bad), and provide pitch and yaw control during reentry."

I can't really see how it would give any yaw control.

[RedKraken]

"Best mass ratio is achieved by not building a box in a box. The propellant tanks need to be cylindrical to be remotely mass efficient and they have to carry ascent load, so lowest mass solution is just to mount the heat shield plates directly to the tank wall."

[Ultimate Steve]

Elon has admitted to drinking whiskey while doing the AMA. That might explain some of the answers...

[WinkAllKerb'']

in/out

https://www.youtube.com/watch?v=mBJkeQunyzg

 

[sh1pman]

"The "vacuum" or high area ratio Raptors can operate at full thrust at sea level. Not recommended".

Edited October 14, 2017 by sh1pman

[Ultimate Steve]

Over on the actual SpaceX reddit, a new discussion has arisen. It seems like SpaceX has attained a launch permit for November 10 from the Cape for a Falcon 9 with an RTLS landing. The only thing is, there's no known payload that matches that description. CRS-13 isn't until late November. We know it's not FH, unfortunately.

In the comments two people have revealed the leaked information that the codename of this launch is Zuma. We have no idea what it is, but it's probably NRO related.

*dramatic*

[tater]

I posted about that hours ago, and there has been tons of speculation on reddit and NSF.

One that might be interesting, given the claimed commercial nature of the payload would be a commsat to stake out specific wavelengths. Being there apparently matters, so throwing a single sat up, even if not part of a useful constellation might grab the required frequency.

[_Augustus_]

1 hour ago, Ultimate Steve said:

Over on the actual SpaceX reddit, a new discussion has arisen. It seems like SpaceX has attained a launch permit for November 10 from the Cape for a Falcon 9 with an RTLS landing. The only thing is, there's no known payload that matches that description. CRS-13 isn't until late November. We know it's not FH, unfortunately.

In the comments two people have revealed the leaked information that the codename of this launch is Zuma. We have no idea what it is, but it's probably NRO related.

*dramatic*

I don't think it's NRO or other government stuff. It is mentioned in the document that this will be a RTLS, which doesn't correspond to a GTO launch with a heavy payload. And we'd still hear about it officially from SpaceX.

That being said, I don't think it's a normal commercial launch either - a heavy payload to GTO would again prevent RTLS, they already have a TON of customers already backlogged to 2018, and again we'd hear about it officially.

If it is an internal SpaceX payload (which would explain the total silence from SpaceX), it's a little odd that they are using a new booster (maybe it'll be the first Block 5?), and it can't be Starlink because they're still doing ground tests and that would be a big GTO payload.

So if it's not NRO, not a commercial comsat launch, and not Starlink, what is it? Some of the theories I've been reading, and my thoughts on them:

• DragonLab, maybe with a mannequin wearing a SpaceX suit for depressurization testing - Possible, but they'd be hyping it up to potential future customers and it wouldn't have this weird codename
• ITS aerodynamic boilerplate - No good reason to be using a new booster for this kind of flight, nor a second stage (the document states that the rocket will have a second stage)
• Google Lunar xPrize SpaceIL - Explains secrecy (codename seems weird but whatever), payload is tiny enough to allow RTLS
• Dragon 2 flight - In-flight abort test would use a refurbished booster, and unmanned to ISS wouldn't be kept a secret. If SpaceX is really crazy I guess maybe a non-NASA manned launch to LEO (no ISS docking) with Elon/engineers as crew is possible, and could explain the secrecy.

I honestly think it's either SpaceIL, a MANNED non-NASA Crew Dragon flight to totally surprise the entire world, or something else we don't know about.

 

Edited October 15, 2017 by _Augustus_

[tater]

I think a combo with a block 5 might be a thing (new booster as a test).

[_Augustus_]

3 minutes ago, tater said:

I think a combo with a block 5 might be a thing (new booster as a test).

What do you mean?

[tater]

3 minutes ago, _Augustus_ said:

What do you mean?

Any of your suggestions, or something else, but also throw in a block 5 test?

[Ultimate Steve]

10 minutes ago, _Augustus_ said:

•  

I honestly think it's either SpaceIL, a MANNED non-NASA Crew Dragon flight to totally surprise the entire world, or something else we don't know about.

SpaceIL would be plausible, but no reason to use a new booster. Manned Crew Dragon before unmanned is probably not happening... Last I heard the CD's were still under construction. That would be amazing, though.

[_Augustus_]

Just now, Ultimate Steve said:

SpaceIL would be plausible, but no reason to use a new booster. Manned Crew Dragon before unmanned is probably not happening... Last I heard the CD's were still under construction. That would be amazing, though.

No reason, but they did order an F9 a really long time ago, before reuse was a thing. 

With regards to manned D2, it *probably* isn't happening, but people on NSF are saying that this has to be some sort of stunt by SpaceX, and a surprise manned Dragon flight would do it.

[tater]

Can block 5 do gto, and still RTLS?

[_Augustus_]

8 minutes ago, tater said:

Can block 5 do gto, and still RTLS?

According to some really rough math it should be able to bring maybe 2 tons to GTO with RTLS. Since a Moon launch trajectory isn't much more delta-v, the SpaceIL lander sounds like it'd work with RTLS. But definitely no big GTO/similar orbit government/commercial sats.

Edited October 15, 2017 by _Augustus_

[CatastrophicFailure]

Hmm...

According to this article, CRS 13 is slated to go up from Pad 40. 

[StupidAndy]

well my question didn't get answered in the AMA, oh well

wasn't particularly interesting, just something about launchpads and such

[Ultimate Steve]

1 hour ago, StupidAndy said:

well my question didn't get answered in the AMA, oh well

wasn't particularly interesting, just something about launchpads and such

Neither did mine, but let's be honest, thousands of questions were asked and 20 were answered.

 

Also I just had an idea. If circumlunar transport is needed and the BFR isn't ready for some reason, you could stick an X-37 on a Falcon heavy. If you were willing to deal with cramped quarters for a week or two, you could go to low lunar orbit and back, using 90% hardware that currently exists.

Actually, if you were willing to go expendable, you could just use a Falcon 9!

As far as math goes, FH can get 25mt to GTO. There's no mention of moon numbers, but the Mars numbers are 16mt, so somewhere around 20 to TLI seems right. The X-37, however, would be 5-6t, which is really light. X-37 has 4km/s in fuel on board (!) according to what we know about it. To go from TLI to LLO is about 1km/s. There and back is 2km/s, and you get 2km/s to brake into a lower orbit, meaning X-37 re-enters only 10% faster than it usually does.

But, if you could make the X-37 able to re-enter at higher speeds, you could theoretically carry up to 1t of payload... I mean, let's see. A person with a spacesuit is, what, 200kg at worst? Optimizable to 150kg. If you build an incredibly barebones lander (like, EVA seat barebone) with a specific impulse of, say, 320, with 50kg for the tanks, engine, etc, you could have a dry mass of 200kg and a wet mass of 700kg, and be able to make a trip from LLO to the lunar surface and back...

Plus 300kg for supplies and a living space aboard an X-37, there's your 1000kg. You could even leave the lander in LLO on the first flight and come back with just fuel on the second!

 

If it wasn't late, I'd open RO and try to build this...

Edited October 15, 2017 by Ultimate Steve

[insert_name]

20 minutes ago, Ultimate Steve said:

Neither did mine, but let's be honest, thousands of questions were asked and 20 were answered.

 

Also I just had an idea. If circumlunar transport is needed and the BFR isn't ready for some reason, you could stick an X-37 on a Falcon heavy. If you were willing to deal with cramped quarters for a week or two, you could go to low lunar orbit and back, using 90% hardware that currently exists.

Actually, if you were willing to go expendable, you could just use a Falcon 9!

As far as math goes, FH can get 25mt to GTO. There's no mention of moon numbers, but the Mars numbers are 16mt, so somewhere around 20 to TLI seems right. The X-37, however, would be 5-6t, which is really light. X-37 has 4km/s in fuel on board (!) according to what we know about it. To go from TLI to LLO is about 1km/s. There and back is 2km/s, and you get 2km/s to brake into a lower orbit, meaning X-37 re-enters only 10% faster than it usually does.

But, if you could make the X-37 able to re-enter at higher speeds, you could theoretically carry up to 1t of payload... I mean, let's see. A person with a spacesuit is, what, 200kg at worst? Optimizable to 150kg. If you build an incredibly barebones lander (like, EVA seat barebone) with a specific impulse of, say, 320, with 50kg for the tanks, engine, etc, you could have a dry mass of 200kg and a wet mass of 700kg, and be able to make a trip from LLO to the lunar surface and back...

Plus 300kg for supplies and a living space aboard an X-37, there's your 1000kg. You could even leave the lander in LLO on the first flight and come back with just fuel on the second!

 

If it wasn't late, I'd open RO and try to build this...

A week in a spacesuit with minimal suppliers on a spacecraft that isn't man rated without an abort system? I'm sure you're going to be overwhelmed with volunteers.

Edited October 15, 2017 by insert_name

[Steel]

2 hours ago, Ultimate Steve said:

Neither did mine, but let's be honest, thousands of questions were asked and 20 were answered.

 

Also I just had an idea. If circumlunar transport is needed and the BFR isn't ready for some reason, you could stick an X-37 on a Falcon heavy. If you were willing to deal with cramped quarters for a week or two, you could go to low lunar orbit and back, using 90% hardware that currently exists.

Actually, if you were willing to go expendable, you could just use a Falcon 9!

As far as math goes, FH can get 25mt to GTO. There's no mention of moon numbers, but the Mars numbers are 16mt, so somewhere around 20 to TLI seems right. The X-37, however, would be 5-6t, which is really light. X-37 has 4km/s in fuel on board (!) according to what we know about it. To go from TLI to LLO is about 1km/s. There and back is 2km/s, and you get 2km/s to brake into a lower orbit, meaning X-37 re-enters only 10% faster than it usually does.

But, if you could make the X-37 able to re-enter at higher speeds, you could theoretically carry up to 1t of payload... I mean, let's see. A person with a spacesuit is, what, 200kg at worst? Optimizable to 150kg. If you build an incredibly barebones lander (like, EVA seat barebone) with a specific impulse of, say, 320, with 50kg for the tanks, engine, etc, you could have a dry mass of 200kg and a wet mass of 700kg, and be able to make a trip from LLO to the lunar surface and back...

Plus 300kg for supplies and a living space aboard an X-37, there's your 1000kg. You could even leave the lander in LLO on the first flight and come back with just fuel on the second!

 

If it wasn't late, I'd open RO and try to build this...

I mean... It might be 'possible', but considering the X-37 is unmanned the only internal space you have available is the payload bay with no life support systems (or windows for that matter). You'd basically ride to the moon in a large space coffin

[Nibb31]

I think ZUMA could be a followup for PAN and CLIO, which were both codenames for top-secret launches with an unknown payload. They ended up being identified as Nemesis-1 and Nemesis-2, which are SIGINT birds that are supposed to shadow other countries' satellites to intercept their comms. This could be Nemesis-3 or a followup program.

[KSK]

6 hours ago, Ultimate Steve said:

Over on the actual SpaceX reddit, a new discussion has arisen. It seems like SpaceX has attained a launch permit for November 10 from the Cape for a Falcon 9 with an RTLS landing. The only thing is, there's no known payload that matches that description. CRS-13 isn't until late November. We know it's not FH, unfortunately.

In the comments two people have revealed the leaked information that the codename of this launch is Zuma. We have no idea what it is, but it's probably NRO related.

*dramatic*

It's the test flight for Zumba, which will be the all singing, all dancing version.

 

I'll get my coat.

[Elthy]

Someone compiled a list of all answered questions, way easier to read than the whole thread:

https://www.reddit.com/r/space/comments/76e79c/i_am_elon_musk_ask_me_anything_about_bfr/dodhawf

[Nibb31]

11 hours ago, sh1pman said:

I can't really see how it would give any yaw control.

Have you ever tried skiing ? The two flaps are very similar to the way you control your trajectory on skis by pushing your heels.