totm nov 2023 SpaceX Discussion Thread

[SunlitZelkova]

1 hour ago, Ultimate Steve said:

Given the MSR news... I'm not saying this is a good idea and I'm not saying it will happen, but proposing a manned Starship mission to complete Mars Sample Return is a completely on brand thing for SpaceX to do.

Would be quite the plot twist but the 21st century of space exploration has been filled with so many plot twists already that I doubt anything would surprise me at this point.

The issue is that Artemis is currently eating up funding right now.

A crewed mission would be much more expensive than a robotic one.

On the other hand, I could see “Polaris 11” funded by Isaacman being the first crewed mission to Mars. But I highly doubt government space agencies will have much money to spare to partake in such a mission for quite awhile. All focus is on the Moon.

[Ultimate Steve]

This could either go here in the MSR thread (wait hold on, do we have an MSR thread?), but since we are talking MSR already I thought I'd bring it up, as the subject matter is both MSR and Red Dragon/SpaceX related. https://news.ycombinator.com/item?id=26274117

That's an old post from someone who was working at NASA around the same time as Red Dragon was being proposed for Mars Sample Return. While it is an anonymous personal account and should be taken with at least a few grains of salt, if true, the contents are interesting. The OP discusses how company and government politics and not internal cancellation prevented Red Dragon from happening. I recommend reading the whole thing.

TLDR, if the person who made this post is to be believed:

• SpaceX proposed (or planned to propose) Red Dragon 3 times
• The first attempt  (2013) was not a sample return and was shot down by NASA/the government (rumor)
  • Falcon 9 had only flown 4-7 times at that point depending on when in 2013 we are, SpaceX was very much still the underdog
  • NASA didn't want a crew rated capsule to be seen going to Mars and propulsively landing when Orion couldn't do any of that
  • The main rumor is that some higher ups in the government (think shelby types) threatened to withhold future CRS and Commercial Crew and other contracts (which SpaceX was very much trying to get) if Red Dragon happened
• The second attempt (2014 or 2015, post uses both years) was a sample return but was shot down by JPL
  • JPL is protective of their role in planetary exploration
  • JPL had previously scheduled their missions to assure a steady stream of funding
  • JPL did that with MSR as well, the fact that it is 3 missions is part of that
  • MSR going to anyone other than JPL would be a severe threat to JPL's prestige and funding
  • JPL tried very hard to discredit Red Dragon via numerous (often underhanded) methods
• OP notes that neither proposal was actually submitted, and posits that there aren't many other reasons why you would prepare a proposal and not submit it
• OP doesn't know much about the third attempt (2016)
  • Obviously it didn't happen
  • This is when SpaceX pulled the plug and decided to go all in on Starship (ITS at the time)

[darthgently]

The more I think about it, the more I think SpaceX, and other launch providers, should list with DoorDash as "drivers" with destinations only in orbit.  We could crowdfund a pizza delivery to the ISS.  For world peace

[mikegarrison]

2 hours ago, Ultimate Steve said:

and posits that there aren't many other reasons why you would prepare a proposal and not submit it

Having done this before, many times, there are many reasons why someone might prepare a proposal like this and not submit it. Number 1 is that your own management, who asked for the proposal in the first place, changes their mind either once they see it or just because time has passed and things have changed.

[tater]

Quote

SpaceX is targeting Wednesday, April 17 for a Falcon 9 launch of 23 Starlink satellites to low-Earth orbit from Launch Complex 39A (LC-39A) at NASA’s Kennedy Space Center in Florida. Liftoff is targeted for 5:26 p.m. ET, with backup opportunities available until 9:24 p.m. ET. If needed, additional opportunities are also available on Thursday, April 18 starting at 5:05 p.m. ET.

 

[tater]

 

5 min

4 min

 

[tater]

Feed dropped. NSF captured a screen shot of the landed booster

 

[Spaceception]

Saw a tweet earlier that said something along the lines of "we live in a world where it's more likely for a launch feed to crash than a rocket landing itself."

[tomf]

13 hours ago, Spaceception said:

Saw a tweet earlier that said something along the lines of "we live in a world where it's more likely for a launch feed to crash than a rocket landing itself."

I know what they mean, but it just occurred to me that if you were to ask someone in the 60 which would happen first, routine landing of rocket first stages or almost everyone on earth carrying a device that would enable them to video call anyone else on earth they would have thought the rocket thing more likely 

Weird how perceptions change .

[StrandedonEarth]

Okay, so a booster airframe has made 20 flights. Does it still have any of its original Merlins?  What is the most flights for a Merlin engine?

[AckSed]

50 minutes ago, StrandedonEarth said:

Okay, so a booster airframe has made 20 flights. Does it still have any of its original Merlins?  What is the most flights for a Merlin engine?

Says here it was carrying a fleet-leader 1D that had done 22 flights: https://www.americaspace.com/2024/02/23/spacex-launches-record-setting-merlin-engine-returns-record-tying-booster-to-safe-landing/

[tater]

Apparently there was just a launch.

 

 

[tater]

Constrains IFT-4 to NET April 25 (no later than Oct 25)

 

[Flavio hc16]

Hmmm

 

May the Force (4th) be with you!

[CatastrophicFailure]

On 4/15/2024 at 2:29 PM, Ultimate Steve said:

Given the MSR news... I'm not saying this is a good idea and I'm not saying it will happen, but proposing a manned Starship mission to complete Mars Sample Return is a completely on brand thing for SpaceX to do.

Would be quite the plot twist but the 21st century of space exploration has been filled with so many plot twists already that I doubt anything would surprise me at this point.

Only if they bring back Spirit & Opportunity too. 

[GuessingEveryDay]

Found an interesting article about a prototype engine called LEET-1337.

https://www.nextbigfuture.com/2023/09/beyond-the-spacex-raptor-engine-is-the-breakthrough-spacex-leet-1337-engine.html

TL;DR The LEET engine will be 1100 kg and has a thrust of 320 tons with a chamber pressure of 450. For comparison, Raptor 3 is 1400 kg, only 280 tons, and 400.

Not sure how this is accomplished, but it was mentioned in Walter Isaascon's biography of Elon Musk that they were stripping as much weight as possible, maybe combining pumps with the injectors.

A couple redditors think they might stick a turbine between the combustion chamber and the nozzle.

Very interesting!

[bigyihsuan]

16 minutes ago, GuessingEveryDay said:

A couple redditors think they might stick a turbine between the combustion chamber and the nozzle.

A turbine in the engine exhaust seems absolutely wacky! How is it gonna be cooled when it's constantly blasted by rocket exhaust for minutes at a time?

[Ultimate Steve]

Wait, that's not a meme engine? Huh. Scrolled past it on reddit assuming it was a meme. I knew SpaceX was the company most likely to name their engine after a meme, but I didn't think it would be this overt.

Engine turbine would be more akin to how jet engines work, but there's probably many very good reasons why it hasn't been done before.

[magnemoe]

2 minutes ago, Ultimate Steve said:

Wait, that's not a meme engine? Huh. Scrolled past it on reddit assuming it was a meme. I knew SpaceX was the company most likely to name their engine after a meme, but I didn't think it would be this overt.

Engine turbine would be more akin to how jet engines work, but there's probably many very good reasons why it hasn't been done before.

Yes jet engines run lean on 20% oxygen in the atmosphere. Rocket engines uses lox and fuel, mixed together, great care has to be taken to  not melt the chamber. Putting an turbine in there is idiotic hard.  
All turbo pumps is inefficient by design as you can not run them like rocket engines as you melt the turbine and this is just to power the pumps. Now you could have the inefficient burned mix feed into the engine chamber, eliminating the loss if you can handle the higher pressure.  Obviously if you could run an turbo pump as an rocket engine you could just use it as an smaller rocket engine at the side who would be much easier but still very hard as none has done it.
Now you might pull this off on an smaller hydrolox turbo pump, burn it oxygen rich, use LH2 to cool the turbine by pumping it trough blades for cooling,  then an second chamber before the nozzle and exhaust is fuel rich. You can use this for roll control and does not get usual open cycle losses even if open cycle. Its not something SpaceX would make. 

[GuessingEveryDay]

1 hour ago, bigyihsuan said:

A turbine in the engine exhaust seems absolutely wacky! How is it gonna be cooled when it's constantly blasted by rocket exhaust for minutes at a time?

I'm guessing they stick the injectors to push the turbine and push the exhaust up. The exhaust then is ignited for the last time and goes down through the turbine again. This way the turbine is still cooled and could increase chamber pressure and thrust.

[GuessingEveryDay]

3 hours ago, GuessingEveryDay said:

I'm guessing they stick the injectors to push the turbine and push the exhaust up. The exhaust then is ignited for the last time and goes down through the turbine again. This way the turbine is still cooled and could increase chamber pressure and thrust.

[Nuke]

this thing wasn't pushed out on april fools day was it?

[mikegarrison]

10 hours ago, magnemoe said:

Yes jet engines run lean on 20% oxygen in the atmosphere. Rocket engines uses lox and fuel, mixed together, great care has to be taken to  not melt the chamber.

Jet engines could easily melt their own combustion chamber, if not for the engineering to make sure that doesn't happen. They are not as different as you seem to think. But the typical jet engine combustor is much more complicated than a rocket engine combustor, because it has constraints that a rocket engine combustor doesn't have. Emissions control, for example. There are no emissions rules for rocket engines.

Edited April 21 by mikegarrison

[CatastrophicFailure]

Good article with some equally interesting discussion down in the comments. TL:DR due to potential delays with Starship, Orion’s heat shield, et al, NASA may be considering an Apollo-9-esq mission of putting Orion into LEO to dock with a stripped-down Starship for habitability and other tests. 

Or, if you believe the conspiracies, a “camel’s nose under the tent” to obviate SLS entirely… 

Spoiler

iwanttobelieve.gif

derp… here’s the article…

https://arstechnica.com/space/2024/04/nasa-may-alter-artemis-iii-to-have-starship-and-orion-dock-in-low-earth-orbit/?comments=1&comments-page=1

 

Edited April 21 by CatastrophicFailure

[magnemoe]

17 hours ago, mikegarrison said:

Jet engines could easily melt their own combustion chamber, if not for the engineering to make sure that doesn't happen. They are not as different as you seem to think. But the typical jet engine combustor is much more complicated than a rocket engine combustor, because it has constraints that a rocket engine combustor doesn't have. Emissions control, for example. There are no emissions rules for rocket engines.

Jet engines bleed air trough the turbine blades to cool them, my idea was to do this with hydrogen. And yes early jet engines just lasted some hours  
And jet engines are more complex in many ways as you are burning air not pure oxygen, air pressure variations and as you say environmental factors including noise, also orders of magnitude longer flight times. 
I'm sure its lots of engines on long distance flight who has burned for longer in an single flight than shuttle or falcon 9 engines has burned totally but jet engine then does this the next day