totm nov 2023 SpaceX Discussion Thread

[tater]

2 minutes ago, sh1pman said:

BO may take some commercial payloads (that weren’t taken by Starship for whatever reason), but ULA has political power. It’ll get by just making SLS core stages for years and launching Air Force payloads.

Core stage is just Boeing, not ULA.

Yeah, there is politics for gov launches---and some good reasoning there as well, wanting to have multiple launch providers is a good thing. Still, if Blue has very competitive pricing, then SpaceX has to follow. This is a good thing, honestly, as it will drive cost reduction. It is really required to drive cost reduction. SpaceX has to only barely cut prices to compete with ULA, et al.

[Lukaszenko]

On 10/1/2019 at 5:07 PM, tater said:

I think that SpaceX is open enough to data that they will eventually end up with pure space vehicles, and Earth<---->LEO vehicles.

Take a variant Starship. Remove all TPS. Remove fins. Jettison the entire fairing. You have a cylinder in space now that still has attitude control, solar power, and can be refilled with other Starships. You have a tug/ferry very much in the spirit of the original NASA STS concept (before shuttle stole the name of what was meant to be a SYSTEM of multiple vehicles). What's the dry mass of Starship minus all that stuff? 75 tons? Less?

Could Super Heavy make orbit with no usable payload? If so, launch it anyway and you end up with something even better. Subtract the fins and legs, and maybe replace a couple engines with vac variants to optimise.

You can then take the whole RTLS concept to the next level, where the launch site is low-Earth orbit. I wonder how fast that could get you to Mars?

[Serpens Solidus]

I found this beauty somewhere: 

 

[tater]

3 minutes ago, Lukaszenko said:

Could Super Heavy make orbit with no usable payload? If so, launch it anyway and you end up with something even better. Subtract the fins and legs, and maybe replace a couple engines with vac variants to optimise.

You can then take the whole RTLS concept to the next level, where the launch site is low-Earth orbit. I wonder how fast that could get you to Mars?

Why drag all those massive engines when for a deep space craft you really only need one, although the 3 (and 3 SL) on Starship allows for redundancy in case of a failure.

[mikegarrison]

4 hours ago, tater said:

I'm less worried about penetration of the surface than I am about Raptors digging a hole.

Raptors that dig holes are kind of cute, really. https://en.wikipedia.org/wiki/Burrowing_owl

[sevenperforce]

Just read the full Bridenstine interview and this jumped out as hilarious....

Quote

Bridenstine: We are working really hard as an agency to get to a day where when we announce a cost and schedule, we can have credibility. Our contractors have to be as committed to that as we are. 

Uh...if you want SpaceX to be as "credible" about cost and schedule as NASA has been with its internal projects, I think they are well ahead of the game.

[RCgothic]

30 minutes ago, tater said:

Why drag all those massive engines when for a deep space craft you really only need one, although the 3 (and 3 SL) on Starship allows for redundancy in case of a failure.

Gets you into orbit.

It's clearly not ridiculously hard to install/detach raptors, SpX seemed able to do it in a day for Starhopper.

Put a few of SH's SL raptors in starship cargo bays and return to earth...

You could even maybe launch with a couple Vac raptors installed. They're dual-belled, and you don't need as much thrust at launch because you're carrying no payload...

[sevenperforce]

45 minutes ago, Lukaszenko said:

Could Super Heavy make orbit with no usable payload? If so, launch it anyway and you end up with something even better. Subtract the fins and legs, and maybe replace a couple engines with vac variants to optimise.

You can then take the whole RTLS concept to the next level, where the launch site is low-Earth orbit. I wonder how fast that could get you to Mars?

If you are launching vastly larger payloads BLEO -- like, two orders of magnitude larger than anything to date -- then it might make sense to launch a transfer vehicle with 3,300 tonnes of propellant. But at that point, you'd be better off using nukes and hydrogen cracked from the lunar surface.

[tater]

 

 

[Xd the great]

https://youtu.be/wzFQJUzoUvM

Does this mean superheavy will be landing and launching on its legs?

[tater]

14 minutes ago, Xd the great said:

https://youtu.be/wzFQJUzoUvM

Does this mean superheavy will be landing and launching on its legs?

It launches from the launch clamps on the pad.

[Nothalogh]

9 hours ago, sh1pman said:

They'll say that space suit visor is actually a VR screen that shows deceiving images of spherical planet. 

Unless they remove the helmets first...

No worries, they can go without the suit

[Xd the great]

13 minutes ago, Nothalogh said:

No worries, they can go without the suit

"Guys, the world is really ro..."

*Dies

Flat Earthers: NASA SILENCED OUR FRIEND FOR SPEAKING OUT THE TRUTH!

[kerbiloid]

Aren't the Dragon, Falcon, and Starship legs feet aligned to a horizontal plane?

So, who is a real flat-earther here?

***

Say, Soyuz or especially Vostok capsule are round, to roll around a sphere.

Edited October 3, 2019 by kerbiloid

[Guest]

@sevenperforce got a link? 

its a real shame about Bridenstine... when he first started looking into alternative launchers for Artemis I was impressed, he seemed like he was really taking the bull by the horns. But ever since that dumb statement throwing shade ahead of spacex’s presentation I can’t help but see him as a puppet, and it doesn’t seem to match other things I’ve heard about spacex’s work on the commercial crew program. 

@kerbiloid it shouldn’t be too bad tho? The ship from 2001 was only 16.7m diameter and that worked out fine ^_~

Edited October 3, 2019 by Guest

[kerbiloid]

(Just in case, put in a spoiler)

Spoiler

12 minutes ago, Dale Christopher said:

The ship from 2001 was only 16.7m diameter and that worked out fine ^_~

Yes, but it still is designed to land on a flat earth.

upd.
I will not be surprised if ASDS are purposed to land in the Surrounding Ocean.

upd 2.
Correct me if I'm wrong, but Dragon has ~600 m/s onboard (i.e. 2 x 300 m/s) and their early presentations depicted a rocket landing.

LES needs ~300 m/s, orbital operations (mostly deorbit) ~300 m/s, landing ~300 m/s,
Where are 300 m/s more?

You have either LES+land, or orbital+land, but not all three.

So, looks like the Dragon was designed to jump to a sky station hanging above the Flat Earth and stay here, then land.

 

Edited October 3, 2019 by kerbiloid

[zolotiyeruki]

I just had a thought last night. A 9m diameter SS has GOT to have the NRO pricking their ears.

[sevenperforce]

4 hours ago, Dale Christopher said:

@sevenperforce got a link? 

its a real shame about Bridenstine... when he first started looking into alternative launchers for Artemis I was impressed, he seemed like he was really taking the bull by the horns. But ever since that dumb statement throwing shade ahead of spacex’s presentation I can’t help but see him as a puppet, and it doesn’t seem to match other things I’ve heard about spacex’s work on the commercial crew program. 

Yeah here: https://www.theatlantic.com/science/archive/2019/10/elon-musk-jim-bridenstine-starship-commercial-crew/599218/

It's worth noting that in the planned schedule for Artemis, all the "commercial launch" deliveries are represented by single-stick rockets with F9 fairings, as opposed to Atlas-style rockets as in the old renders.

Spoiler

On a related note...

I keep thinking about Musk's commentary on aerospikes. I've been thinking about altitude compensation for Starship (or for a smaller SSTO shuttle), but what about Superheavy? Musk is planning on building cheaper, ungimballed SL Raptors with higher, constant thrust. What if they did something like this?

You could pack in more engines in a ring. Not as heavy. Maximum efficiency all the way up. I think it's a solid solution. Basically Chrysler SERV's big brother.

[Rakaydos]

56 minutes ago, sevenperforce said:

Yeah here: https://www.theatlantic.com/science/archive/2019/10/elon-musk-jim-bridenstine-starship-commercial-crew/599218/

It's worth noting that in the planned schedule for Artemis, all the "commercial launch" deliveries are represented by single-stick rockets with F9 fairings, as opposed to Atlas-style rockets as in the old renders.

  Reveal hidden contents

On a related note...

I keep thinking about Musk's commentary on aerospikes. I've been thinking about altitude compensation for Starship (or for a smaller SSTO shuttle), but what about Superheavy? Musk is planning on building cheaper, ungimballed SL Raptors with higher, constant thrust. What if they did something like this?

You could pack in more engines in a ring. Not as heavy. Maximum efficiency all the way up. I think it's a solid solution. Basically Chrysler SERV's big brother.

If I recall the EDA video right, the problem isn't the nozzle, the problem is the combustion chamber.  Aerospikes simply have a harder time getting the same combustion efficiencies and still feed an aerospike's angled nozzle, without having a combustion chamber hanging off to the side penalizing the thrust-to-area ratio.

[tater]

 

1 hour ago, sevenperforce said:

You could pack in more engines in a ring. Not as heavy. Maximum efficiency all the way up. I think it's a solid solution. Basically Chrysler SERV's big brother.

I tend to agree with Musk that it's an SSTO solution, though. What's the best they'd get on I_sp improvements as a function of altitude when the booster is only going to take them to 2.X km/s? I suppose a decent chunk of the orbital velocity component due to the booster is at higher alt, but that moves the I_sp towards 380 from 330, and I think Musk already said that the vac I_sp of SL Raptor is 350. So it's basically to make a plug engine to buy some fraction of 30s of I_sp for a few tens of seconds, right?

[sh1pman]

Mr. Rogozin comes off as such a killjoy...

 

Edited October 3, 2019 by sh1pman

[Rakaydos]

26 minutes ago, sh1pman said:

Mr. Rogozin comes off as such a killjoy...

 

Yea, I'm not sure I'd take the word of a space agency that's been cruising off the prior successes and designs of the Soviets. 

[sh1pman]

1 minute ago, Rakaydos said:

Yea, I'm not sure I'd take the word of a space agency that's been cruising off the prior successes and designs of the Soviets. 

What’s especially funny is that just a couple of days ago Roscosmos failed to attract any investors for their Starlink competitor project. Maybe they need to make some of this “white noise” themselves...

[Wjolcz]

37 minutes ago, sh1pman said:

Mr. Rogozin comes off as such a killjoy...

So does any other competitor. I bet there were many companies doing the same thing when the first 747 was being built.

7 minutes ago, sh1pman said:

What’s especially funny is that just a couple of days ago Roscosmos failed to attract any investors for their Starlink competitor project. Maybe they need to make some of this “white noise” themselves...

I didn't even know they were planning to do something like this too.

[sh1pman]

1 minute ago, Wjolcz said:

So does any other competitor. I bet there were many companies doing the same thing when the first 747 was being built.

The problem with Rogozin is that he is a 100% politician and not a rocket scientist or engineer. He always refers to his “technical specialists”, who (what a surprise) always reaffirm his conviction that all innovation done by Roscosmos’ foreign competitors is unfeasible and is just a PR stunt for investors. Thus, Roscosmos is never in any danger of losing any market share, and can just continue using old Soviet tech until the end of time.