SpaceX (general discussion)

Tuna said:
tequilashooter said:
Currently the Raptor 9 engines are expandable not re-usable(AFAIK from a source)
Click to expand...
No, this is not correct. Raptor engines are fully reusable. They have been designed for reuse from the beginning, and should be capable of many more engine starts and require less reconditioning than Merlins.

The only way they are "not reusable", is that on the first launch, SpaceX will not recover either stage, simply because they want to prove that their landing accuracy is suitable before aiming the re-entry track towards something of actual value, by essentially doing a mock landing except just on some specific point of sea. This first launch is obviously going to cost them a lot in engines, and so will not reach their cost targets.
Click to expand...

The design of the Raptor has not been finalized yet. The engines they're installing now are basically already obsolete, which is part of why they won't be reused.
It's entirely possible they aren't focusing on reusability at this stage of the design process: they've shown they're willing to accept interim, 'good enough for now' solutions for these test flights.
 
Hobbes said:
Tuna said:
tequilashooter said:
Currently the Raptor 9 engines are expandable not re-usable(AFAIK from a source)
Click to expand...
No, this is not correct. Raptor engines are fully reusable. They have been designed for reuse from the beginning, and should be capable of many more engine starts and require less reconditioning than Merlins.

The only way they are "not reusable", is that on the first launch, SpaceX will not recover either stage, simply because they want to prove that their landing accuracy is suitable before aiming the re-entry track towards something of actual value, by essentially doing a mock landing except just on some specific point of sea. This first launch is obviously going to cost them a lot in engines, and so will not reach their cost targets.
Click to expand...

The design of the Raptor has not been finalized yet. The engines they're installing now are basically already obsolete, which is part of why they won't be reused.
It's entirely possible they aren't focusing on reusability at this stage of the design process: they've shown they're willing to accept interim, 'good enough for now' solutions for these test flights.
Click to expand...
Full reusability isn't just something you can slap on like a coat of paint.
 
sferrin said:
Hobbes said:
Tuna said:
tequilashooter said:
Currently the Raptor 9 engines are expandable not re-usable(AFAIK from a source)
Click to expand...
No, this is not correct. Raptor engines are fully reusable. They have been designed for reuse from the beginning, and should be capable of many more engine starts and require less reconditioning than Merlins.

The only way they are "not reusable", is that on the first launch, SpaceX will not recover either stage, simply because they want to prove that their landing accuracy is suitable before aiming the re-entry track towards something of actual value, by essentially doing a mock landing except just on some specific point of sea. This first launch is obviously going to cost them a lot in engines, and so will not reach their cost targets.
Click to expand...

The design of the Raptor has not been finalized yet. The engines they're installing now are basically already obsolete, which is part of why they won't be reused.
It's entirely possible they aren't focusing on reusability at this stage of the design process: they've shown they're willing to accept interim, 'good enough for now' solutions for these test flights.
Click to expand...
Full reusability isn't just something you can slap on like a coat of paint.
Click to expand...
I'm not suggesting they haven't thought about reusability, I'm saying the engines they're building now are not fully optimized for reusability yet. Just like they're not at the target thrust yet, for instance. They've got a new version coming soon which massively simplifies the plumbing around the engine.
The videos Everyday Astronaut recently did are worth seeing, it mentions this type of incremental development in several places.
 
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sferrin said:
Does anybody know why they went with many smaller engines vs a couple big ones? Back in the day I recall seeing an engine for something like 24 27 million pounds of thrust. L6H or some such.

L6H

L6H
www.astronautix.com www.astronautix.com
Click to expand...

The same reasons they used 9 engines for Falcon 9.
1. they want to use the same engine for both stages, to reduce development effort. Also 1 production line instead of 2.
2. they want to series-produce engines, smaller engines are easier to handle.
3. Larger engines are more difficult to develop (see the trouble with the F1)
4. It's easier to shut down a few engines than to throttle a really big one to 2% thrust
 
Hobbes said:
sferrin said:
Does anybody know why they went with many smaller engines vs a couple big ones? Back in the day I recall seeing an engine for something like 24 27 million pounds of thrust. L6H or some such.

L6H

L6H
www.astronautix.com www.astronautix.com
Click to expand...

The same reasons they used 9 engines for Falcon 9.
1. they want to use the same engine for both stages, to reduce development effort. Also 1 production line instead of 2.
2. they want to series-produce engines, smaller engines are easier to handle.
3. Larger engines are more difficult to develop (see the trouble with the F1)
4. It's easier to shut down a few engines than to throttle a really big one to 2% thrust
Click to expand...
 
Dumb question, but how is the booster steered? I'm assuming that the engines are fixed, as they are mounted so close together.
Selective thrust variation?

cheers,
Robin.
 
robunos said:
Dumb question, but how is the booster steered? I'm assuming that the engines are fixed, as they are mounted so close together.
Selective thrust variation?

cheers,
Robin.
Click to expand...
the inner are gimbal.
for outer ring who ist fix, spaceX will try in change of thrust of several engines to steer Superheavy

That for moment, can be that Musk as another idea or testing show that the gimbal are sufficient to steer the booster...
 
Thought this was posted already:
science.slashdot.org

SpaceX Is Buying Satellite Data Startup Swarm - Slashdot

SpaceX is acquiring satellite data start-up Swarm Technologies, in a rare deal by Elon Musk's space company that expands the team -- and possibly the technological capabilities -- of its growing Starlink internet service. CNBC reports: Swarm, which has 120 of its tiny SpaceBEE satellites in...
science.slashdot.org
 
@sferrin,@Michel Van, thanks for that . . .
That was my next question . . . will the gimbaled inner engines have enough authority to overcome the fixed outer ones ?

cheers,
Robin.
 
That is probably somewhat to be determined, though presumably SpaceX thinks so or it would have been built differently.
 
Michel Van said:
Interesting detail on third video Tim Dodd

Sam Patel the senior director, starbase operation
label the second Suborbital Pad as Pad D (under preparation for SN20 croy testing)
Click to expand...
He said Pad B; the one where B3 is currently located is likewise Pad A.
robunos said:
That was my next question . . . will the gimbaled inner engines have enough authority to overcome the fixed outer ones ?
Click to expand...
Should be plenty; it's a very long lever arm and in general the booster won't be reaching high angles of attack during ascent. During descent / the landing burn the outer engines aren't used.
 
Dragon029 said:
Michel Van said:
There some rumours
That SpaceX will launching a Satellite to Display Billboard Ads in Space.

I'm not sure but had Capitol Hill not forbid the launch of those sats in 1990s ?

Source
Click to expand...
As the article says it's just a small display with a camera to capture imagery of the ad with the Earth in the background; it won't be visible from the ground (it'd take something like a large cloud / constellation of giant reflectors to create an ad visible from the ground; the ISS is hard enough to spot without deliberately looking for it).
Click to expand...
It's been done.
With EVAs.
By NASA.
In 1984.
 
Last edited:
Dragon029 said:
He said Pad B; the one where B3 is currently located is likewise Pad A.
Click to expand...
i used youtube subtitles what label it Pad D
bad Subtitels, bad, out, out !

robunos said:
That was my next question . . . will the gimbaled inner engines have enough authority to overcome the fixed outer ones ?
Click to expand...
That's 9 Raptors = 2070 metric tons thrust
While 20 Raptors in outer ring = 4600 metric tons thrust
That 1/3 of thrust can be moved, it could work

To compare Saturn I & IB
Here were 8 H-1 engines - 4 were fix and 4 outer engine gimballed

While N1 used reduction on Thrust on parts on 24 engines in outer ring

Starship-Superheavy has a takeoff thrust of 6670 metric Tons
to compare Saturn V = 3579 metric Tons and N1 = 4627 metric tons
Superheavy enter here the territory of NOVA class Rockets !
 
This from Martin Corp Study on Nova rocket in 1962
33193713748_648731ca2a_c.jpg

Texas 2021
E75sYBGXIAAhKnN


source

Ed Dempsey

Explore Ed Dempsey’s 14,743 photos on Flickr!
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Makes me wonder how big of a rocket the Crawlers were designed to handle. Presumably the early Nova was still a possibility when they were being designed.
 
What I heard most from the EA interview w EM was nothing is in stone. Attitude control, heat shields, mass, stage zero - nothing is finalized. They're just building stuff and seeing what fails. That's the gig. Granted, they're rocket scientist's building stuff and seeing what fails - but still...

And all mindshare is on getting to orbit - period.

I love it.

Another cool tidbit was the conversation re welders. Seventy welders onsite, many evidently contractors. That's great for the welders but $$ for SpaceX. Elon wants more SpaceX welders. He wants the speed, he's mindful of cost. I liked how he was on top of this.
 
NeilChapman said:
Another cool tidbit was the conversation re welders. Seventy welders onsite, many evidently contractors. That's great for the welders but $$ for SpaceX. Elon wants more SpaceX welders. He wants the speed, he's mindful of cost. I liked how he was on top of this.
Click to expand...
The problem with that is that certified stainless steel welders are not dime a dozen --- and certified SS welders welding in every position other than welded down-hand (lying flat on the table) are even scarcer ---
 
kitnut617 said:
NeilChapman said:
Another cool tidbit was the conversation re welders. Seventy welders onsite, many evidently contractors. That's great for the welders but $$ for SpaceX. Elon wants more SpaceX welders. He wants the speed, he's mindful of cost. I liked how he was on top of this.
Click to expand...
The problem with that is that certified stainless steel welders are not dime a dozen --- and certified SS welders welding in every position other than welded down-hand (lying flat on the table) are even scarcer ---
Click to expand...
Most of them are probably welding ground equipment together (i.e. not welding stainless). Much of the rocket is resistance welded and automated.
 
Michel Van said:
This from Martin Corp Study on Nova rocket in 1962
33193713748_648731ca2a_c.jpg

Texas 2021
E75sYBGXIAAhKnN


source

Ed Dempsey

Explore Ed Dempsey’s 14,743 photos on Flickr!
www.flickr.com www.flickr.com
Click to expand...
Hope, this picture isn't too 'off-topic"
Project of rough-terrain transporter of N-1 assemblies.

On the serioius note: the multi-wheeled transporters of "Superheavy" seems to be commercial vehicles, made for general cargo haulage, not dedicated to SpaceX exclusively. Another example of "off-the-shelf" technolgy?
 
Silencer1 said:
On the serioius note: the multi-wheeled transporters of "Superheavy" seems to be commercial vehicles, made for general cargo haulage, not dedicated to SpaceX exclusively. Another example of "off-the-shelf" technolgy?
Click to expand...
Yup. Elon absolutely adores repurposing existing equipment and assimilating it into his giant industrial empire.
 
Silencer1 said:
Michel Van said:
This from Martin Corp Study on Nova rocket in 1962
33193713748_648731ca2a_c.jpg

Texas 2021
E75sYBGXIAAhKnN


source

Ed Dempsey

Explore Ed Dempsey’s 14,743 photos on Flickr!
www.flickr.com www.flickr.com
Click to expand...
Hope, this picture isn't too 'off-topic"
Project of rough-terrain transporter of N-1 assemblies.

On the serioius note: the multi-wheeled transporters of "Superheavy" seems to be commercial vehicles, made for general cargo haulage, not dedicated to SpaceX exclusively. Another example of "off-the-shelf" technolgy?
Click to expand...
Self Propelled Modular Transporters. (SPMTs) They use them all over the place:

Part of a Zumwalt:

zumwalt-ddg1000-14.jpg
 
Blue Origin really like to play with fire and get serious Burned

From BO ministry of Propaganda
E8q8ZfzXEAUfECf


What really piss me off are those lies
Launch site that not exist, SpaceX stacks Their Starship/Superheavy on it, to show BO were hammer hangs !
oh BO what about Launch Site with your not existing Rocket New Glenn ?

and 16 flights with 150 tons of propellant = that's 2400 ton CH4/O2 Has Starship such large Tanks ?
i guess BO thinks that HLS bring 150 tons of Payload each time to Moon...

With this on long term BO wasted there credibility and become the unpopular Evil Space Company in World...
 
Bezos is just sounding more and more like a whiny b!tch. Apparently he doesn't react well to competition.
 

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