totm nov 2023 SpaceX Discussion Thread

[kerbiloid]

A low-precision landing pit with the clamps to catch and the diaphragm hatch.

Spoiler

Land, slide, get catched caught, get hatched.

 

Edited December 31, 2020 by kerbiloid

[cubinator]

I'm thinking something like this would be most structurally stable. I don't think I've ever seen a piston that big, so you might have it actually move with cables, but you can still provide the normal force against the ground like this.

[JoeSchmuckatelli]

28 minutes ago, cubinator said:

I'm thinking something like this would be most structurally stable. I don't think I've ever seen a piston that big, so you might have it actually move with cables, but you can still provide the normal force against the ground like this.

Why not just use a hinged tower like Electron uses at launch?  Keep your pistons - but hinge the bottom of the legs and have the two sides come together to catch each other and support the fins.

[CatastrophicFailure]

2 hours ago, cubinator said:

I'm thinking something like this would be most structurally stable. I don't think I've ever seen a piston that big, so you might have it actually move with cables, but you can still provide the normal force against the ground like this.

I wonder if it could really be just this simple. We keep comparing Superheavy to F9, but it can do one thing F9 cannot, which makes all the difference: hover. That’s going to allow incredible accuracy, no need for complex moving booster-grabbers (the best part is no part), just a great big shock absorber. Thinking that further, SpaceX already uses Tesla technology, they could conceivably borrow from the latter’s guidance and machine learning systems and land the SH visually, using cameras (among other sensors). If the algorithm can keep a Model X between the lines, threading a needle with a Superheavy should be comparatively easy, they could even cover the launch/landing stand with high-contrast markers, kinda like motion-capture rigs, no need to adapt the system to existing roadways, after all. Now, say, combine that with Starship hot-gas thrusters for translation control without gimballing and tilting the booster, then a setup like what @cubinator and @RealKerbal3x mentioned above seems pretty plausible. Might even be able to be retrofitted to the existing launch structure in Boca. 

[RealKerbal3x]

2 minutes ago, CatastrophicFailure said:

I wonder if it could really be just this simple. We keep comparing Superheavy to F9, but it can do one thing F9 cannot, which makes all the difference: hover. That’s going to allow incredible accuracy, no need for complex moving booster-grabbers (the best part is no part), just a great big shock absorber. Thinking that further, SpaceX already uses Tesla technology, they could conceivably borrow from the latter’s guidance and machine learning systems and land the SH visually, using cameras (among other sensors). If the algorithm can keep a Model X between the lines, threading a needle with a Superheavy should be comparatively easy, they could even cover the launch/landing stand with high-contrast markers, kinda like motion-capture rigs, no need to adapt the system to existing roadways, after all. Now, say, combine that with Starship hot-gas thrusters for translation control without gimballing and tilting the booster, then a setup like what @cubinator and @RealKerbal3x mentioned above seems pretty plausible. Might even be able to be retrofitted to the existing launch structure in Boca. 

I think @cubinator's idea would have the best structural stability but unless I'm misinterpreting the scale of his diagram I doubt there's enough space around the launch structure currently under construction for it to fit. And now that I think of it, two retractable arms that can swing into place around the booster (like those on the F9 and Electron strongbacks) is better than the ring design I suggested as Super Heavy doesn't have to 'thread the needle', so to speak.

[cubinator]

4 minutes ago, RealKerbal3x said:

I think @cubinator's idea would have the best structural stability but unless I'm misinterpreting the scale of his diagram I doubt there's enough space around the launch structure currently under construction for it to fit. And now that I think of it, two retractable arms that can swing into place around the booster (like those on the F9 and Electron strongbacks) is better than the ring design I suggested as Super Heavy doesn't have to 'thread the needle', so to speak.

Scale of the supports is slightly exaggerated. There could be three or four of them if needed, which would translate and lower the rocket onto the launch clamps after the landing.

[Geonovast]

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[CatastrophicFailure]

25 minutes ago, RealKerbal3x said:

I think @cubinator's idea would have the best structural stability but unless I'm misinterpreting the scale of his diagram I doubt there's enough space around the launch structure currently under construction for it to fit. And now that I think of it, two retractable arms that can swing into place around the booster (like those on the F9 and Electron strongbacks) is better than the ring design I suggested as Super Heavy doesn't have to 'thread the needle', so to speak.

So, the question is, which is mechanically and engineeringly easier and more reliable? Threading the needle or giant booster huggers?  The actual answer will probably surprise, or be Option C... just a few years ago no one would have suspected a stainless steel rocket built in a field, either. 

[RealKerbal3x]

1 minute ago, CatastrophicFailure said:

So, the question is, which is mechanically and engineeringly easier and more reliable? Threading the needle or giant booster huggers?  The actual answer will probably surprise, or be Option C... just a few years ago no one would have suspected a stainless steel rocket built in a field, either. 

This whole 'catching the booster' thing sounds silly but this is the same company that has done the impossible several times. They'll figure out the best way to do it, and none of us will have predicted it

[mikegarrison]

23 minutes ago, CatastrophicFailure said:

just a few years ago no one would have suspected a stainless steel rocket built in a field, either. 

I'll point out that the idea for steel rockets built like that go back at least as far as the "big dumb boosters" of the 1950s. The idea isn't quite the same, because BDBs were intended to be cheap throwaway designs rather than reusuable high-technology rockets, but I guess I'm just baffled by the people who are impressed with SpaceX welding up rockets in the open air. Ships have been built that way basically forever.

[cubinator]

9 minutes ago, mikegarrison said:

but I guess I'm just baffled by the people who are impressed with SpaceX welding up rockets in the open air. Ships have been built that way basically forever.

Not planetships, until now.

[CatastrophicFailure]

31 minutes ago, mikegarrison said:

I guess I'm just baffled by the people who are impressed with SpaceX welding up rockets in the open air. Ships have been built that way basically forever.

A sort of culture shock, I think. We’re all used to seeing rockets assembled in clean rooms or at least very clean indoor factories, they “seem” such fragile, high-precision things. There is absolutely logic to building a steel rocket not that different from a steel ship, but it’s a mental gear-shift for sure. 

[cubinator]

20 minutes ago, CatastrophicFailure said:

A sort of culture shock, I think. We’re all used to seeing rockets assembled in clean rooms or at least very clean indoor factories, they “seem” such fragile, high-precision things. There is absolutely logic to building a steel rocket not that different from a steel ship, but it’s a mental gear-shift for sure. 

We're also used to orange rockets that are assembled **very** slowly.

[magnemoe]

1 hour ago, RealKerbal3x said:

This whole 'catching the booster' thing sounds silly but this is the same company that has done the impossible several times. They'll figure out the best way to do it, and none of us will have predicted it

I still call it stupid because its over complicated over landing on the launch clamps who Musk previously talked about.
Now I would rater land on an movable stand away from the pad. That also saves the weight of the legs. 
You land on the most sturdy part of the rocket, the part who has to support thousands of tons. accuracy requirements is the same or lower, you could have some guiding spikes allowing for an 10-20 cm error. 
You can come in a bit tilted because of wind or last minute adjustment,  no issue if top is 1-2 meter out. Option to to move this along the drive direction and even offset or even rotate the landing pad. 
After landing drive it to pad to get lifted onto it. 

Now I say this too is over complex over legs but something who is pretty easy to design. 

[RealKerbal3x]

15 hours ago, magnemoe said:

I still call it stupid because its over complicated over landing on the launch clamps who Musk previously talked about.
Now I would rater land on an movable stand away from the pad. That also saves the weight of the legs. 
You land on the most sturdy part of the rocket, the part who has to support thousands of tons. accuracy requirements is the same or lower, you could have some guiding spikes allowing for an 10-20 cm error. 
You can come in a bit tilted because of wind or last minute adjustment,  no issue if top is 1-2 meter out. Option to to move this along the drive direction and even offset or even rotate the landing pad. 
After landing drive it to pad to get lifted onto it. 

Now I say this too is over complex over legs but something who is pretty easy to design. 

It seems a lot less complicated than landing on the launch mount to me. They don't need to have a precision of millimetres with this method, if they design it right they should be able to land within a few metres and still reach the target. And the grid fins are already extremely toughly mounted as the 200t booster is literally hanging from them during its 5g reentry, so beefing them up a little more to take the load of the almost empty vehicle is going to be more mass-efficient than adding dedicated legs.

And SpaceX (well, maybe just Elon) wants Super Heavy to be able to fly again an hour after launch, making landing on a separate structure - even if it's movable - out of the question.

(also, congrats on 10,000 posts )

Edited January 1, 2021 by RealKerbal3x

[RealKerbal3x]

Video on the full process of F9 recovery:

 

[magnemoe]

30 minutes ago, RealKerbal3x said:

It seems a lot less complicated than landing on the launch mount to me. They don't need to have a precision of millimetres with this method, if they design it right they should be able to land within a few metres and still reach the target. And the grid fins are already extremely toughly mounted as the 200t booster is literally hanging from them during its 5g reentry, so beefing them up a little more to take the load of the almost empty vehicle is going to be more mass-efficient than adding dedicated legs.

And SpaceX (well, maybe just Elon) wants Super Heavy to be able to fly again an hour after launch, making landing on a separate structure - even if it's movable - out of the question.

(also, congrats on 10,000 posts )

The fins is mostly there for steering,  yes they add drag its how they work after all but the high g force is from the rocket engines at the bottom.
Had not thought about grabbing the fins. Well first of the shock will be stronger than just hanging them from the fins and they don't do that lifting falcon 9 first stage either. 
On the other hand it might work however I think you need to beef them up so much legs are lighter. 

[RealKerbal3x]

Just now, magnemoe said:

The fins is mostly there for steering,  yes they add drag its how they work after all but the high g force is from the rocket engines at the bottom.
Had not thought about grabbing the fins. Well first of the shock will be stronger than just hanging them from the fins and they don't do that lifting falcon 9 first stage either. 
On the other hand it might work however I think you need to beef them up so much legs are lighter. 

Elon said they were going to grab the booster with the fins, it's not my idea:

 

[kerbiloid]

So, back to the trampoline.

[magnemoe]

11 minutes ago, kerbiloid said:

So, back to the trampoline.

Who makes a bit sense, main issue with catching an capsule if if you miss and hit the boat, this will be much worse than hitting the water. 
That is acceptable for fairings as they are just saved money, they are also huge and lightweight so will not hurt the boat much. 
For an manned capsule it changes. 

And Elron has said some weird stuff like 

Or having cold gas trusters on the upcoming tesla roadster, have fun making the later certified for road use and its an so tiny marked, lets Koenigsegg have it as the spaceX upgrade.
As for robot catgirls, doable as something like an robot waiter there this makes sense, an anime character as its cute but not too human like so trigger uncanny valley.
However Tesla has no experience in humanoid robots.

[kerbiloid]

The robocatgirls will be standing around and catching the landing starship ships by fins.

Did I miss something?

Edited January 1, 2021 by kerbiloid

[NFUN]

On 12/30/2020 at 2:32 PM, magnemoe said:

Grabbing the rocket with the tower, how do you even design this? is it 200 ton super heavy weight? I think he is trolling the no landing on launch clamp crowd. 
Why don't grab it mid air downrange by an flying catgirl. 

WHY NOT INDEED

[kerbiloid]

A powerful soap bubble generator could help very much with starship landing.

By piercing numerous bubbles on its way one by one, the rocket would decrease its speed almost to zero.

Also it would be washed before landing. It saves time for the ground team.

Additionally, it can save some money by Jebson & Jebson product placement, like "With our Rocket shampoo you fly like a rocket!"

Edited January 2, 2021 by kerbiloid

[RealKerbal3x]

Wow, if SN9 lands successfully... 

 

[RCgothic]

SN10 is getting stacked! Nearly ready to go even before SN9's flight!