totm nov 2023 SpaceX Discussion Thread

[tater]

 

 

[tater]

Music

[tater]

 

[Brotoro]

FTransporter 7 booster successfully landed back near launch pad.

[tater]

 

[Brotoro]

 Weird looking 2nd stage nozzle. This is to save money?

[magnemoe]

9 minutes ago, Brotoro said:

 Weird looking 2nd stage nozzle. This is to save money?

Shorter one, might be to save money yes, perhaps using up some first stage engines getting old? 

[RyanRising]

1 hour ago, Brotoro said:

 Weird looking 2nd stage nozzle. This is to save money?

Yeah, that's the reason given. I guess it's less work to make a shorter one? I don't imagine material costs factor in all that much.

[tater]

 

[tater]

 

 

In other news...

 

[tater]

 

[Beccab]

 

[Scotius]

Multi-media presentation during the flight?

[JoeSchmuckatelli]

6 hours ago, Beccab said:

 

That's cool! 

I hope they're doing the high fidelity projection that artists are doing to make buildings dance. 

https://doubletakeprojections.com/services/building-projections/

 

 

[grawl]

4 hours ago, Scotius said:

Multi-media presentation during the flight?

I put a dollar on a pixel-art like live projection of the descent.

** loud space boom boom plays in background **

[mikegarrison]

I guess I missed it when it was reported back in January, but apparently SpaceX has been seeking almost a billion dollars in new capital recently. They also value the company at close to $140B. The stories also said that they raised over $2B in capital last year.

[tater]

 

[AckSed]

I remember the FH test flight and how many holds it had. Trying to temper my excitement is hard.

[JoeSchmuckatelli]

Any ideas on how much of the flight model is 'drone-like' vs 'robot-like'?  (Drone = Remote Control, Robot = Self Control).

I'm guessing that Falcon stages land themselves - but I've never read an article on 'how they do it'.  I mean, I know they can program a whole lot ahead of time, but the ship has to have a certain amount of autonomy given the speeds it travels and need for near-instantaneous adjustments.  Anyone seen published work on this?

[tater]

 

41 minutes ago, JoeSchmuckatelli said:

Any ideas on how much of the flight model is 'drone-like' vs 'robot-like'?  (Drone = Remote Control, Robot = Self Control).

I'm guessing that Falcon stages land themselves - but I've never read an article on 'how they do it'.  I mean, I know they can program a whole lot ahead of time, but the ship has to have a certain amount of autonomy given the speeds it travels and need for near-instantaneous adjustments.  Anyone seen published work on this?

Robot.

[mikegarrison]

Except for things like small quad-copters, drones mostly fly themselves, the same as a lot of airplanes these days. And a lot of the quad-copters can mostly fly themselves too.

1 hour ago, JoeSchmuckatelli said:

I'm guessing that Falcon stages land themselves - but I've never read an article on 'how they do it'.  I mean, I know they can program a whole lot ahead of time, but the ship has to have a certain amount of autonomy given the speeds it travels and need for near-instantaneous adjustments.  Anyone seen published work on this?

I assume they have waypoints they try to steer toward. Or maybe they follow directional radio beams. Or perhaps both.

Edited April 16, 2023 by mikegarrison

[CatastrophicFailure]

3 hours ago, JoeSchmuckatelli said:

Any ideas on how much of the flight model is 'drone-like' vs 'robot-like'?  (Drone = Remote Control, Robot = Self Control).

I'm guessing that Falcon stages land themselves - but I've never read an article on 'how they do it'.  I mean, I know they can program a whole lot ahead of time, but the ship has to have a certain amount of autonomy given the speeds it travels and need for near-instantaneous adjustments.  Anyone seen published work on this?

Not 100% sure on Falcon 9, but usually the first part of the launch, up until like stage sep, is flown “open loop,” the GNC is just flying a pre-programmed “roll this much, pitch this much, pitch a little more” routine. After that it switches to closed loop, where the computer is actively comparing where the rocket IS, to where it IS NOT, and making corrections on the fly. With F9 it might all be the latter now. 
 

Old launchers like the OG Atlas actually were largely “remote controlled,” since they couldn’t fit the needed compute power on board yet. So a loss of signal would (and did) kill the launch. 
 

2 hours ago, mikegarrison said:

assume they have waypoints they try to steer toward. Or maybe they follow directional radio beams. Or perhaps both.

I think it’s all GPS-based, plus a landing radar on the booster. 

[mikegarrison]

9 minutes ago, CatastrophicFailure said:

Not 100% sure on Falcon 9, but usually the first part of the launch, up until like stage sep, is flown “open loop,” the GNC is just flying a pre-programmed “roll this much, pitch this much, pitch a little more” routine. After that it switches to closed loop, where the computer is actively comparing where the rocket IS, to where it IS NOT, and making corrections on the fly. With F9 it might all be the latter now. 
 

Old launchers like the OG Atlas actually were largely “remote controlled,” since they couldn’t fit the needed compute power on board yet. So a loss of signal would (and did) kill the launch. 
 

I think it’s all GPS-based, plus a landing radar on the booster. 

The thing that makes me wonder if they have directional radio is the landing on the barges. Unlike the fixed landing pads, they can't know the exact GPS coordinates for the barge landing pad indefinitely in advance. I guess if they are confident enough that they can control the barge's position between launch and landing, then maybe they could lock in the landing location just before launch.

[RCgothic]

The Falcon booster navigates to pre-set GPS location together with pre-estimated wind conditions. Once it's in the vicinity of the landing zone I believe there's a guidance signal that helps it make the final course corrections, and a landing radar for for judging altitude accurately.

So it's a mix of pre-programmed instructions, dynamic adjustment if engine performance and winds aren't as expected, and terminal guidance.

[tater]