SpaceX Launches Super-Heavy Communications Satellite
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Landing from a short hop is a much easier operation than from orbit. So far SpaceX have abandoned second stage recovery as too hard.
> Considering trying to bring upper stage back on Falcon Heavy demo flight for full reusability. Odds of success low, but maybe worth a shot.
So they've definitely not abandoned it, and in fact, are actively considering at least as a small possibility again.
The tallest building is about 830m high. A rocket would have to undergo some fierce acceleration to gain any useful speed over that distance. Something like pushing a bullet through water.
The stresses on such a structure, and the launch vehicle, would probably give them a limited life span.
I suspect economics plays a big role here. I suspect it is cheaper to launch multistage rockets than to build a mass driver long / tall enough to be useful.
Theoretical max height for a building using conventional skyscraper techniques is 11 miles, at which point it's ridiculously expensive. Someone at JPL did a work up of using columns made out of ultra pressurized boron balloon tanks, and found that 100km is actually possible, though also ridiculously expensive.
A rocket would have to undergo some fierce acceleration to gain any useful speed over that distance.
To convert a Falcon 1st stage into a cheat-SSTO, all you need to do is to lighten it a bit and give it a bit of a boost. Such is the nasty nature of the rocket equation. You have to accelerate the fuel you need to accelerate the fuel. So by "cheating" with accelerating the fully loaded rocket, you save a lot of fuel weight for the same final delta-v. Due to the same nasty mathematics, this translates to a tiny payload, of course.
I suspect economics plays a big role here. I suspect it is cheaper to launch multistage rockets than to build a mass driver long / tall enough to be useful.
Yadda yadda. Yes, this comes up in just about every discussion like this. It's just neat to think about what else you could do with a Falcon 1st stage. I mean, would you turn down a single stage vehicle you could take into orbit? It would make an extravagant billionaire's toy.
Actually, this general sort of scheme does have a practical use. Modify a methane-oxygen fueled 1st stage so that it could make it to a somewhat higher orbit, but still have payload for a docking and remote maneuvering system. Then have the empty tanks dock with each other to create a space station with tons of internal space. You couldn't do this with the Falcon 9, as it uses RP-1, but methane and oxygen would just boil off into vacuum.
But on-orbit refill: not only has ISS been refueled by numerous vehicles, but China just did it to their new space station. I see people saying it's hard all the time, but no one explaining if this ISS thing is inefficient or something.
I think you saw the same ULA presentation I did, they seemed to think it was very difficult and didn't mention the ISS at all as I recall.
See: https://en.wikipedia.org/wiki/Advanced_Cryogenic_Evolved_Sta...
A single stage would be much larger for the same payload to orbit than a reusable two stage rocket. I doubt it would be cheaper to fly one.
I found it interesting that the latest piece on New Glenn showed the booster landing with winged guide fins. I'm not sure that will work given NASA research into hyper-sonic flight with airfoil wings. If they can pull it off that will be a good data point as well.
At lunch the other day we got into a discussion as to whether a 'landable' booster could also continue on to orbit. Specifically if, after the second stage had separated and headed on, the first stage could re-light and put itself into its own orbit. I couldn't find anywhere that suggested what the mass of the booster was at separation. Would be a fun kerbal program.
https://en.wikipedia.org/wiki/Single-stage-to-orbit#Design_c...
Easy peasy in KSP. No idea if it is possible IRL.
source: also played lots of KSP and looked into why asparagus staging is more difficult IRL
https://www.nasaspaceflight.com/2017/03/spacex-new-spaceflig...
These improvements have been passed on to the Falcon Heavy, and it's expect to put 64,000 kg into LEO, just shy of the SLS's 70,000 kg.
SLS isn't really suitable for defense satellite launches. It's oversized for the job, and won't be capable of the required flight rates (several launches per year at least) for a very long time, if ever. (Current schedule is years between launches.) It also isn't necessary for launching crew to at least low earth orbit; one of the commercial crew contractors (Boeing) is expecting to send crew up on man-rated versions of the ULA Atlas V.
I'd definitely buy a cubesat launch slot for 3k. Perhaps someone should set up a kickstarter or something.
Is the SLS system even worth it anymore? They are using repurposed 1970's shuttle era technology at massively inflated costs. To be fair, no one could have possibly foreseen the quantum leap in rocket technology SpaceX has made over the past 8 years since the SLS was designed. But it's beginning to seem more and more like a government welfare program for Boeing rather than an effective launch system.
Like most things associated with manned space exploration, the tangential benefits of keeping Boeing and USA in operation far outweigh the direct cost and direct benefit.
The guy had a dad who psychologically tortured him, he got thrown down stairs by gangs of blacks in apartheid South Africa, and he completely detached himself from any social connections when he was 17 by moving to Canada. The guy's only reason to live is to fulfill his dreams that he gained from reading every single science fiction book that existed.
Anyway you can think what you want but I know that he's not like the other CEOs that are career CEOs. He's on a mission fueled by intense hardship and retribution
And ULA has a good story about their work on in-space reuse of rockets even if they aren't going to be reusing boosters any time soon.
Even if SpaceX themselves have no interest in going to The Moon, they're not going to say no to a contract to put a Lockheed/ Boeing/ etc NASA funded Moon mission into orbit for them.
So are you saying Musk would just sit back and collect money from Falcon Heavy for the rest of his life? No, he is planning to go to Mars, so SpaceX is going to advance the technology as fast as it can.
Were you really unaware of that? Or perhaps you work for ULA.
Creating methane on a non-Earth body and using that to launch spacecraft would be a different story. ;)
If you want to see the most advanced rocket engine on the planet, look at Arianespace's Vulcain instead. But it can't be used for vertical landings in the current version.
SpaceX Raptor engine, BlueOrigin BE-4, Space Shuttle Main Engine and a number of others are far more impressive then the Vulcain.
Marlin is mostly interesting because of its thrust-to-weight ratio, but there I might agree with you.
That's pretty much the definition of incrementalism.
Yes, there've been a number of watershed transitions, but when you're increasing capability/cost by a factor of ten each decade, that's expected.
As to when it will fly, I expect by the end of the year. They have finally begun static firing actual rocket cores recently, including the heavily redesigned (and another reason for delays) center core.
“Falcon Heavy is one of those things that at first it sounded easy,” Musk said. “We’ll just take two first stages and use them as strap-on boosters. And like, actually no, this is crazy hard, and required a redesign of the center core, and a ton of additional hardware. It was actually shockingly difficult to go from a single core to a triple-core vehicle.”
http://spacenews.com/spacex-to-launch-falcon-heavy-with-two-...
The major reason why Falcon Heavy was delayed for so long is that they were able to make major improvements on the F9. It would not have made much sense to work on a more complicated rocket when there was so much potential in F9.
Falcon Heavy was developed for a pittance compared to the SLS. Even if its delayed another 3 years the SLS would not make a lick of sense.
However, in defense of the SLS 70000kg is the minimum requirement, the rocket will lift more like 80000kg.
Even now it would be cheaper to cancel it. For just the the SLS budget of the next 2 years SpaceX could easily build them the BFR. They could have three different super-heavy boosters from three different companies for the price of the SLS.
> To be fair, no one could have possibly foreseen the quantum leap in rocket technology SpaceX has made over the past 8 years since the SLS was designed.
It was foreseen. They wanted to gather proposals both from inside and outside of NASA because NASA had already realized that it might be much cheaper. They had evaluate how much SpaceX had spend on development and concluded that they would have spent about 10X more.
Non of these investigation were pushed and the SLS 'proposal' was selected. Interestingly another group inside NASA (the only other proposal) want to go back to the F-1 engine.
> But it's beginning to seem more and more like a government welfare program for Boeing rather than an effective launch system.
It was always that. Since its inception everybody called it the Senate Launch System. NASA actually did not want to build it, the Senate forced them and specifically required them to use specific tech. Its nothing but a 20+ Billion pork program.
There is no doubt they could send some pretty large payloads to Mars with the SLS, esp. the later block designs. The question is whether congress is going to commit to the tens of billions to build those designs and actually launch manned missions to other planets or the moon with them.
All of which isn't to say that SLS is cost effective, but it does have capabilities which will be unique for at least a window of time.