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Just amazing to watch. The flip down to gliding just looked so bizarre and futuristic. It's the big WTF I got from first seeing Grasshopper stop and hover in
by jonplackett 6y ago
Just amazing to watch.
The flip down to gliding just looked so bizarre and futuristic.
It's the big WTF I got from first seeing Grasshopper stop and hover in mid air and land again. That's not what rockets are meant to do!
Except of course they are meant to do it!
- jvzr 6y agoI've been following SpaceX for years, and this is exactly my reaction today! Watching the belly flop and the (relatively) slow descent, it felt completely alien, surreal. I'm in utter awe. Congrats to the teams involved, can't wait for SN9 and the rest of Starship!
- fnord77 6y agothe apollo lunar lander did pretty much the same thing.
- galacticaactual 6y agoThe Apollo lunar lander objectively did not belly flop through atmosphere at 1G while having to deal with aerodynamic control surfaces.
- NikolaeVarius 6y agoAre you seriously comparing the Lunar Lander to this? The Lunar Lander was piloted since the computers couldn't do everything, but at the same time a human was good enough at piloting to be able to take over for what the computer couldn't do. This is the result of modern day CFD that that would take humans millions of years to do by hand
- serf 6y ago>This is the result of modern day CFD that that would take humans millions of years to do by hand the package as a whole, yes. belly reorientation for flight has been a thing since the early American arms' race. It's a useful missile trait. Gimbaled vector rockets have existed since the 1940s.[0] Yes, restart is very important -- it's not a requirement for atmospheric belly flight, though. [0]: https://en.wikipedia.org/wiki/RTV-A-2_Hiroc https://en.wikipedia.org/wiki/RTV-A-2_Hiroc
- HPsquared 6y agoNailing the transition to and from belly flight is the hard part, especially so when it's so close to the ground with little margin for error.
- ddalex 6y agoMilitary have been doing the belly flop for years https://www.youtube.com/watch?v=o9vljzfywJI https://www.youtube.com/watch?v=o9vljzfywJI
- Gravityloss 6y agoAlpha Draco was testing body lift in the fifties https://en.wikipedia.org/wiki/Alpha_Draco https://en.wikipedia.org/wiki/Alpha_Draco Robert Brulle has a fascinating memoir https://www.airuniversity.af.edu/Portals/10/AUPress/Books/B_0113_BRULLE_ENGINEERING_SPACE_AGE.pdf https://www.airuniversity.af.edu/Portals/10/AUPress/Books/B_...
- davegauer 6y agoAside: the book Digital Apollo[0] gave me the impression that the computer might well have been able to land, but we'll never know since the astronauts didn't trust it enough to find out. [0] https://mitpress.mit.edu/books/digital-apollo https://mitpress.mit.edu/books/digital-apollo
- sytse 6y agoAnd they had enough confidence that it might work that they attempted to land the first attempt on solid ground instead of in the water.
- jonplackett 6y agoYeah I thought they might do the same kind of 'pretend to land' hover over the water the first time, but no! Maybe because they want to be able to keep it for posterity if it makes it - or launch it again!
- bob33212 6y agoIt is the flight back that they need data for, not landing.
- rst 6y agoNot much different from early work on Falcon 9 landings -- the Grasshopper test rig and F9R-dev-1 prototype both did a bunch of land-to-land hops (the last being the crash that destroyed F9R-dev-1 after an engine failure) before they transitioned to attempted water landings from orbital flights
- oska 6y ago> (the last being the crash that destroyed F9R-dev-1 after an engine failure) From memory I think it blew itself up in the air when something went wrong, rather than crashing.
- mulmen 6y agoThe F9 water landing attempts were just because it was so far downrange though right? Not because a water landing would have been somehow better for the vehicle?
- chasd00 6y agoiirc when spacex asked permission to land a falcon9 on the ground it was a firm "are you crazy? no." So lots of water practice.
- fnord77 6y agothis sort of thing existed before spacex https://www.youtube.com/watch?v=o2sHf-udJI8 https://www.youtube.com/watch?v=o2sHf-udJI8
- mulmen 6y agoIt really didn't though. I'm not aware of any vehicle that does the belly flop flip to vertical landing maneuver, or has even attempted it.
- valuearb 6y agoWhy I love me some DC-X footage, and bemoan what we lost when NASA killed the project for their own boondoggle that failed, talk about missing the point. • 45,000 feet is a lot farther that 450 feet. • Falling and using movable aerodynamic surfaces to descend in reentry position, then rotating into landing position is kind of hard. • Running rocket engines for over four minutes straight is hard, BO has barely run their engines more than 4 minutes total in years of ground tests, without the realism of actual flight and its associated vibrations and accelerations. • Restarting rocket engines is hard. Lastly DC-X cracked up its last landing too.
- seg_lol 6y agoRetractable leg failed to extend and it tipped over when the engines were throttled down. The real issue is why did it have retractable legs in the first place, esp on a test vehicle. Sounds like a great to start writing a post mortem is in the design phase.
- valuearb 6y agoIt was a super cheap program as well. The post mortem should have been let’s build a bigger, better version with a similar budget, but instead NASA killed it to go all in on the 10X+ more expensive X-33 and killed that well before first flight.