3 ms·
As a former gymnast, I like the sticking the landing analogy but a human (even on an unstable mat) has far more control over their balance point (we do much of
by smoyer 11y ago
As a former gymnast, I like the sticking the landing analogy but a human (even on an unstable mat) has far more control over their balance point (we do much of our balancing by bending at the waist - if only the rocket had one).
In any case, I agree that this was very close. I've also spent a reasonable amount of time on "big water" and was specifically watching the attitude of the landing deck with respect to the horizon. I didn't see much movement of the barge (but that doesn't mean there wasn't some instantaneous movement that together with the force of landing exceeded the leg's load rating).
The other thing that's struck me is that the SSTO advocates could end up becoming irrelevant. Who's going to argue we need SSTO at all if we can recover and reuse all the stages anyway? Multiple stages will remain dramatically more efficient (Yes - I know we don't get space planes with two hour flight times from New York to Tokyo quite as easily).
Finally ... I just have to say "I LOVE THIS". I remember as a child watching the Apollo missions and, as an engineer, I haven't been this excited about a project for a long time. Isn't this exactly the type of thing we can rally humanity around? Who's going to argue that it's not a great accomplishment?
- rtkwe 11y agoThe Falcon 9 isn't totally reusable not does it plan to be. It still has a non-recoverable second stage so it's not quite to the point of a SSTO.
- smoyer 11y agoAre you sure that there's not a plan to recover the second stage once they've consistently been recovering the first stage? (I'm assuming that would be part of the road-map).
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- CarolineW 11y agoFrom Wikipedia: The project's long-term objectives include returning a launch vehicle first stage to the launch site in minutes and to return a second stage to the launch pad following orbital realignment with the launch site and atmospheric reentry in up to 24 hours. https://en.wikipedia.org/wiki/SpaceX_reusable_launch_system_development_program https://en.wikipedia.org/wiki/SpaceX_reusable_launch_system_... However, from other sources: SpaceX would love to recover the second stage, which they had planned. But it sounds like they have given up on that. http://space.stackexchange.com/questions/7814/what-happens-to-the-falcon-9-second-stage-after-payload-separation http://space.stackexchange.com/questions/7814/what-happens-t... What they are referring to there is a transcript I have been unable to access. It's here: http://shitelonsays.com/transcript/elon-musk-at-mits-aeroastro-centennial-part-1-of-6-2014-10-24 http://shitelonsays.com/transcript/elon-musk-at-mits-aeroast... More discussion about it all here: https://www.quora.com/Could-SpaceX-feasibly-recover-the-second-stage-of-a-rocket-in-addition-to-the-first-stage https://www.quora.com/Could-SpaceX-feasibly-recover-the-seco... https://www.reddit.com/r/spacex/comments/1zg7zm/how_soon_can_we_hope_for_2nd_stage_reuse/ https://www.reddit.com/r/spacex/comments/1zg7zm/how_soon_can... https://www.google.co.uk/search?q=space-X+recovering+second+stage https://www.google.co.uk/search?q=space-X+recovering+second+...
- jbooth 11y agoSeems way harder for way lower returns to recover the second stage. Only 1 engine instead of 9, and you're recovering from orbital velocity which opens up several new cans of worms. Would they need heat shielding? The extra weight there might blow away any cost savings from recovering the engine.
- jadyoyster 11y agoHeat shielding is needed, as well as extra landing engines that work outside of vacuum, since the second stage engine would destroy itself under atmospheric pressure. It's easy to see how quickly you start to get dimishing returns, but it would be cool if they could pull it off.
- avmich 11y agoSome experiments were done in early 2000 with inflatable aerobrake. The concept was shown to work, but experiments weren't a complete success. However this technology I'm sure can be applied to the task of returning the second stage. https://en.wikipedia.org/wiki/Atmospheric_entry#Inflatable_heat_shield_reentry https://en.wikipedia.org/wiki/Atmospheric_entry#Inflatable_h...
- raducu 11y agoOr even more futuristic, plasma parachute/heat shield: http://www.nasa.gov/offices/oct/early_stage_innovation/niac/2012_phase_I_fellows_kirtley.html http://www.nasa.gov/offices/oct/early_stage_innovation/niac/...
- zardo 11y agoIt certainly was at the start. https://youtube.com/watch?v=sSF81yjVbJE https://youtube.com/watch?v=sSF81yjVbJE Apparently they are no longer pursuing stage 2 reuse on the Falcon 9. The next gen superheavy lift rocket, the BFR, is intended to be fully reusable though.
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- lutorm 11y agoA reusable SSTO would be a very difficult project, given that noone's even built an expendable SSTO yet.
- rtkwe 11y agoIf you're going to build an expendable rocket designing it as a SSTO doesn't really make sense. With a single stage you can't shed the extra weight of the engines and rocket that got you out of the atmosphere and have to have engines that work both in atmosphere and in vacuum.
- lutorm 11y agoI agree. I'm just saying it's easier to make an expendable than a reusable one, because you don't have to allocate mass to return systems.
- avmich 11y agoInteresting that modern alt-space community often employs the concept "test a little, fly a little", and consider making reuseable systems easier.
- rtkwe 11y agoWhat I was trying to say is that there are other reasons to not build a single stage to orbit expendable rocket, mostly cost and payload capacity. I agree it'd be easier than a reusable version but if you're not returning the stage it makes way more sense to use the 2+ stage designs that are common today. Being able to shed the weight of the atmospheric stage and switch to a vacuum optimized engine is a big benefit.
- Rhinobird 11y agoI read somewhere, that the new first stage can do SSTO unloaded.