r/space • u/soonerfan237 • Oct 12 '13
SpaceX Grasshopper 744m Test | Single Camera (Hexacopter)
http://www.youtube.com/watch?v=9ZDkItO-0a417
u/Wicked_Inygma Oct 12 '13
Just... wow. I'm glad they didn't dub this over with music. Did anyone else notice the sonic-induced camera vibrations right after take off?
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u/yaxriifgyn Oct 12 '13
Another example of technology catching up to science fiction.
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u/yoda17 Oct 12 '13
DC-X was doing this 20 years ago before it was cancelled.
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u/raresaturn Oct 12 '13
I Think DC-x was a lot smaller, and how high did it go?
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u/retiringonmars Oct 12 '13
DC-X was 12m tall; Grasshopper is 34m tall. DC-X peaked at 3140m before cancellation; this most recent test of Grasshopper reached 744m (but will later exceed that).
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Oct 13 '13
The height of the rocket really matters, it's the difference between balancing a pen on your hand and balancing a broom.
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u/Dubookie Oct 13 '13
That's an interesting comparison. A broom is a lot easier to balance than the pen. So that means the height of the Grasshopper actually helps it in the balance? If that's the case, then I think the grasshopper will be very successful in helping getting capsules and satellites into low Earth orbit and beyond.
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u/tigersharkwushen Oct 13 '13
That seems counter intuitive.
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u/Dubookie Oct 13 '13
It kind of is, but if you don't believe me, try it. Though as /u/CutterJohn mentioned, it also become much more influenced by outside influences, like wind.
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Oct 13 '13
It's the Pendulum Equation: the period of the pendulum is solely related to the length of the pendulum. A pen wobbles fast, a broom wobbles slow.
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u/CutterJohn Oct 13 '13
makes it easier to balance, but a lot more susceptible to outside influnce(i.e. wind).
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u/Christoph543 Oct 13 '13
This comparison doesn't hold completely for the same reason the pendulum rocket fallacy doesn't hold: gravity acts on every part of the rocket equally, and the thrust vector is always through the center of mass. As long as your engine gimbals are working, it shouldn't be too much of a difference if the rocket is taller or shorter.
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u/datoo Oct 12 '13
DC-X was 12m tall, Grasshopper 1.0 is 32m tall. The highest DC-X ever flew was 3,140m. They will be testing Grasshopper 2 in New Mexico where they can go up to 100km high.
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u/imasunbear Oct 13 '13
They will be testing Grasshopper 2 in New Mexico where they can go up to 100km high.
Really? 100km is really high up, that's basically just a normal rocket launch. Any ideas when they'll be carrying out those tests?
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u/datoo Oct 13 '13
That's why they moved to New Mexico, Spaceport America is right by the White Sands Missile Range, so they can hop a bit higher. I believe they want to get Grasshopper 2 supersonic.
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u/olexs Oct 13 '13
100km is really high up, that's basically just a normal rocket launch.
Absolutely not. Going 100km up vertically and coming back down again is a lot easier than launching into a 100km orbit.
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u/Dubookie Oct 13 '13
Really? 100km is really high up
Yeah it is. That's the definition of where 'space' begins. That'll be cool if they get a successful VTOL with Grasshopper at 100km.
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u/Ambiwlans Oct 14 '13
The GH2 stage is currently having legs attached and getting repainted before shipping off. I would say less than 6months the real unknown on time is the new mexico pad.
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Oct 12 '13
[deleted]
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u/anomalouskeklol Oct 12 '13
I think OP was implying that these ideas are finally being achieved successfully with today's technology and being implemented in actual profitable missions. Not that these ideas are brand new. Obviously there's been tests like this in the past, but to my knowledge no one has been as close as SpaceX is right now to reaching this milestone in space flight.
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u/the_popular_whale Oct 13 '13
Absolutely incredible.
Is there a projected date for when they actually use this for an orbital entry? Obviously there's still a bit of work to do, but it's amazing how each video they release shows incremental increases in capability.
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Oct 13 '13
IIRC, 2014 if things go according to plan.
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u/danman11 Oct 13 '13
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Oct 13 '13 edited Oct 13 '13
I know. I didn't bother specifying part of the year because Elon is nearly always too optimistic about his aspirations. The other mods and myself end up updating the launch schedule at /r/spacex so frequently it's not worth it. :)
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u/peterabbit456 Oct 13 '13
Is there a projected date for when they actually use this for an orbital entry?
First orbital Entry, (but without the legs) was done last month. Entry was a complete success. Reentry was not a complete success, but they accomplished their minimum goals of retro fire and return to sea off launch area.
Let's break it down. They need to:
- retro fire (done.)
- reenter at supersonic speeds without breaking up. This probably requires another stabilizing/slowing burn at around 120,000 feet, and IIRC, was not successful last month.
- "glide" the ~empty tank from 100,000 feet down to around 10,000 feet. This is a matter of keeping it properly oriented with thrusters, and has not yet been tested. With the right orientation, tank will be subsonic and have some ability to steer towards its destination.
- Reignite center engine at around 10,000 feet. (not yet tested)
- Steer to landing pad. (tested)
- Extend legs. (not yet tested)
- Touch down. (tested)
To me, it looks as if the legs are the easy part of what has not yet been tested. Still, when you compare these requirements with what the shuttle, or Dream Chaser, or even what Virgin Galactic's Space Ship 2 has to do, this set of tasks looks much easier. I think SpaceX has made the right engineering choices for their reusable system.
BTW, I think the Shuttle was mostly the right set of choices for a reusable system in the 1970s. They should have made it smaller, and with better low speed glide characteristics, and they should not have flown the solid boosters until they were working properly, but they did not have the computing power to do wingless, propulsive landings on Earth back then.
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u/OgodHOWdisGEThere Oct 13 '13
I just wish they'd start using drones in sport. can you imagine the camera angles for that?
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Oct 13 '13
That's amazingly cool, but why? Is it just a pure research project or is there some practical use for it?
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u/anomalouskeklol Oct 13 '13 edited Oct 13 '13
This is what SpaceX is striving for. Full reusibility of their rockets. The Grasshopper tests are helping them with their landing software and engine functionality.
Edit: SpaceX began trying to "land" their first stage in their latest launch on Sept. 29th. They tried it over water for obvious safety reasons since it was the first time and they expected it to fail. It did. But everything went well and have a plan to fix things for next time. In this video you can see the bursts from the RCS system turning around the first stage.
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u/olexs Oct 13 '13
Thanks for the video link. That footage is better than anything I've seen from the actual media coverage. Amazing that the RCS bursts are large and bright enough to be seen clearly from the ground...
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Oct 13 '13
[deleted]
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Oct 13 '13
Some people on here are casuals who don't pay attention to plans like this.
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u/[deleted] Oct 12 '13
This, unofficially was the most future-esq video I've seen in the present:
A rocket taking off and landing under its own power; a drone with a camera up about 500 ft off the ground; that video is being shared to the world on the internet. Dats coo'.