Grasshopper 744m Test

[Meithan]

I just found this video of a recent test of the SpaceX Grasshopper vertical landing rocket. Amazing!!

[Bobhendly]

That was such a freaky view, it almost looked like a 3D Animation! Quite amazing.. What will be the use of a vertical landing rocket anyways? It cant carry enough to get to orbit.

[Mr Shifty]

What will be the use of a vertical landing rocket anyways? It cant carry enough to get to orbit.

This is a test platform for the planned RTLS (Return To Launch Site) of the Falcon 9's first stage. And in fact, SpaceX tested first stage return with their last launch in late September. The first stage separated from the second stage and payload, then re-lighted to push it back toward the launch site, then re-lighted again to slow its descent before splashing down in the ocean. That attempt didn't work perfectly because the rocket was spinning too quickly after the second re-light and it splashed down hard, but SpaceX thinks it has all the pieces now to successfully return the first stage to a landing pad by the end of 2014. This will allow SpaceX to save both time and money, since they hope to be able to refuel and relaunch a used first stage within 2 weeks, and the construction of the first stage represents about 75% of the total cost of rocket construction.

[Meithan]

That was such a freaky view, it almost looked like a 3D Animation! Quite amazing.. What will be the use of a vertical landing rocket anyways? It cant carry enough to get to orbit.

You're right, it can't. The point of this prototype is that it's practically the first stage of their Falcon 9 rocket. So, the plan is to have the first stage of that rocket come back to the Earth intact after separation and land vertically on its own, so it can be recovered. That would make the first stage (the heavier part) of their Falcon 9 rocket fully reusable, reducing launch costs and preparation time. It's a fantastic idea, and seeing these tests I'd say they're very close to achieving it. Go SpaceX!

Damn, Mr Shifty ninja'd the reply .

[PakledHostage]

I just found this video of a recent test of the SpaceX Grasshopper vertical landing rocket. Amazing!!

I thought I'd add a link to nettcod's October 12th thread about the same video. For posterity... There's some interesting discussion in there.

[Meithan]

Thanks for the link PakledHostage.

I have a question, though. Why don't they simply use parachutes for the final part of the landing (like the Shuttle's SRBs used to do)? Is the rocket too heavy? Maybe landing upright is necessary, and that would be hard on parachutes.

[sal_vager]

I may be wrong but I think it's because SpaceX want to have their flyback booster land at a specific spot, this is hard to do with chutes.

[Idobox]

The ultimate goal is to land on the launchpad after separation. If you use parachutes, you'll fall down somewhere east, in the ocean.

[Faark]

I also remember Elon mentioning in a video that the fuel required isn't much or even not at all heavier than parachutes. Chutes don't land very soft, so you most likely need a splash down into the ocean, and salt water isn't very nice to those things as well.

[Mr Shifty]

The ultimate goal is to land on the launchpad after separation.

Small point, but they're actually going to have a separate landing pad for the booster(s) to come back to -- not the launch pad. At Canaveral, they're looking at sites way out on the eastern tip of the cape. To get FAA approval, they have to be two or three miles from anything habitable. They'll build custom pads there to land and recover the vehicles.

[Meithan]

Ah, I think Faark's comment might be the strong argument here. If it does not imply a large difference in launch mass compared to parachutes, then indeed a propulsive landing might be a better option than the hard water landings, especially considering that the Falcon 9 first stage has several Merlin 1D engines and is thus more complex (read: probably more fragile) than, e.g., Shuttle SRBs (I get from Wikipedia that those things splashed down at around 23 m/s -- definitely not soft!).

[Superluminaut]

Small point, but they're actually going to have a separate landing pad for the booster(s) to come back to -- not the launch pad. At Canaveral, they're looking at sites way out on the eastern tip of the cape. To get FAA approval, they have to be two or three miles from anything habitable. They'll build custom pads there to land and recover the vehicles.

Actually last I heard they are going to have both. A down range pad as you have mentioned has the advantage of allowing fore a heavier payload.

However they also have plans to return at least the first stage to the pad it was launched from. To do this a steeper launch is required, after stage separation the subsequently smaller horizontal velocity vector is reversed, leaving gravity to later reverse the vertical one, and the stage falls back directly from above the launch pad.

Its interesting to note that while the return to launch pad plan requires more change in velocity in terms targeting the landing, the down range landing pad plan requires more change in velocity to reduce aerodynamic heating.

[Superluminaut]

The shuttle SRBs were technically not reusable because they landing in salt water. Refurbishable, like the shuttle itself, would be a better term.

Also on a note of irony, the next gen Russian crew pod was planned to use a powered landing. However as a result of many skeptics, current plans include both, a powered landing and a backup parachute.

[togfox]

I just found this video of a recent test of the SpaceX Grasshopper vertical landing rocket. Amazing!!

Siff they are using the stock research tech tree. I saw landing gear - hax!

[K^2]

Also on a note of irony, the next gen Russian crew pod was planned to use a powered landing. However as a result of many skeptics, current plans include both, a powered landing and a backup parachute.

Feel free to add me to the list of skeptics, but given the record of the Soyuz, backup parachute is probably a very good idea. If I was riding one of these, I'd also insist on manual controls for the descent engine, all of relevant valves, and manual release for the parachute. If the fuel isn't hypergolic, I'd probably want a match, too. I've driven Russian cars, and I just can't imagine trusting something like that falling out of space without having a score of redundant manual backups.

[Superluminaut]

Feel free to add me to the list of skeptics, but given the record of the Soyuz, backup parachute is probably a very good idea. If I was riding one of these, I'd also insist on manual controls for the descent engine, all of relevant valves, and manual release for the parachute. If the fuel isn't hypergolic, I'd probably want a match, too. I've driven Russian cars, and I just can't imagine trusting something like that falling out of space without having a score of redundant manual backups.

I believe in it, its the future, and while it may seems like the distant future that is not entirely true. Its a technology already widely in use when landing probes, even on mars in its atmosphere. We have also used it for manned landings, granted they were on the moon, but its still a big step forward in the technology. The reentry precision control concept has also largely been proven by the space shuttle and its reentry attitude control system. Really at this point its just about who is innovative enough to use it first.

And before opting out of Rosco built, check out Nasas model.

http://youtu.be/JzXcTFfV3Ls

[Mr Shifty]

Feel free to add me to the list of skeptics, but given the record of the Soyuz, backup parachute is probably a very good idea. If I was riding one of these, I'd also insist on manual controls for the descent engine, all of relevant valves, and manual release for the parachute. If the fuel isn't hypergolic, I'd probably want a match, too. I've driven Russian cars, and I just can't imagine trusting something like that falling out of space without having a score of redundant manual backups.

I'd be willing to bet Boris Volynov is pretty glad that the Soyuz has parachutes, even if he is missing a few teeth.

Edited October 21, 2013 by Mr Shifty

[Idobox]

Russian space technology works very well, with no fatalities during spaceflight since 1971. It is a bit crude, and probably not the most fuel efficient, but it gets the job done. Given the records, I'd prefer to fly SOyouz than whatever NASA manages to fund next.

That being said, having parachutes or any form of emergency solution is always a good idea when humans are flying.

[Deddly]

Russian space technology works very well, with no fatalities during spaceflight since 1971.

Correct me if I'm wrong, but isn't that debatable? No recorded fatalities is not the same as no fatalities.

[Kulebron]

I found figures of construction and fuel costs, not a hard source, but some enthusiast forum. They found the fuel cost about $1 per kg and 1 Soyuz rocket about $17M. (Couldn't find what portion it makes.) So it might be worthy to save about $10M in each launch. The question is at which price does this saving come? What payload can it carry and how much useful delta-V can it have?

Also, NASA built custom designs that optimized the hardware a lot (lightweight, high pressure), for that they had to make rovers to carry an upright rocket to the pad. Soviet space program was underfinanced, that's why Soyuz was reused a lot, a bit crude, not the most efficient, but turned out cheap and robust. An empty rocket is supported in 3 points if you watch the launch preparation videos, which was impossible with Saturn or Atlas. And it is debugged pretty well: had only 4 crashes in 1800 flights.

As I read the specs of SpaceX rockets, I see they use the same approach to cost reduction and took it further: only 2 stages, less fuel efficient, but I guess, cheap as well.

[Idobox]

Correct me if I'm wrong, but isn't that debatable? No recorded fatalities is not the same as no fatalities.

Really? you think they could hide rockets exploding when the whole world was monitoring it?

I found figures of construction and fuel costs, not a hard source, but some enthusiast forum. They found the fuel cost about $1 per kg and 1 Soyuz rocket about $17M. (Couldn't find what portion it makes.) So it might be worthy to save about $10M in each launch. The question is at which price does this saving come? What payload can it carry and how much useful delta-V can it have?

The most expensive part of a rocket is the turbopump. By comparison, designing the rest of the rocket is almost easy once you have a working pump. If they can just salvage the pumps, they will save at least half the cost.

[Nibb31]

Correct me if I'm wrong, but isn't that debatable? No recorded fatalities is not the same as no fatalities.

If you're implying that the Evil Soviet Union killed many cosmonauts without letting the West know about it, you're wrong. There is absolutely zero evidence that they kept any space-related incidents secret, and all of the archives have been opened up since the Cold War. The accidents that did occur have been pretty well documented (including the worse of all, the Nedelin Disaster in 1960). All of their launches are accounted for as they were tracked and monitored by Western intelligence agencies. We now know practically everything there is to know about the Soviet space program, including the full biographies of Russian cosmonauts, the accidents that did occur, the ins and outs of the internal politics, the testimonies of the scientists and engineers, and the detailed designs of their rockets and spacecraft.

Edited October 21, 2013 by Nibb31

[SnappingTurtle]

Anyone know what's up with the low-velocity flame jet?

[SargeRho]

Gas Generator exhaust. The Merlin engines use a small gas turbine to drive the fuel turbopumps.

[hugix]

If you're implying that the Evil Soviet Union killed many cosmonauts without letting the West know about it, you're wrong. There is absolutely zero evidence that they kept any space-related incidents secret, and all of the archives have been opened up since the Cold War. The accidents that did occur have been pretty well documented (including the worse of all, the Nedelin Disaster in 1960). All of their launches are accounted for as they were tracked and monitored by Western intelligence agencies. We now know practically everything there is to know about the Soviet space program, including the full biographies of Russian cosmonauts, the accidents that did occur, the ins and outs of the internal politics, the testimonies of the scientists and engineers, and the detailed designs of their rockets and spacecraft.

No fatalities but the Russian space program had a lot of errors. Poisonous gasses leaking into the crew areas. Failure to reach orbit. failure to separate the service modules fromt he descent capsules. And when you read about MIR. It's a small wonder nobody died in that thing. Fire. collisions, power surges...