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SpaceX to develop a fully and rapidly reusable launch system

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October 6, 2011

SpaceX Reusable Launch Vehicle - stage 1 landing on the launch pad

SpaceX Reusable Launch Vehicle - stage 1 landing on the launch pad

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SpaceX, the space transport company that made history by building the world's first private reusable spacecraft, is now embarking on a quest to build the holy grail of space engineering - a reusable launch rocket. Elon Musk, the company's CEO and Chief Technology Officer, announced recently at the National Press Club that computer simulations show their design to be technically feasible. This, Musk seems to suggests, is great news for those who have been considering moving to Mars.

A document issued by the Federal Aviation Administration reveals that the reusable launch vehicle (or RLV) is to be called Grasshopper (at least throughout the testing period). Both stages of the rocket are to be capable of finding their way back to the launch pad and performing a propulsive landing. Based on SpaceX's Falcon 9 rocket, the 106-foot (32 m) tall RLV is to be fitted with a Merlin-1D engine, four steel landing legs and a steel support structure to boot. It is the weight of the additional elements required to make the rocket reusable that poses the biggest technological challenge.

If the Earth's gravity was a little bit higher, the task would be nearly impossible. A slightly lower gravity would make it much easier. However, gravity being what it is, only around 2-3 percent of the lift-off weight is actually carried to orbit. This, Musk explains, leaves very little room for error. So little, in fact, that all the previous attempts at building a fully and rapidly reusable launch system failed to produce as much as a single design that would seem viable on paper. SpaceX already has such a design - now it's time for a reality check.

SpaceX Reusable Launch Vehicle - stage 1 preparation for landing

That the space industry is in desperate need of a RLV is beyond doubt. It becomes even clearer if we look at the numbers. The already mentioned Falcon 9 is the least expensive rocket in the world. It costs around US$50-60 million to launch, and only around $200,000 is down to propellant costs. A reusable rocket would reduce the cost of running a space mission 100-fold.

SpaceX's CEO sees a fully and rapidly reusable space launch system as a necessary development on the way to making life multiplanetary. Musk has expressed his interest in putting man on Mars in multiple interviews, and he considers it to be the long term goal of SpaceX's existence.

While the animation below is not 100 percent accurate, it does provide a pretty good idea of what SpaceX is working on. Musk's full speech to the National Press Club can be seen here.

About the Author
Jan Belezina Formerly in charge of Engadget Poland, Jan Belezina's long time fascination with the advance of new technology has led him to become Gizmag's eyes and ears in Eastern Europe.   All articles by Jan Belezina
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16 Comments

Would it not be possible to use a giant linear electromagnetic motor, powerd buy mega-ultra-extremo capacitors to accelerate the vehicle into space? of course there are limits on how much G force a person can exprience, but surely in combination with a smaller booster rocket, a LEM launch would make the initial launch more efficient and the whole process a lot cheaper?

D-Shift
7th October, 2011 @ 12:03 am PDT

As the strength to weight ratio in structural materials improves all sorts of things once considered impossible have become reality. I remember being told that the Gossamer Albatross's flights were faked because human powered airplanes were impossible.

Slowburn
7th October, 2011 @ 12:41 am PDT

This is an excellent video, but what strikes me, is the amount of extra fuel/weight which is required to return the boosters back to Earth. what happened to parachutes with sea recovery? Also the payload capsule requires retro rockets. I am surprised that this system is feasible.

windykites1
7th October, 2011 @ 04:11 am PDT

Forget the sea recovery , just parachute onto a giant air bag. Do not miss the target.

Stewart Mitchell
7th October, 2011 @ 07:00 am PDT

UP Aerospace has had numerous sub-orbital launches at Spaceport America and recovered the rocket at nearby White Sands Missile Range. Jerry Larsan has proved it all works just fine. Check out the website for the next launch (www.spaceportamerica.com) and (www.up-aerospace.biz).

Tellurider
7th October, 2011 @ 08:32 am PDT

If you read the original articles spaceX speaks of why parachutes to sea recovery are not working. First the vehicles are breaking up before they are low enough for chutes. Second the chutes, deployment system and sea hardening/airbags are adding more weight than the recovery fuel weight would be according their math.

VirtualGathis
7th October, 2011 @ 09:15 am PDT

@D-Shift, No, the air resistance would be fantastic. For the near orbital velocity you would need, the muzzle velocity is around 17 Kilometers per second. But, that still requires a burn at apogee to prevent you from just coming back down very fast for a very hard landing. This has all been studied out very carefully. The sonic boom at the launch end would be fatal of you were closer than a couple of Kilometers from the muzzle.

There was one proposal for it. If the launch mechanism were built in a tube that was evacuated (Pumped down to a vacuum) then you could accelerate up to speed, if then the cap were removed very fast (a modest few hundred Kilo's of C4 should do it), then you could be launched into an extreme orbit. But any such orbit from ground level would then later intersect the ground again. That is why there is a need to have a 'burn' in orbit.

If you increase the mass of the payload to allow for a much larger delta V (Change in velocity), then you can reduce the speed requirement of the catapult. This allows you to fire at a steeper angle, but there is still the little requirement for horizontal acceleration to around 17,000 KM per Hour. In all, it's not a simple solution.

If on the other hand you are on the moon, it's much simpler. There are much easier designs for such catapults to be built on the Moon. No air, and a lessening of the required velocity changes by around 36 times. In fact, if you stage it right, you could launch directly from the Lunar surface to either the L1 or L2 points, or directly to the Earth. The atmosphere makes it extremely hard to do the same from the surface of the earth.

I hope this helps you understand.

YetAnotherBob
7th October, 2011 @ 09:20 am PDT

Cool to see this. My brother and two other guys built the casing for the test version of their stage two rocket. The tests were pretty cool to watch. They're somewhere online.

Christian Lassen
7th October, 2011 @ 10:40 am PDT

@YetAnotherBob- Thank you for you explanation, It was very insightful. I was unaware of the extreme horizontal velocities needed for orbit.

D-Shift
7th October, 2011 @ 12:19 pm PDT

This would be nice if it works, but what is the weight & complexity penalty v.s. the cost of throwaway. Since it is designed to be man-rated, I imagine that the vehicle is designed with considerable margins. The stages will be un-manned on the way back the parts involved in landing (which are beefy enough for takeoff weight) could be held to a lower standard. I imagine that the stages would be somewhat self stabilizing (all the weight is on the bottom) and very light. The descent profile could get it out of the need for a heavy heat shield. I wish him luck. We need more people like Elon.

Doug Halkenhauser
7th October, 2011 @ 01:10 pm PDT

If you read the original articles spaceX speaks of why parachutes to sea recovery are not working. First the vehicles are breaking up before they are low enough for chutes. Second the chutes, deployment system and sea hardening/airbags are adding more weight than the recovery fuel weight would be according their math.

Mahmoodul Haque Qazi
7th October, 2011 @ 04:00 pm PDT

How about instead of a capsule, they use a derivative of the X-37B as the crew vehicle? I'm sure weight makes this idea a non-starter but it might be worth looking at. I'm just not loving the risk to a crew until there has been some serious time logged on it.

Burnzy8
7th October, 2011 @ 07:46 pm PDT

VERY impressed. If they succeed you have a practical reuseable system. Finally! This makes all of a difference between a real Space Age and just middling in between as was the case for the past forty years after Nixon was allowed to junk Saturns. (Shuttle was a fourty years long overpromise/failure/delay.- If Saturn was kept it would have evolved in exactly this dirrection into partially and eventually, perhaps, fully reuseable system.) This reuseable Falcon makes good on the dream of DC-X. Excellent!

nehopsa
9th October, 2011 @ 05:26 am PDT

A space elevator is the answer. No fuss, no muss. Just up & down quickly, cheaply. Once the engineering problem is solved a double scaffold could support two spaces, one for people, one for cargo with rapid accent/decent.

voluntaryist
9th October, 2011 @ 12:40 pm PDT

re; voluntaryist

The orbital tower necessary for a space elevator requires being in space in a big way to build it. Stop apposing the necessary intervening steps.

Slowburn
10th October, 2011 @ 04:26 am PDT

Not a great idea, sounds sort-of ok, but there are too many questions left unanswered.

Firstly, the idea of rocket recovery by sea failed on the whole, i.e. some of the equipment was un-salvageable, and the cost of mounting a sea recovery surpassed the cost of building new rockets anyway. The idea of recoverable rockets then was just a paper-publicity idea to meet a design requirement for a fully re-usable spacecraft. The idea of landing separate rocket stages on the ground autonomously? Laughable at best. How could sufficient fuel payload be stored in each rocket stage for the descent/return flight? Rocket engines are notoriously difficult to throttle, so how could a rocket throttling device be implemented sensitive enough to make minor adjustments during the descent? On days with strong headwind, how does the returning rocket stage "steer" to compensate? Increased heat shielding would need to to implemented for a controlled re-entry, so, more weight. Also, rocket fuel is costly and un-sustainable on the long term, so rockets may not be the best solution moving forward.

Reaction Engines have a much better spacecraft design and a much better engine, plus their design is hydrogen fueled, making it future proof. Their space craft lands on a runway, and has NO rocket booster jettison. Their design has been recognised as feasible, yet they get little funding, which is odd.

http://www.gizmag.com/skylon-spaceplane/19033/

Conor Brannigan
12th October, 2011 @ 08:54 pm PDT
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