SpaceX Grasshopper Launch Filmed From Drone Helicopter 71
garymortimer writes "SpaceX's Grasshopper flew 325 m (1066 feet) – higher than Manhattan's Chrysler Building – before smoothly landing back on the pad. For the first time in this test, Grasshopper made use of its full navigation sensor suite with the F9-R closed loop control flight algorithms to accomplish a precision landing. Most rockets are equipped with sensors to determine position, but these sensors are generally not accurate enough to accomplish the type of precision landing necessary with Grasshopper."
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the planet is too prude to get off
a few VTOVL predecessors (Score:5, Informative)
If you're interested in this kind of thing, there are a few videos of tests of similar vehicles from the 1990s, in both the U.S. and Japan. But they never got funding to produce production versions.
Links:
McDonnell Douglas DC-X [youtube.com]
Japan Space Agency RVT [youtube.com]
The DC-X still holds the record for the highest flight by a VTOVL rocket, though Space-X plans to challenge that record in a future test.
Grasshopper/DC-X design issue (Score:2)
Grasshopper/DC-X design issue
The failure of the DC-X vehicle resulting in its destruction was the failure of a single hydraulic line not having been connected properly.
Perhaps we could learn from this, and use 6 struts instead of 4 struts in designs like the grasshopper, so that if we lose a strut, or even up to 2 adjacent or 3 non-adjacent struts, the vehicle can still land safely?
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Even in a hex losing 2 adjacent struts would cause failure, because the rockets only fire downwards.
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Even in a hex losing 2 adjacent struts would cause failure, because the rockets only fire downwards.
Yeah, you're right. To allow for loss of adjacent struts, you'd need an octagon so that the CM was still within the bounding area of the surviving struts. I think quadrupling the gear weight would be a problem.
Something to consider might be a vertical column into which a damaged craft could descent and remain (mostly) upright. 5 is barely enough struts to stay within the CM for a single failure; six seems about right.
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Something to consider might be a vertical column into which a damaged craft could descent
And then you've added another whole layer of things to go wrong.
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I think six, with two control systems each running a set of 3 in 60-degree-offset triangles. That way even a control system failure would still result in a recoverable (hopefully) situation.
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Re: a few VTOVL predecessors (Score:3, Insightful)
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Don't forget about the landing fuel you have to tote with you along your whole trip. That is not trivial weight.
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"Don't forget about the landing fuel you have to tote with you along your whole trip. That is not trivial weight."
Which is why a VTOL rocket works better in lower gravity.
It would be useful on a planet with say 1/6th the gravity of earth.
Alternatively maybe we can get Congress to lower the force of gravity. (There is probably more chance that would get passed through the house than say Immigration Reform, gun control, or a balanced budget.)
Re: a few VTOVL predecessors (Score:5, Informative)
Don't forget about the landing fuel you have to tote with you along your whole trip. That is not trivial weight.
Actually it is trivial. The rocket is landing almost empty, the extra fuel to get down is vastly less than the amount to go up.
There were industry studies in the '90s and early 2000s that showed fairly conclusively that the added mass of fuel (especially as rockets are never burned dry) is about the same as all the added mass and complexity from a soft-landing parachute system. (Hard landing parachutes are lighter, but not suitable for a reusable system.) Remember, most of your mass is engines and their controllers, pumps, tanks, etc, which you have to carry anyway. And with first stages (which is what Grasshopper is), you can add more fuel without affecting your payload mass. (Reusable upper stages will eat into payload mass.)
[The extra mass required for a horizontal landing, otoh, massively outweighs the small amount extra fuel required for VTOL. They aren't even in the same universe.]
Re:a few VTOVL predecessors (Score:4, Informative)
The reason this is so much more attractive than a lifting body is that you're taking a lot less extra weight with you every time. The space shuttle was extremely heavy empty, a fair chunk of launch thrust was just launching the shuttle itself, not payloads or the people. So, in short, landing legs and some extra control hardware weigh a lot less than aerobodies and control surfaces. You want to be spending your fuel and thrust on the payload, not the weight of the rocket itself.
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uhm.
if you're willing to ditch most of the mass on the way up there or before coming back down, you can always move a lot more up there with given amount of fuel.
parachutes weigh less.
(I seriously doubt that rocket landing takes less weight than lifting body/chutes)
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If you land with chutes, you pretty much have to splash down. That's fine for returning humans, or ore, and not so fine for most anything else.
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Sorry, I mean, if you want to save weight with a chute. It takes plenty of chute to land on land.
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Drag will get you down to just a few hundred miles per hour all on its own. That last few hundred miles per hour, plus a bit of additional maneuvering fuel, is really a trivial amount of weight in the grand scheme of things. On a half-million pound stack, you're probably looking at maybe ten to twenty thousand pounds more fuel to allow it to land under power. Remember, liquid rocket fuel is cheap. Each half-billion dollar Space Shuttle launch only used a couple million dollars worth of liquid fuel.
With
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VTOL rockets can be used on all planets with an earth like gravity or less, ie. Mars and most moons + asteroids in our solar system.
Gliding is the exception. Only useful on Earth because of the relatively thick atmosphere and it's many landing strips.
DC-X was and still is the way to go, just like the grasshopper is. Hybrids may be useful too.
Projects like Skylon (if it happens) will be a great way to bring astronauts to and from LEO without the inherent single failure issues that comes with VTOL's.
But VTOL'
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Craft using other methods of re-entry and landing do not have the payload capacity of a heavy lift rocket, and heavy lift rockets are incredibly expensive to build.
If the amortized cost of the technology to deploy VTVL rockets does not exceed the cost to build new rockets, it's an economic win and will reduce the cost per pound of putting objects into orbit.
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Try reading about Ithacus [astronautix.com]. Basically you use rocket power to be able to insert troops and cargo anywhere on Earth in a matter of minutes. The idea is hardly new. It dates from the 1960s.
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SpaceX launchers may recover the first stage by a vertical landing down range.
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Reusable lauching craft (Score:1)
This is some of the early testing for a completely reusable rocket first stage. Basically the rocket blasts off, and the second stage separates at some high altitude. The first stage will then fly back home and land. The little Grasshopper test vehicle is the precursor to Falcon 9's first stage that would fly home.
My biggest concern here is that the complexity may be the downfall. Historically, the cost of the increase in complexity of reusable rocket designs outpaced the value of returning the hardware.
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My biggest concern here is that the complexity may be the downfall.
I think the main issue is that bringing things down over anything but ocean can have very negative consequences when a failure occurs.
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Re:Reusable lauching craft (Score:5, Insightful)
My biggest concern here is that the complexity may be the downfall. Historically, the cost of the increase in complexity of reusable rocket designs outpaced the value of returning the hardware.
But then they tried the Shuttle to reduce costs below that of rockets (hey, it looked good on papers with politically dictated calculations). Consider the complexity of *that* solution, especially the make-work landings at Edwards!
SpaceX has no motivation other than to deliver rocketry services to its internal and external customers at the most cost-effective price. It would be extraordinary if they hadn't considered the lifecycle costs.
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Who cares about the drone (Score:2)
That is a strange headline and completely dismisses the accomplishment.
You should know these guys. (Score:1)
"Ok, Astro. Give 'er the gun!"
Space takes time... (Score:3)
I can't wait to see them recover a first stage from an actual launch. Musk has said they might be ready to try it as early as next year. I wish it could be sooner, but space hardware always takes a long time to develop. The dragon capsule is already reusable, though they haven't reused one yet. So if they can reuse the 1st stage too, that could greatly reduce launch costs even before they achieve full reusability. The 2nd stage is probably the cheapest 'segment' of the stack, so it's less urgent to get them fully reusable right away. (I don't know how much the 2nd stage costs, compared to the 1st, but with only one engine instead of nine, it's got to be a huge difference.)
Between this and the upcoming human-rated Dragon with propulsive landing capability, there's a lot of "coolness" in the pipeline for the next few years. And not just from SpaceX... Lots of other "NewSpace" companies are doing cool stuff too, like Masten, XCor, Blue Origin, etc.. It's nice to see so much progress in so many areas.
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In a way, yes... Nobody has ever built a fully reusable rocket yet. Actually, SpaceX is going at a pretty good pace, but it still takes a long time. They have to reach a high degree of certainty that this complex system will work, and will be able to tolerate a few minor glitches along the way.
Re:Space takes time... (Score:4, Insightful)
How does it "navigate"? (Score:2)
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There are the 4 little stability-only rockets out on the legs.
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I know this is not the first vertical take off and landing rocket tes
"Retro" rocket (Score:1)
Interesting how the Grasshopper works more like the rockets described in early sci-fi than those from NASA
Elon does it again (Score:5, Insightful)
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The rapid progress his technology companies are achieving is nothing short of breathtaking. He pushes limits so far, and so hard, that those nearly impossible limits have been powerless to push back
Space-X hasn't achieved one single thing that hadn't already been done by at least two predecessors each, two decades or more ago.
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Well, aside from doing those things for a tenth of what they cost two decades ago.
Re:Elon does it again (Score:4, Informative)
Really? Can you name any organization that has accomplished what SpaceX has done other than people who have the motto "Waste anything but time"?
Yes, in the 1960's that motto was plastered on posters and put in giant letters inside manufacturing plants for building the Apollo rockets that went to the Moon. That was nearly the same philosophy that the Russian space program had at the same time (although admittedly a smaller budget). To date, very few organization have put anything into orbit that wasn't a national government... usually of a very large country that is a permanent member of the UN Security Council. In fact, for manned flight it is only sitting members of that exclusive club and SpaceX might be able to join that elite few very soon.
If you are suggesting that Boeing and Lockheed-Martin (or their predecessor companies) built stuff and sent it into orbit, it sure as heck wasn't on their dime nor were their engineers even the only people building those rockets.
Just curious? (Score:1)
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You're quite right! If you look closely in the second half of the video you can clearly see the smoke is traveling backwards into the engine. I'm surprised nobody else has noticed that yet!
Title/summary mismatch (Score:2)
Re:Title/summary mismatch (Score:4, Interesting)
The video was filmed by a "helicopter drone". Essentially a slightly larger RC helicopter that had a camera mounted underneath.
Actually that helicopter didn't even need to be all that big, considering the miniaturization of cameras. It is stuff that you can literally just purchase over the internet for a relatively modest amount of money. In other words, something a full-time engineer with a little money to burn could easily afford if they cared and have a hobby on the side. That wasn't even really the story here other than the fact it took footage of something else really remarkable.
The advantage of a drone in this case is that a manned helicopter would be prohibited from the range for safety reasons, so the drone was the only way to get something in that camera angle and proximity. SpaceX has several other cameras from many other angles that were taking footage of the launch... all that would be necessary if there was a serious mishap.
As a matter of fact, Elon Musk has started to grumble to his engineers complaining that they haven't destroyed the Grasshopper yet. He doesn't want them to purposely crater the machine, but he does want them to push the envelope a bit as disasters really are a great way to learn about the performance limits of machines like this.
This particular test only got to 325 feet (the highest one so far), but they want to incrementally move higher and higher... eventually going to several thousand feet. Unfortunately for the SpaceX engineers, those tests will need to happen some place other than central Texas as high altitude tests will interfere with aircraft traffic and could crater into Waco, Texas as an outside potential. They are eventually going to move these tests to New Mexico... at least that seems to be the current plan that I've seen and based upon launch permit applications SpaceX has already made to the FAA.
I've heard it suggested that this technology may even be tested in an upcoming Falcon 9 launch, where an attempt to at least slow down and attempt recovery of the first stage after launch will be made.
Little or no wind? (Score:2)
The video seems to suggest almost no wind. I'd like to see this puppy operate in windy conditions where you can't really measure the speed due to the lack of a widespread weather network.
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I'm referring to the little wisps of smoke that emanate from the rocket. Sure they drift slightly indicating a suggestion of wind but nowhere near what has been reported to exist on Mars.
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As r2kordmaa says this particular design is probably not intended to ever see Mars, though if it proves out here some derivative technology is a likely candidate.
As far as wind is concerned - it's not just speed that matters. Martian atmospheric surface pressure is about 0.6% of Earth's, or about 167x less. The net force transmitted by the wind will scale similarly since it is basically a product of the wind speed and the number of molecules impacting a surface (which scales pretty linearly with pressure)
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Ah, now it's much clearer. Thanks.
Thats Thuderbird One sorted (Score:1)