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SpaceX Grasshopper Launch Filmed From Drone Helicopter

Soulskill posted 1 year,18 days | from the footage-borrowed-from-FBI dept.

Space 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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Get off the planet! (1)

For a Free Internet (1594621) | 1 year,18 days | (#44203133)

We need more whales and more honeybees and fewer drones and fewer rockets.

Re:Get off the planet! (2)

fritsd (924429) | 1 year,18 days | (#44204649)

Drones are also honeybees... Just sayin'...

Re:Get off the planet! (1)

steak (145650) | 1 year,17 days | (#44210905)

the planet is too prude to get off

a few VTOVL predecessors (4, Informative)

Trepidity (597) | 1 year,18 days | (#44203209)

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.


McDonnell Douglas DC-X []

Japan Space Agency RVT []

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 (1)

tlambert (566799) | 1 year,18 days | (#44203323)

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?

Re:Grasshopper/DC-X design issue (1)

jkflying (2190798) | 1 year,18 days | (#44203359)

Even in a hex losing 2 adjacent struts would cause failure, because the rockets only fire downwards.

Re:Grasshopper/DC-X design issue (1)

tlambert (566799) | 1 year,18 days | (#44204015)

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.

Re:Grasshopper/DC-X design issue (1)

FatLittleMonkey (1341387) | 1 year,18 days | (#44205751)

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.

Re:Grasshopper/DC-X design issue (1)

jkflying (2190798) | 1 year,17 days | (#44207799)

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.

Re: Grasshopper/DC-X design issue (0)

Anonymous Coward | 1 year,17 days | (#44212177)

It is preferable to do everything with extreme accuracy and care rather than trying to overengineering everything to the point that the result is a vehicle too encumbered to work efficiently.

With vehicles relying on airfoils, such as ordinary planes, that approach can be useful. With helicopters and other hovering craft, it becomes more critical. And with rocket-propelled craft, that becomes critical enough that every last ounce of weight needs to be pared away.

Re:a few VTOVL predecessors (1)

ikaruga (2725453) | 1 year,18 days | (#44203361)

I think the technology is interesting but what is the purpose of a VTOL rocket? VTOL aircraft make sense because you can use them for rescue and military operations were a track may not be available. But rockets are just for sending payloads in to orbit. For reusable space craft, unless I see numbers proving me wrong, I think vehicles that use "passive" methods to come back (gliding) like the space shuttle or the Virgin Galactic prototypes seem a lot more economical(dollars/payload weight/launch). Even if the objective is to use VTOL craft for landing on another planet/asteroid/moon and then use the same craft to come back you still need fuel and infrastructure.
Because, at least for me, it's hard to imagine a use, it's hard to get funding as well. I guess the reason SpaceX is spending time and money on these rockets is not because they are actively interested in VTOL vehicles either, but just because they want to benchmark the engines and sensors, so that they can use some of this tech on more useful products.

Re: a few VTOVL predecessors (3, Insightful)

kellymcdonald78 (2654789) | 1 year,18 days | (#44203593)

Spacecraft 2 (Virgin Galatic's production craft) is not an orbital vehicle (not even close). The problem with wings is that except for the last few min of flight, they are dead weight that needs to be carried all the way to orbit and back. The result is a very inefficient vehicle (the Shuttle stack for example was capable of launching about the same payload as the Saturn V, the problem is, most of that payload was taken up by the shuttle itself. When you're dealing with payload margins of a few percent, the difference between using an engine you already need and some lightweight landing legs vs much heavier wings is substantial.

Re: a few VTOVL predecessors (1)

Moofie (22272) | 1 year,18 days | (#44204551)

Don't forget about the landing fuel you have to tote with you along your whole trip. That is not trivial weight.

Re: a few VTOVL predecessors (2)

rossdee (243626) | 1 year,18 days | (#44205293)

"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 (4, Informative)

FatLittleMonkey (1341387) | 1 year,18 days | (#44205819)

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 (3, Informative)

ender06 (913978) | 1 year,18 days | (#44203611)

There is a huge advantage to a VTOL rocket. Obviously the goal here is reusability, but imagine being able to land your rocket back at the very same launch pad it launched from. Do a quick inspection, refuel, launch again. Won't be that simple, but that's the idea. They are actively interested in VTOL, that's the goal of Grasshopper.

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.

Re:a few VTOVL predecessors (1)

gl4ss (559668) | 1 year,17 days | (#44208123)

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)

Re:a few VTOVL predecessors (1)

drinkypoo (153816) | 1 year,17 days | (#44208851)

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.

Re:a few VTOVL predecessors (1)

RespekMyAthorati (798091) | 1 year,17 days | (#44211355)

The Russians would disagree with you. Their landings have always been land-based, from Sputnik to the latest ISS trips.

Re:a few VTOVL predecessors (1)

drinkypoo (153816) | 1 year,17 days | (#44211733)

Sorry, I mean, if you want to save weight with a chute. It takes plenty of chute to land on land.

Re:a few VTOVL predecessors (1)

wagnerrp (1305589) | 1 year,17 days | (#44209233)

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 parachutes, you're still going to be landing at too high a velocity for gear alone to arrest you. You would still need to eject the chute early, to prevent getting tangled in it, and then use rockets to land under power. In the end, you're right back where you were originally, but now with more components that can fail.

On a lifting body, you have to think of the load pattern. A rocket sits vertically, and is powered vertically from the bottom of the stack. The only structural loads it ever sees is vertical compression. If you try to attempt a horizontal landing as a lifting body, your entire craft needs to be redesigned to handle intense bending loads. That's going to eat up a whole lot of weight trying to strengthen it. Far more than you eat up in fuel by just landing vertically, and whatever structural weight you add is just going to eat up more fuel on take off anyway.

Re:a few VTOVL predecessors (1)

ender06 (913978) | 1 year,17 days | (#44209841)

Parachutes don't allow you to perform a precision landing. VTOL rocketry lets you go where you want when you're coming back. You can land in a patch a few square meters in size. Parachutes can only achieve a few hundred square meters accuracy at best.

Re:a few VTOVL predecessors (2)

Sla$hPot (1189603) | 1 year,18 days | (#44203667)

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's is a necessity when you wan't to do interplanetary exploration.

Re:a few VTOVL predecessors (1)

Fjandr (66656) | 1 year,18 days | (#44203901)

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.

Re:a few VTOVL predecessors (1)

cheesybagel (670288) | 1 year,18 days | (#44204135)

Try reading about Ithacus [] . 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.

Re:a few VTOVL predecessors (1)

MichaelSmith (789609) | 1 year,17 days | (#44207469)

SpaceX launchers may recover the first stage by a vertical landing down range.

Re:a few VTOVL predecessors (0)

Anonymous Coward | 1 year,18 days | (#44203551)

its interesting how the 1995's flight ofc the DC-X is much more advanced than spacex's flight.
Not only it turns, changes orientation, goes horizontal, but it also does all this much faster. the landing is quick as it uses only a short burst and I would assume it uses less propellant.

Re:a few VTOVL predecessors (1)

Megane (129182) | 1 year,18 days | (#44203751)

That's because it only uses the regular take-off rockets. There aren't any side thrusters, just a steerable rocket bell. It is designed to do one thing very well, and that is to land unmanned.

Re:a few VTOVL predecessors (1)

Megane (129182) | 1 year,18 days | (#44203799)

Hmm, seems there are in fact small thrusters on the legs, but still nothing like what the DC-X had. (-1)

Anonymous Coward | 1 year,18 days | (#44203213)

It's time for Slashdot to become https-only.

I don't want all my AC posts being sent in the clear. They're not really A then, are they.

Reusable lauching craft (1)

Anonymous Coward | 1 year,18 days | (#44203259)

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.

Re:Reusable lauching craft (2)

Rockoon (1252108) | 1 year,18 days | (#44203297)

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.

Re:Reusable lauching craft (0)

Anonymous Coward | 1 year,18 days | (#44203321)

This is true of aircraft and helicopters as well. There is no reason a rocket can't be launched and then navigated back to its launch site safely. And even if it does fail, the SpaceX rocket first stages are just LOX and RP-1 (basically kerosene). It won't be an environmental disaster.

Re:Reusable lauching craft (1)

Megane (129182) | 1 year,18 days | (#44203779)

Exactly. Aside from the resulting fireball, there isn't really much of a down side if it fails to land properly. It might be smart to land it on a bare pad, though, and not the one that is prepped for launches. It's not like they'll want to re-launch the same one immediately anyhow, because you can't just slap a new second stage on without bringing it back into the assembly building first, at which point you might as well inspect and refurbish it.

Re:Reusable lauching craft (0)

Anonymous Coward | 1 year,18 days | (#44204681)

Ain't nothing that says you can't land it on a barge for purposes of recovery and reuse though. Launching over open oceans is still likely in the plans. These people aren't stupid, so I'm sure they've got it covered.

Re:Reusable lauching craft (1)

wagnerrp (1305589) | 1 year,17 days | (#44209305)

Stability does. There's no way in hell you want to be landing a tall, unstable craft on a pitching barge in rough seas. There's a reason SeaLaunch uses semi-submersible oil platform, where you have a huge amount of mass to keep you stable, and the vast majority of the buoyancy comes from well below the surface chop. Even then, they have to delay launches if the seas are not suitable.

Re:Reusable lauching craft (4, Insightful)

bill_mcgonigle (4333) | 1 year,18 days | (#44204005)

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.

Re:Reusable lauching craft (1)

Jarik C-Bol (894741) | 1 year,18 days | (#44204143)

Rocket engineers motto: "Simplify, and add lightness".

Who cares about the drone (1)

T-Bone-T (1048702) | 1 year,18 days | (#44203263)

That is a strange headline and completely dismisses the accomplishment.

Re:Who cares about the drone (0)

Anonymous Coward | 1 year,18 days | (#44203459)

The link is to a site about drones.

You should know these guys. (1)

Impy the Impiuos Imp (442658) | 1 year,18 days | (#44203269)

"Ok, Astro. Give 'er the gun!"

Space takes time... (2)

taiwanjohn (103839) | 1 year,18 days | (#44203271)

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.

Re:Space takes time... (1)

Cammi (1956130) | 1 year,18 days | (#44203513)

long to develop? Are they reinventing the wheel?

Re:Space takes time... (1)

taiwanjohn (103839) | 1 year,18 days | (#44203577)

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... (3, Insightful)

Jarik C-Bol (894741) | 1 year,18 days | (#44204179)

"If anyone tells you not to re-invent the wheel, ignore them. The first wheel probably fell apart after about 50 feet. Now wheels last for thousands of miles, at incredible are made from space age materials, and are only related to the original wheel in that they are mostly round. Re-invent the wheel all you want." - Some AC years ago.

How does it "navigate"? (1)

Joshua Fan (1733100) | 1 year,18 days | (#44203349)

I don't see any control surfaces or retrothrusters, and rocket engine only has a single nozzle. How does it steer? Maybe an internal gyro?

Re:How does it "navigate"? (1)

jkflying (2190798) | 1 year,18 days | (#44203365)

There are the 4 little stability-only rockets out on the legs.

Re:How does it "navigate"? (0)

Anonymous Coward | 1 year,17 days | (#44208457)

The single Merlin rocket engine on Grasshopper is gimbaled. There is no additional thruster on the legs AFAIK. I don't see what kind of engine they'd use for those anyway (using hydrazine thrusters in this location is a very poor idea).
The smoke that you see at the extremity of the landing strusts is most likely some kind of contrail-like phenomenon caused by the engine exhaust.

Re:How does it "navigate"? (2)

wjcofkc (964165) | 1 year,18 days | (#44203439)

If you look very closely at the video in high-res at full screen, you can clearly see the stability rockets firing at different times in different positions at different intensities as needed to keep the rocket stable. There is a brief moment in the video where the Grasshopper appears to lean ever so slightly at an angle and drift a bit, it's the best point to see the different thrusters firing with different intensities to stabilize it.

I know this is not the first vertical take off and landing rocket tested over the years, but this thing is pretty incredible, and any entity can make it economically and commercially practical, it's SpaceX.

Re:How does it "navigate"? (0)

Anonymous Coward | 1 year,18 days | (#44204421)

The real test will be doing it from a non-vertical starting position. It'll be pretty awesome when they're ready to attempt that.

"Retro" rocket (1)

Anonymous Coward | 1 year,18 days | (#44203609)

Interesting how the Grasshopper works more like the rockets described in early sci-fi than those from NASA

Great video (0)

Anonymous Coward | 1 year,18 days | (#44203621)

Articles like this are why I come to slashdot. Cool technology. Good job mods.

Elon does it again (5, Insightful)

wjcofkc (964165) | 1 year,18 days | (#44203703)

Elon Musk, with his money, and business genius, in combination with overall nerdiness, is bent on dragging us kicking and screaming into the long overdue sci-fi future we have all been been impatiently waiting for and desperately dreaming of. 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. I for one have no problem with this. I believe Elon Musk will take his place among the most important and well recognized figures in history. We should all feel very lucky to have him.

Re:Elon does it again (0)

Anonymous Coward | 1 year,18 days | (#44204383)

Elon Musk is bent on going to Mars. His accomplishments so far have all been towards that goal, starting with "I need money", so he did PayPal. I think he's got a good chance of getting there...

Re:Elon does it again (-1)

Anonymous Coward | 1 year,17 days | (#44206349)

Haven't heard this amount of breathless hype about a Jew huckster since Dean Kamen and the Segway. Musk is just another thieving kike.

Re:Elon does it again (1)

Lincolnshire Poacher (1205798) | 1 year,17 days | (#44207281)

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.

Re:Elon does it again (1)

Anonymous Coward | 1 year,17 days | (#44207315)

Well, aside from doing those things for a tenth of what they cost two decades ago.

Re:Elon does it again (0)

Anonymous Coward | 1 year,17 days | (#44207447)

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.

Accessibility and affordability.

Re:Elon does it again (3, Informative)

Teancum (67324) | 1 year,17 days | (#44207525)

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? (0)

methano (519830) | 1 year,18 days | (#44204607)

What are the chances that maybe the down film is just the up film run backwards? Or vice-versa? Just curious.

Re:Just curious? (1)

mutube (981006) | 1 year,18 days | (#44204729)

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 (1)

wonkey_monkey (2592601) | 1 year,18 days | (#44204837)

So what's the story here? That the test happened, or that it was filmed by a drone? The title suggests it's the latter, but there's not mention of the drone footage in the summary.

Re:Title/summary mismatch (3, Interesting)

Teancum (67324) | 1 year,17 days | (#44207563)

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.

Re:Title/summary mismatch (1)

Festeron (915336) | 1 year,16 days | (#44215897)

This particular test only got to 325 feet

This particular test got to 325 metres, a considerable height greater than 325 feet.

Little or no wind? (1)

RogueWarrior65 (678876) | 1 year,18 days | (#44205861)

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.

Re:Little or no wind? (2)

r2kordmaa (1163933) | 1 year,17 days | (#44207801)

If you look at the video more closely as the grasshopper hovers you can see it leans just enough into wind. There is no such thing as "no wind" at 300m, ever, nowhere in the world.

Re:Little or no wind? (1)

RogueWarrior65 (678876) | 1 year,17 days | (#44209197)

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.

Re:Little or no wind? (1)

r2kordmaa (1163933) | 1 year,17 days | (#44209651)

This is the first stage of a rocket, you can bet it will never lift of from Mars. That is not even the point of it. The point if for the spent rocket stage to come back in one piece and be reusable.

Re:Little or no wind? (1)

Immerman (2627577) | 1 year,17 days | (#44209951)

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) So to translate the wind force into comparable Earth speeds
Wind speed: Martian -- Earth Equivalent (1/167)
Surface: 67.5mph -- 0.4mph
Atmosphere 125mph -- 0.75 mph
Gusts up to: 375mph -- 2.25mph
Which I think makes it clear why we don't see the Rover solar panels getting battered by the wind and can basically ignore it for rocketry purposes: even the ridiculously high-speed gusts have no force behind them. Where the raw speed matters is only in abrasion potential - a grain of windblown sand going 400mph is going to cause the same amount of damage regardless of air pressure.

Re:Little or no wind? (1)

RogueWarrior65 (678876) | 1 year,17 days | (#44212001)

Ah, now it's much clearer. Thanks.

Thats Thuderbird One sorted (1)

Barsteward (969998) | 1 year,17 days | (#44208017)

now lets get Thunderbird Two on is way
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