Elon Musk's Grasshopper tops 300m, lands safely Elon Musk's Grasshopper rocket has eclipsed the 80-odd metres it managed in March, achieving a “personal best” of around 325 metres and landing successfully, in spite of wind during the test flight. The thousand-foot-mark is a significant milestone for the ten-storey vertical takeoff, vertical landing rocket (VTVL). Getting …
That name has already been taken and is no longer available.
How about Merkin engine instead?
@Allan George Dyer
" ...the RR Merlin's space-flight capabilities are well known..."
Yes, how about four of them: Picture Link
I remember the fuss about the original story, but that illustration is thoroughly faked. Look at the date on the newspaper, and the general feel of the design. You can find plenty of pics of the real front page with that story--14th August 1988. It seems to go back to a Russian report of March that year, and the named "scientist" has cropped up as the source of other similarly incredible reports over more than 20 years.
"the named "scientist" has cropped up as the source of other similarly incredible reports over more than 20 years."
Herr Professor Doktor Zarkov has been the source of many major revelations over almost 70 years. <http://en.wikipedia.org/wiki/Hans_Zarkov>
<exit, stage right, to the sound of Mercury & May singing 'Flash!">
Possibly their smallest customer in terms of units but (probably) one of their most visible.
You've got to wonder what these new sensors are. Have then gone for higher grade units or have they had to shift their design and use new things. For close range high precision location assisted GPS should be fine, as the approach speeds should be well within the allowed civilian specs. If they're not it's all gone seriously pear shaped.
Thumbs up for excellent work and I'm really looking forward to their Dragon pad abort test sometime in Sept.
That should be spectacular
I'd hope that they wouldn't use GPS, as that'd take away the option of using it on the moon or Mars. Rather, I'd figure they'd use laser rangefinders and a handful of inertial sensors for the necessary precision, and utility in places where we don't have GPS satellites overhead.
"For close range high precision location assisted GPS should be fine, as the approach speeds should be well within the allowed civilian specs."
But don't forget that this is a rocket, and even given the recent talk about loosening the ITAR regs, the rocket still counts as a munition, and there is nothing officially "civilian" about it. If they want to use GPS, they can.
I am curious about what they are using though. Traditional inertial sensors I have come across would have the required accuracy to find the home location, or the required range of acceleration to control attitude, but I haven't worked with one that has both. However, since they control both the rocket design, and the landing location, I would have thought that dead rekoning of some kind would be OK for the location, and then they only need inertials for attitude control.
"I am curious about what they are using though. Traditional inertial sensors I have come across would have the required accuracy to find the home location, or the required range of acceleration to control attitude, but I haven't worked with one that has both. However, since they control both the rocket design, and the landing location, I would have thought that dead rekoning of some kind would be OK for the location, and then they only need inertials for attitude control."
Depends what you mean by "traditional." A specialist writing in the GEC Journal some years ago said no one had designed a new "spinning metal" gyroscope INS since the mid 80s. IIRC a lot of these sensors come from "Crossbow Technologies." Rather ironically the actual core laser gyros are from Russia.
People often underestimate the ability of astro nav systems. Specialized telescopes can work in daylight and triangulate to within 6m. NAA Autonetics developed this for the SR71 to run at M3. Later versions were fitted to the B2 and low speed systems are used for continental drift monitoring.
"The DC-XA reached 3140 metres..."
True. It also reached M3.
However that was a test vehicle. It's aspect ratio was much easier to handle.
The DC-X programme was remarkable for what it achieved on the budget it was given.
DC-XA also demonstrated the use of a composite LH2 tank which worked.
It's tempting to speculate what would have happened if the plug nozzle developed for the AFRL in 1974 by Dr Huang of Rocketdyne had not be seriously damaged and was still available and if the DC-X had been designed to be about 1/2 the weight it was. That might have demonstrated both a full blown plug nozzle at M2 plus and (possibly) close to SSTO in a prototype.
But since ARFL managed to wreck the engine and NASA the DC-XA we'll never know.
<sigh>
The other difference is that the lunar lander was human controlled, hence the creation of the flying bedstead so the astronauts could practice flying it.
SpaceX's grasshopper is completely computer controlled. And there's a lot to bed said about only taking small steps to ensure your valuable hardware comes back in one piece so you can have another go!
The propulsion is steerable, so it can move the bottom end a bit to keep the top end pointing up. Just like balancing a broomstick on your hand - if you get it right then you can stand the broomstick there and move your hand to keep it straight. Until you get it wrong of course. That's what the computer is for.
>...why doesn't it just topple over?
Simple really, effectively the thrust from the engines is cancelling the effect gravity is having on the mass of the vehicle. The cancelling effect leaves the behemoth floating precariously between lighter-than-air, and heavier-than-air...just like a feather it is then pretty simple to let it float gently to the ground (if you're a computer controlling the exact amount of thrust and its direction from the twissly bits at the bottom.)
>...all we've done in 44 years...
Eh, try hundreds of thousands, if not millions...
These 44 years you refer to are but a blink of an eye in the progress of this frankly quite bothersome species you are a member of. And to think that we've come from government controlled domain of space and are getting closer to the privately explored version of the same AFTER AROUND 44 YEARS...
The truth is out there!
"We did this on the moon in 1969.
Elon is nothing, if not a marketard."
I agree that judging by what I have read on the Register his achievements pale into insignificance in comparison with yours but in this case he might be on to something as this is almost precisely what you didn't do on the moon as the Lunar Reconnaissance Orbiter's photos of the discarded descent stages from the Apollo missions show.
Don't understand the bitchiness - if he's doing something useless he won't make any money and you can Nelson Muntz at him to your heart's content then.
I think most of the smoke and fire you see is actually the exhaust of the turbines powering the turbopumps. (If you watch closely you can see 2 plumes of fire parallel to the main engine exhaust) The legs do probably get "a bit warm". But I doubt they'd catch on fire or even heat enough to call them hot (As that would jeopardise their structural integrity)
They're not on fire but it looks to me like at least 2 of the feet are trailing plumes of smoke, it's more obvious on the way down. It's probably all the paint smouldering after being blowtorched by the takeoff.
They could build a raised launch platform with a hole in it for the rocket exhaust (like most rocket platforms are) so the legs don't get fried as badly but it'd cost a lot more than the concrete slab they're using. We might see that used for future larger versions as they would need more powerful rockets and presumably be more inclined to fry the landing gear.
The landing pad doesn't look too healthy either. Concrete's cheap, though.
It seems a bit crazy to me that vertical landing under Earth's gravity and in a thick atmposhere is considered a good idea, compared to a lifting body design that can do a glide landing. All that fuel you need to carry up just to give you a soft landing seems like an incredibly expensive waste.
I assume they've run the numbers on this. Anyone got any ideas about what is wrong with aerodynamic landing on a runway? Do vertical landing rockets really weigh less and cost less than wings?
Not so crazy. You'd need as much if not more fuel to carry the extra weight of the lifting and control surfaces, it would dramatically increase the cost of each launch and it would introduce a lot more potential failure points. This way is cheaper, simpler and I'd wager a lot more reliable.
It's not "just" a soft landing either. Bringing back the early rocket stages for refurbishing and reuse will slash the cost of launches.
Yes, I am aware of the fact that other planets/moons have insufficient atmosphere for an aerodynamic landing, but that isn't particularly interesting... landing on other bodies in the solar system isn't exactly a solved problem, , but it is one that has been done many times in many different ways. The Grasshopper is interesting mostly because it is doing so with a quite a large rocket, in a pretty strong gravitational field.
You'd need as much if not more fuel to carry the extra weight of the lifting and control surfaces, it would dramatically increase the cost of each launch and it would introduce a lot more potential failure points.
That argument could work both ways though. Wings and lifting bodies are potentially very simple devices, with no parts that might be expected to explode in an enormous fireball, and control of gliding and flying bodies in Earth's atmosphere is a well understood science after all... the Grasshopper by contrast is quite novel.
That's why I asked about actual figures. The implication is that cost of this whole Grasshopper project, and the additional cost, weight and engineering complexity per rocket using this technology in future still represents excellent value for money compared to parachute+crunchdown or the production of glidable boosters or indeed the use of WhiteKnight style aircraft first stages. Vertical rocket landing is positively Heath Robinson; where are the savings?
Most of the mass of a rocket is made up of fuel or the propulsion systems. An Atlas V rocket ways over 330 tons but the payload is only about 1.5% to 9% depending on where it is going. So fuel is a critical issue, and gliding down (like a Shuttle) basically uses none at all, where coming down on a pillar of fire is probably going to use almost as much as going up in the first place.
Earth has a decent amount of atmosphere for doing that. However, Mars does not and this looks like a good solution to that problem, assuming you can get all that fuel into orbit somehow.
Coming down under engine uses Mmuch MUCH less fuel than going up. For a number of reasons..(some of these cross over a bit)
1) Rocket has a terminal velocity much lower than it need when going upwards - air drag stops it speeding up too much on the way down.
2) Rocket is much lighter since most of its fuel has already been used on the way up.
3) You only need the rocket at decent throttle for the last few miles or so.
4) You don't need to run the engine(s) at full power for the landing, since you have a much lower speed to shed, and much less mass to decelerate.
"An Atlas V rocket ways over 330 tons but the payload is only about 1.5% to 9% depending on where it is going. "
9%? I don't think so. A rocket whose payload is 3.5% of its GTOW is considered very good.
A vehicle whose entire structure (including the payload) was 9% of GTOW is plausible.
...I assume they've run the numbers on this. Anyone got any ideas about what is wrong with aerodynamic landing on a runway? Do vertical landing rockets really weigh less and cost less than wings?
Actually, there was a fair amount of research done on the concept of a piloted "flyback booster" very early in the Space Shuttle program, but were scrapped for technical and cost reasons.
Here's a couple of early Shuttle flyback booster concepts from the late '60s:
http://www.astronautix.com/graphics/b/bsts70b.jpg ...Sleek, but huge.
http://www.astronautix.com/graphics/s/shutbnar.jpg ...Christ, wotta hog.
Columbia.
Of the 135 Space Shuttle flights, single Buran flight, single BOR-4 flight and at least 3 X-37 flights all of which involved an orbit, re-entry and glide phase, only one had a catastrophic failure on re-entry. That failure, damage to heat shielding, is exactly the same sort of risk that any large re-entry vehicle would face regardless of whether it had wings or not.
Furthermore, the accident was caused during re-entry, not something that the Grasshopper or its immediate descendants are ever likely to be subjected to.
Actually, there was a fair amount of research done on the concept of a piloted "flyback booster" very early in the Space Shuttle program, but were scrapped for technical and cost reasons.
Ahh, that's a bit more like it. I guess I'll have to look into those a little further, but I wonder if technology has marched on sufficiently to deal with the issues they'd encountered then. Modern approaches to rocketry staging are slightly different, too. The Grasshopper design is probably cheaper to scale than building ever bigger winged external fuel tanks though, so that is definitely in its favour.
A little more pondering presents two more possible reasons...
1. asymmetric rocket designs are not your friend. The spaceshuttle was very usual... almost all rocket designs are axisymmetric as it makes all sorts of balancing and steering issues at takeoff vastly simpler.
2. The Grasshopper design can almost be integrated 'for free' into the existing Falcon 9 and Falcon 9 Heavy stacks
From a short-to-medium term point of view, (2) is probably the major benefit. Boosters capable of aerodynamic descent probably want a new rocket design, and that's expensive enough for now that any future cost savings might not look very attractive.
Roll on Lofstrom loops, eh?
"Actually, there was a fair amount of research done on the concept of a piloted "flyback booster" very early in the Space Shuttle program, but were scrapped for technical and cost reasons."
But mostly the $1Bn cost cap courtesy of the OMB under Cap Weinberger.
Only the SRB/ET/Orbiter design (devised by a British engineer IIRC) could get the job done for the budget.
And rest, including the high operating costs and the long turnaround times, are history.
<sigh>
"It seems a bit crazy to me that vertical landing under Earth's gravity and in a thick atmposhere is considered a good idea, compared to a lifting body design that can do a glide landing. All that fuel you need to carry up just to give you a soft landing seems like an incredibly expensive waste."
Perhaps you could remind us of the history of successful lifting body based launch vehicles.
I am aware of the PRIME, ASSET, BOR-4 and MiG 105 payloads only.
Perhaps you could remind us of the history of successful lifting body based launch vehicles.
It is remarkably simliar to the history of successful reuseable launch vehicles capable of controlled vertical landing on Earth.
If you include air-breathing, winged first stages then I'd say that aerodynamic, re-useable launch stages have had a rather better history... WhiteKnight has been the first stage of a couple of suborbital flights, and Orbital Sciences' Lockheed L-1011 has been a part of numerous commercial launches putting payloads in orbit using a Pegasus rocket.
I am aware of the PRIME, ASSET, BOR-4 and MiG 105 payloads only.
The fact that no-one has used primary stages capable of aerodynamic landing has not passed me by, believe it or not. This is why I was asking actual figures or at the very least some research papers. Pointing out that no-one has made such a thing does not even begin to explain why not.
That would be a frickin' big parachute and a lot less likely to land on the black to it left behind (or even in the same state as the black dot...)
While they can easily change the launch schedule to avoid a windy day, once the thing is coming down on a parachute you're not going to be able to say "Too windy to parachute in: scratch that!". The controlled rocket descent has a much wider operating envelope with respect to weather.
However...
With a parachute landing you can have used/dumped all the nasty burny stuff before you come down, so a crash is just bits of metal... With a rocket landing, you still need some fuel in there and a crash is a bit more spectacular :)
Even in dead calm weather parachute landings skid on impact as any motion energy is spent in unpredictable ways upon ground contact. Look at professional skydivers/parachutists, they go all over the place when they land and they are dynamic and can compensate for a lot. A big metal tube is not very flexible and the potential for spectacular 'landings' is huge.
"Bushisms. Here's an index of some of his best from 2000 on:
http://politicalhumor.about.com/library/blbushisms.htm"
Oh f**k me.
Here's the thing us non-Americans could never understand. Pretty much all presidential speeches are written by a team of writers. Modern Presidents do not have to remember anything.
So either his speechwriters wrote this for him and he was happy this catches his true tone of speaking IOW you really did elect Forest Gump, or he can't even read an autocue properly.
Words fail me. And on this basis, him too.
Most of these quotes are when he was speaking off the cuff, not from teleprompter (where it was not perfect either it has to be said). It's interesting to compare him to the current incumbent in that regard: whilst Bush would come up with the occasional malapropism when ad-libbing, he was generally coherent enough to be understood most of the time. Obama can't talk without a prompter for more than a sentence or two without descending into complete nonsense.
The correct measurement is Linguine (2321.4286 in this case)
Well done commentards.
1) Why not wings/lifting body? Lots of information around on why not, but basically, weight. Wings are heavy and difficult to deal with on the way up.
2) lateral transformation. It's an incremental program - pretty sure no-one here learned to run before they could walk.
3) Pointless - use a parachute. AFAIK, No parachute has ever be made that's big enough to support something this large. In addition, the speeds involved are too high for initial deployment speed, so you would need drogues first, probably more than one. So why not just use the engines to slow down (I reckon they may use both). Check out Armadillo aerospace for their shenanigans with parachutes.
4) We DIDN'T do this on the Moon in 69. This is a ten story high rocket that weights a hell of a lot, that need to be controlled in an atmosphere and is fully computer controlled. Exactly different to the lunar module.
5) Use Google. All this stuff and more at your fingertips.
I would add to (1) above that for vertical lift off and horizontal landing there is an additional weight penalty (in excess of the weight of the wings and control machinery) because the structural elements of the rocket must be made resistant against lateral forces as well as the axial ones.
For vertical lift off/vertical landing you only need to reinforce the construction against axial acceleration and all rockets are already designed that way.
I though that SpaceX was doing this to recover the rocket for reuse. If so, then the major challenge is getting a job-done stage 1 rocket to contain enough additional fuel to fly laterally (perhaps many, many miles) and then lower itself from ~30-100 miles in the air.
I am interested, but it really sounds like a lot of reserve fuel (deleted from the payload).
As you can see from the landing, if you put it down somewhere (just a few feet away), whatever you land-on needs to have tremendous fire resiliency.
GOOD GOD. You had best PHONE SPACEX right now before they spend any more money.
On the other hand, I wonder if they have already done all the calculation before spending all those millions on a VTOL rocket? Let's hope so eh!
/Sarcasm
Or, you could just check out Elon Musk talking about exactly this on one of his video presentations on YouTube.
"I though that SpaceX was doing this to recover the rocket for reuse. "
Yes.
"If so, then the major challenge is getting a job-done stage 1 rocket to contain enough additional fuel to fly laterally (perhaps many, many miles) and then lower itself from ~30-100 miles in the air."
Wrong. After separation it continues to coast up and along and the atmosphere continues to thin out. Once it's coasted to a stop it has no preferred direction to go except downward.
But flip it end over end with some short thruster bursts (The stage weighs maybe 6% of what it took off as) so it can kill most of that coast and give it a bit of forward momentum (more thruster bursts) and the stage "falls" in an arc, not a straight line, back to the launch site.
So no you need the fuel for the final few Km only. The smarter you are the lower your errors were and the less fuel you need.
Just to set some scale to this, the external tank for Shuttle, when launched from Florida, landed mostly in the Pacific Ocean (a few landed in the Indian Ocean). F9 clearly runs its first stage for less time, though.
It doesn't take much burn time to get stage1-shutdown to be quite far from the launch site.
As someone already mentioned, NASA were doing this on the moon in the 60s, albeit an a smaller scale and without atmospheric factors. But NASA did it with 40 year old technology including a pocket calculator for a computer, transported absolutely every last bit of kit 250,000 miles to a different 'planet' using the mother-of-all rockets and driven by 3 astronauts who had big, shiny balls of steel.
So, although it is rocket science, its hardly rocket science.
(Did you see what I did there?)
Ordinary launch vehicle take off, dropping stages as it go to orbit.
Stages thrown away.
(planned) Falcon 9 Reusable Launch Vehicle also drop off stages on way to orbit.
But stages return to launch site, mate back together, re-fuel and go up again.
Stages not thrown away. Engines used to go up reused to handle landing. No mass wasted with sillies like parachutes, wings or rotor blades.
Simples. In theory.
But trickies in practice. Earths gravity 6x that of Moon. Winds blow about at random and rocket stage Mr Floppy due to thin walls and high aspect ratio.
Spacex use method "stepwise refinement," try little, study results, try some more.
Spacex almost as clever as Meercat gang.
The plastic paratrooper that I bought out of a gumball machine can make a safe landing with just a parachute, so this is obviously a worthless "innovation"! They could have spent that money on something valuable, like solving world hunger, or curing cancer. What a stupid, useless waste.
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