Elon Musk's new re-usable, hovering rocket ship in first test liftoff SpaceX, the upstart space startup founded and bankrolled by famous internet nerdwealth kingpin Elon Musk, says it has carried out the first test of a new rocket craft which could lead to development of fully reusable spacecraft. The company announced yesterday: On Friday, September 21, SpaceX's Grasshopper vertical takeoff …
Easy mistake to make, It's the same team after all, but it was Pixel that was built in a partnership agreement with Armadillo and flown out of Dallas. Morpheus is was the Nasa JSC's successor. More in the final paragraph here
Does say a lot about SpaceX doing it right first time though.. a skill they seem to be exhibiting a lot.
I'm old enough to remember the series pilot of "Salvage 1", wherein: to get an FAA license for the Vulture, they had to find a classification for it that the FAA had, and "Single Stage Ground To Orbit Rocket" wasn't one of them.
So, they lifted the Vulture off, hovered over the ground for a few seconds, and landed. "Experimental Hovercraft" was an FAA classification, and thus it was licensed.
"art" because I'm pretty much stretching the definition of art to fit here...
Roton was one of the coolest ideas of the '90s private spaceship boom (during the dot com bubble). I think the company was called the Rotary Rocket Company. IIRC, the Roton design had two big rotary features: 1) Giant rotor containing combustion chambers and nozzles at base of rocket, using centrifugal force instead of turbopumps to feed propellants to combustion chambers and 2) for the descent phase, rotors with small rockets at the tips that would extend from the nose and bring the capsule in for a vertical, controlled helicopter-style landing.
Surely the first stage is still going to end up down range maybe 400 miles of where they launch? Because turning something that big and fast around and flying it back to where it came from (now that it's missing the sharp bit on top) is surely not practical?
So is the plan to refuel it and fly it back? It would need at the very least some kind of fairing added on the top to make it aerodynamic enough to fly fast enough to get back. Otherwise you're looking at boat or plane to get it back.
So you still seem to have a similar issue to the shuttle's SRBs - collection and return to base. I recall when the space shuttle came out being told that we'd see flights weekly or whatever, that they could turn each craft around in two weeks, but it never happened.
Skylon or something similar is the only way we're going to see regular manned spaceflight that doesn't cost millions so governments are virtually the only customers.
They've shown a video of a simulated mission where the first stage does turn around and fly back to the launch site so that does seem to be the plan, the drawback is that you lose a lot of payload capacity. The simulation showed something the size of a Falcon 9 first stage launching a Falcon 9 second stage, in practice you'd have to cut the second stage down to around the size of the Falcon 1 second stage.
It's not too hard to turn a stage around at altitude, there's hardly any atmosphere at staging and the engines are shut down at that point anyway. Relight shouldn't be a problem, you don't need or indeed want all nine engines running once you've got rid of the mass of the upper stage and payload. I think the plan is for five engines to slow down and get moving back to the launch site, three for the cruise back and just the one (or two if the centre engine didn't restart for some reason) for the final touch down.
I think the major problem with this approach is that you'll have to fly your rocket stage back through the thicker atmosphere with the large, very light and nearly empty tank pointing forward and the heavy engines, turbopumps and thrust structure at the end. Maintaining enough control over this thing to keep it from tumbling and pointing the heavy bits forward is a challenge. Try to throw a dart with the fins pointing forward to see what happens. This thing will be extremely unstable in atmospheric flight.
But it's good they're trying. Recovering and even soft-landing the first stage could make launches much cheaper. Even more so with the F9 Heavy which will add two more first stages as boosters (and these will burn out much sooner and will be easier to return).
They don't land at the launchpad.
They land at a landing pad located suitably downrange (adjusting for planet rotation, etc).
If they -wer-e to land at the same pad they'd make a full orbit first. Nobody is suggesting any sort of "turning around" which, as you note, is impractical, requires many tonnes of fuel, and just isn't done.
These guys know their rocket science pretty well.
I'm going to have to call for your credentials before I let you keep dissing them like that without more cited science.
"If they -wer-e to land at the same pad they'd make a full orbit first. "
So they're proposing single-stage-to-orbit? If that is the case (and they've solved the fundamental problems of achieving this) then it would surely be worthy of trumpeting in the article as it is far more significant that being able to land vertically. The fact they refer to it being the 'first stage' tends to indicate that there will be a second stage, which itself points to the first stage not being capable of orbiting.
My credentials are as an interested graduate mechanical engineer with more than a passing interest in space. I'm not out to 'diss' them or anyone else. I was genuinely interested in their proposals and the article was rather short on such specifics.
"But maybe the problem is not the concept but rather its execution?"
Correct.
The STS was the best system to keep all of the stakeholders happy *most* of the time after Apollo for the *budget* Tricky Dickie was prepared to let them have (whose profile was completely unlike any *real* large scale aerospace project).
BTW That group *never* included US citizens who might have actually wanted to *go* into space.
The purpose of Grasshopper is to work out *how* part of the reusablility profile will be flown.
People have noted that DC-X had a squatter profile which has been what is reckoned to be needed for an SSTO (makes for a *stiffer* structure) but that does not work well for a TSTO and it's a question of making what works as an expendable TSTO work as a reusable *without* needing different stress paths (EG sticking an asymmetrical rotor on the side, as proposed in the late 1960s for the S1c), huge strengthening or *complete* restructuring.
*no* one has tried to land a vehicle with *this* extreme an aspect ratio before (apart from the opening titles to Josey & the Pussycats in Outer Space, for those of a certain age).. However due to F9's *very* good mass ratio they only *need* a single engine to test it, which is handy if it all goes (literally) sideways and they have to build another.
BTW DC-X's purpose was to show fast turnaround of LO2/LH2 engines and (if possible) go from vertical to horizontal and back. Prior to this turnaround of the RL-10s were believed to need *total* strip down. DC-X *proved* turnaround of 4 engines in 26 hours. It failed when some person forgot to hook up the hydraulic line to extend one of the landing legs. The tanks ruptured but the engines were left more or less intact. But they ran out of money and (frankly) NASA did not want something (no matter *how* small) competing with what became the massive clusterf**k that became the X-33.
You shouldn't forget though that DC-X was in no way a spacecraft. This thing was a demonstrator for some things (vertical landing and rapid turnaround) and launching to space was not among these, not by far. You can go rather cheap and quick if all you want to do ever is going up a few hundred feet and landing again.
X-33 instead was planned as a (sub-)orbital fully reusable single-stage spaceplane. Totally different thing, really.
You shouldn't forget though that DC-X was in no way a spacecraft. This thing was a demonstrator for some things (vertical landing and rapid turnaround) and launching to space was not among these, not by far.
True.
"You can go rather cheap and quick if all you want to do ever is going up a few hundred feet and landing again."
I think that's a bit low. IIRC it hit M3 (far from sub orbital but impressive for an all composite aeroshell) and 10s of 1000s of feet altitude.
You're correct that DC-Y would have been the *fully* orbital version (possibly with zero payload but in the ball park) with DC-1 as the first *operational* SSTO vehicle in the series.
"IIRC it hit M3 (far from sub orbital but impressive for an all composite aeroshell) and 10s of 1000s of feet altitude."
3,140 meters (about 1000 feet) altitude with 142 seconds of flight time was the record flight. This is basically nothing, this thing was a demo for vertical landing and nothing else. There's a lot of nostalgia going on with that thing. It surely was a nice project, but far, far away from a spacecraft.
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