SciAm: Blue Origin Launches and Lands Rocket for the Third Time.
“SpaceX, however, has not yet reused a Falcon 9 rocket stage ...” Less flash and dash, Blue Origin, yet fulfilling its engineering goals beautifully.
Comments:
A fundamentally trickier problem, he spends a bit more to try to bring it back. But early days yet and the only one actually getting off cheap is the one landing on dirt. He is on-par with the rest of the industry. To my mind this is exactly the time to experiment.
No argument. I simply comment upon engineering intent, engineering success. SpaceX is not as successful, because they have too many variables to deal with.
If you can’t land repeatedly, reliably, on land ... there’s no way it’ll work on a ship. I’m not convinced the system will ever work on a ship, except with dumb luck.
Since airplanes need arresting gear, what about ‘petals’ in the ship’s surface, that extend and guide, not unlike a giant cone that closes in and supports the vertical rocket as it settles?
Too many pronouns - sorry
Did you comment before mine, or after? We have identical timestamps.
I still maintain, he won’t be able to land a quadruped with such a narrow leg configuration. Either he hasn’t enough small attitude adjusters, or he hasn’t the computing power to match x/y/z axes with the pitch and roll of the ship.
Another answer would be a much wider set of legs with big flipping pads on ‘em.
IIRC SpaceX has tried one landing on land, and 3 on boats, and a few where they just tried to get to 0,0 over water. I’m sure that the boat landings are harder, but I don’t think that they’re so much harder that they’re not worth attempting. (or even that the boat was the critical factor. They’ve had two that were clearly not boat issues, one ran out of hydraulic fluid, one leg lock issue)
Keep in mind that they use the boat if there’s no way to bring it back to land in their fuel budget, so using the boat has given them a few more attempts to prove their guidance works well enough to hit where it’s not going to damage much. If they only get 1/4 as many attempts, it’s going to take far longer to dial it in.
I’m going to trust the actual rocket engineers on this one.
An empty rocket is pretty much a heavy bottomed coke can. They’re really light up top once the fuel is gone, and there’s a bug chunk of metal at the bottom in the engines. (Empty mass is 25,000Kg, fuel is ~400,000kg, engines are about 4500kg.)
Well, color me skeptical. I think it’s going to need a tripod redesign at the least for water-landing reliability. Remember - no shield from the wind. That rocket is a huge sail.
I’m not a guidance and controls engineer though I would play one on TV if given a choice.
70% of the planet is water, which coincides with safest locations to do these experiments.
The day will come in the not to distant when we want to bring things back. Right now launch contracts are paying for the experiments, this is the time.
This is an exaggerated situation, but demonstrates the kind of control they require.
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On the other hand, SpaceX is doing orbital launches, (and getting paid for them) not just up to the edge of space and back. It takes a _lot_ more energy to get to orbital speeds, and it’s a lot harder to bring the rocket back under control, because at the time that they’re landing, the engines are far too powerful to come close to hovering.