SpaceX Plans to Land Next Falcon 9 on Solid Ground

Post by Tharkun » Fri, Apr 17, 2015, 5:01 AM UTC

Lorento wrote: post #130

anigbrowl wrote: post #111

Earlier quoted context omitted.

Landing is an awful lot harder than taking off, it seems to me; a single engine rocket with stabilizing jets is a bit like trying to land a pogo stick - possible, but inherently problematic. I know this must seem stupidly obvious, but I wonder if a better design for a reusable launch vehicle isn't 4 engines connected by a frame with the payload in the center, basically a chair. Yeah, it sounds horribly unwieldy with…

It's always tempting with difficult control problems to imagine why not just do what feels stable? Why not just hold it in place with something? Why not make it shorter and wider? For an example of why not - compare a turtle to a human. The human is inherintely unstable and its vital organs are exposed through weak flesh. If we lose control of our unstable balance, we die when our head hits the ground. The turtle is…

Post by AYBABTME » Fri, Apr 17, 2015, 6:00 AM UTC

toomuchtodo wrote: post #94

daeken wrote: post #81

Earlier quoted context omitted.

It's refueled in-situ and launched back up with a minimal payload weight. Getting off the surface of Mars back into an orbit with a low weight (basically crew + life support + minimal payload) is pretty straightforward, considering the low gravity and thin atmosphere. From there, you can dock to a much larger tug ship and go back to Earth orbit, refueling on orbit and landing propulsively again.

I didn't spend the time searching google to provide citations, but it is feasible to generate fuel autonomously on the Martian surface and store it for future use. Can we launch a vehicle that will de-orbit, safely land, and then begin processing fuel using nuclear (edit: I removed solar here; solar would not provide enough power for such a facility) for power and the Martian atmosphere and soil as feedstock? Not qui…

Post by mikeash » Fri, Apr 17, 2015, 3:03 PM UTC

elchief wrote: post #123

mikeash wrote: post #93

Earlier quoted context omitted.

The first stage accounts for about 75% of the total cost of the Falcon 9, so best case would be a 75% cost reduction. Any refurbishment needed before flying again would reduce that, as well as whatever fixed costs there are for a launch, like fuel, salaries for on-site workers, consumable launch pad equipment, or whatever. Refurbishment is the big wild card. If the rocket is ready to go again with no work then it cou…

Sweet, thx. That's a pretty big game-changer.

Post by saganus » Fri, Apr 17, 2015, 5:17 PM UTC

noir_lord wrote: post #64

saganus wrote: post #55

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But can't the vehicle carry them to Mars? Kind of like the airbag system for one of the rovers, can't remember which one (Curiosity?) Or even better, how about getting it to land sideways on purpose? I don't see how that would be more difficult than doing it upright.

Imagine the material that a coke can is made off. Now imagine a cylinder made of that material 3-4 times wider than a barrel and 20-30ft high. That's why you can't land them sideways they'd just crush themselves.

Post by flountown » Tue, Apr 21, 2015, 2:19 PM UTC

mbell wrote: post #59

flountown wrote: post #49

Are there any articles or press out there that describe the stabilization tech used on the barge? A lot of the things when looking through Google seem to focus on the challenges of guiding the rocket but not stabilizing the platform. I guess it tends to be a non-issue since it seems their plan all along was landing it on land, but I'd be really interested to see the design story that went into the barge.

There is nothing special about the barge stabilization, it's off the shelf marine tech. A few azimuth thrusters controlled by a station keeping system. The only unusual thing about it is that the azimuth thrusters are a lot more powerful than would normally be put on a barge that size to give it better positional control in rough seas.