Project Dizzy - playing with centrifugal force

[Potterus]

Had a go at trying to replicate the concept from the Mars Direct plan - the manned stage is linked to a spent booster stage by a tether and rotated around a common axis to produce artificial gravity for a crew using centrifugal force.

So I sent Jeb, Bill and Bob into orbit with some new fangled technology from KAS (winch + an attachment point) to give it a whirl. Once orbit had been achieved, the booster stage was separated and after a quick EVA by Jeb to attach the winch to the spent stage. When Jeb was back on board, special laterally mounted engines were fired to spin up this un-godly contraption.

Things were going... okay, apart from it being an uncontrollable mess and I'm sure making the crew very dizzy. The accelerometer said we were getting about 0.1G with the engines off and the spin had got a little bit less violent. But then the winch snapped off and send the boost stage off into the abyss. The maneuver had also degraded the periapsis by from 130km to 60km, so I sent the boys home for some well deserved cake and pie

Here is a little gif of Project Dizzy in action:

[ramnrmeul]

Nice... Do you have an image of the orbit of the debris?

[Potterus]

I kept the save file after the mission, will try to get an image up later from the tracking station

[Potterus]

Here you go

The debris in the circular orbit is the decoupler used to separate the craft before spinning began

[ramnrmeul]

If you could spin it fast enough and release it at the right time, you could send stuff to the Mun! Also, I'm pretty sure that with a long cable, you could grab crafts that will have a close encounter with your ship.

[Cydonian Monk]

I'm pretty sure that with a long cable, you could grab crafts that will have a close encounter with your ship.

One of Charlie Stross' stories had something like that, grabbing suborbital ships on ascent and flinging them into orbit. I've been half tempted to try it, but I'm not sure KSP has the precision to pull it off.

[Potterus]

If you could spin it fast enough and release it at the right time, you could send stuff to the Mun!

I had the same thought. Longer tether and faster spin, you could build enough energy to do this.

Timing it right, keeping it under control so its aimed correctly and getting enough momentum going before the tether snaps would be the tricky parts.

[Kieve]

I had the same thought. Longer tether and faster spin, you could build enough energy to do this.

Timing it right, keeping it under control so its aimed correctly and getting enough momentum going before the tether snaps would be the tricky parts.

This is KSP. Your Kerbals would snap the wrong end of the line and fling themselves right into Kerbin at hypersonic velocity.

Which would be hilarious and entertaining, but somewhat lacking a return on the time investment.

[JTG]

Also, I'm pretty sure that with a long cable, you could grab crafts that will have a close encounter with your ship.

You could probably use this method to throw debris into Kerbin's atmosphere. A new type of debris destroyer!

[Geschosskopf]

Hehehe, yeah, that part of Mars Direct about stretching out the cable and spinning has always struck me as just plausible enough to convince folks to build it, but then will turn out to be a total disaster. I just don't see how they can keep everything from twisting and jerking as astronauts move around.

As to tossing stuff around, there was actually a concept to throw things back and forth between Earth and the Moon. The system consisted of 2 long, rod-like stations rotating end-over-end, 1 each orbiting Earth and the Moon. The really bizarre part of this idea was that 1 flinger would throw a ship directly into docking with the other as it was spinning. Furthermore, the 1 at the Moon would be low enough that it could carefully set caught payloads onto the ground as it rotated around, and also pick stuff up off the ground to throw to the flinger in Earth orbit. The one at Earth was in some sort of eccentric orbit so it could get powered by crossing and rotating through different electrical potentials. I don't remember how the one at the Moon maintained its energy.

Anyway, back when I played Orbiter, a friend of mine actually made a mod for this whole system. IIRC he called it Ananki or some such, and even wrote several short stories set in a Cyberpunk world that used the thing. I did a lot of the testing and even with the high and realistic degree of automation and instrumentation in Orbiter, I have to say this was absolutely the most difficult thing I ever did in a space game. Timing your orbit to dock straight onto the end of a boom several kilometers long that's spinning fast enough to throw you to the Moon, then releasing at just the right point to go into the catcher's mitt at the Moon at even higher speed, and then get swung around and set on the ground before you could catch your breath, was quite a trip. It was absolutely impractical and certainly unworkable in the real world, but it was a cool mod

[MockKnizzle]

Wow, that's a crazy concept... I did some rough calculations for a catcher at the Mun, for a comfortable deceleration of ~3g you'd need a 10km station rotating at a little more than 1 rpm. Which, to be honest, doesn't sound all that crazy Smaller moons could get by with smaller stations, even. I'd hazard a guess that at least the catcher end of the system would probably be possible in stock KSP around Gilly, Pol and Bop.

I suppose the hard part is the timing, though, and how you'd even keep the thing in orbit.

Edited April 20, 2014 by MockKnizzle