Sorry if this is OT for the thread but if you are going to have a landing strip why not an arrestor cable system. Could be an interesting material science problem!http://en.wikipedia.org/wiki/Arrestor_cableI also remember reading somewhere, probably in the halcyon daze of O'Neillan Space Colonisation, of an inverse Lunar Catapult using electromagnetic breaking for dumb (and high g) tolerant payloads. But the idea was to get the mass into orbit and process it there!
Plus, the energy can be captured (for a wheeled system) by onboard generators and beamed to a base or ascent vehicle.Such a system could also be used for launch from the Moon.
Lets say we have our strip, as wide as an air strip, consisting of super fine absolutely level dust and perhaps bounded by all the larger dust and rocks we have raked aside.
It already exists, but it is on Mimas, covered by very fine snow, and needs to be able to accept 100-150 m/s fast objects only, due to small size and density of Mimas.Ultimate skiing experience.
Here's a thought, the rim of a wheel toucing the ground is not moving horizontally relative to the ground, unless it's skidding. So if you spin the wheel up to the correct speed before touchdown, (about 14,000 rpm for 1 m radius wheels at orbital velocity), the main friction should be on the axle bearing. Which could be magnetic.
If you're using a wheel with a magnetic bearing, then couldn't you do the exact same thing BUT IN REVERSE??? (in other words, accelerate with wheels to--or near to--lunar orbit) It seems to me that if the wheel idea could work, it would work it the opposite direction as well, except you would probably use over-head power lines to power the craft.BTW, a wheel approach could possibly work since the fastest land speed record is 341 m/s, and I'm sure the limit is not the wheels. This surely needs some advanced materials, but seems within reach of material science.
BTW, a wheel approach could possibly work since the fastest land speed record is 341 m/s, and I'm sure the limit is not the wheels. This surely needs some advanced materials, but seems within reach of material science.
The whole concept of a lunar landing strip, wheels or not, strikes me as a completely nuts.
Well, solid aluminum is all well and good, but mono-crystalline silicon has about 20 times the tensile strength. It would be very difficult, indeed. (There are also flywheels that operate at supersonic speeds, so this seems possible, especially in the Moon's lowered gravity.) Also, by tapering the thickness of the material, you can get away with lower tensile strength than otherwise (much like a space elevator).
This would require some fairly robust sort of snowblower like device, but still far less effort than the industry to construct the components for either a high performance mass driver of 100km that could slow large objects at 3g, or a lower performance maglev that extended much further than 100km, to allow slower deceleration.
You would need a lot more than a snowblower. You would inevitably have to fill craters and rilles, knock down local hills, move or blast through boulders and so on. So you need earth-moving (err moon-moving) equipment at least similar to what would be required to build a 100km stretch of freeway on earth. This alone will run into hundreds or thousands of tons with conventional equipment. Then you need the equipment and facilities to maintain it. Given how nasty and abrasive regolith is, wear is going to be major factor. It's not soft and fluffy like snow... try running a hundred km of fresh granite dust through your snowblower All of the above on the highly dubious assumption that the dust cushion idea is workable.
In terms of comparing to a 100km highway, about the only similarity is '100km'. The moon is has large flat areas, covered everywhere in regolith, you dont need to connect two specific cities so it is ok to avoid those mountains.
I'm having trouble thinking of processes on the moon that would have a similar result, but I'm not a planetary geologist by any stretch.
The Mares were formed by lava flooding. Should be relatively flat.
Hmmm... So, you can't build a landing strip, huh? Well, what about a MONORAIL! Monorail, Monorail!
There is plenty of iron on the moon to make a wide landing strip from.
Quote from: A_M_Swallow on 12/13/2008 05:12 pmThere is plenty of iron on the moon to make a wide landing strip from.Not sure I get you. Are you saying luna materials are not inferior because there is iron?
KelvinZeroGreat minds think alike. Just found this and thought you might be interested.http://altairvi.blogspot.com/2007/11/lunar-slide-lander-1979.html"Geolunar Industrial Transportation for Low Propellant Expenditure with New Energy Management Concepts for Lunar Access," IAF-79-F-120, K. A. Ehricke; paper presented at the 30th Congress of the International Astronautical Federation, Munich, Federal Republic of Germany, September 17-22, 1979.
So solving for h with a 100 km landing strip we get a end 'height' of the 'flat' runway of 2.8745 km!BOTE + online quadratic equation solution.Am i wrong? Or is that a lot of Moondust!(Reverse) Lunatrons (from "Man and the Planets" Duncan Lunan 1983)150g 1km100g 3.3km20g 14.4km1.7g 160kmStill like the idea of a tailhook tho.
With careful design most of the energy could be disappated in dust hitting dust rather than in grinding away the hull of your craft.