New Mars Forums

I've seen a lot of ideas involving bigger chemical launchers, two stage chemical rockets, and single stage to orbit in this site, but those probably aren't going to get us the prices low enough for a significant number of people to colonize mars. What pet scheme do you have to drastically reduce launch costs? I'd like to hear everyone's no matter how hair brained. Hey, one of them might actually work. Here is mine to start off: A wave rider with a fabric wing that can change shape to optimize to any speed that is covered with thin film solar cells. Then at the rear it has a propeller that consists of smaller wave rider kites on Kevlar or spectra cords spinning about the hub to produce thrust, and spun by electric motors. The craft slowly climbs and accelerates so that the air density goes down to limit heating. To make up for the reduced air density the propeller/kite cords are unwound further so as to increase the propeller disk area. Feel free to criticize and please share your own ideas.

Yes, I realize that most of the oxygen on the moon is from it's original formation, but isn't all that in aluminium and titanium oxides? I don't understand how that oxygen could be removed just by heating the regolith up to a few hundred degrees and how is could be easily captured. Maybe it is possible, but I thought that if extra oxygen was deposited by solar wind it would not have combined yet with the other elements and might be more easily accessible. I'm not a chemist however, so maybe a few hundred degrees is enough to get at the main store of oxygen. I'd love to be enlightened if it does work, it makes everything so much easier!

I would vote for the rotating space habitat. It could be built closer to earth and the moon which would simplify consruction and transport, it could also be built cheaply from near earth astoroids. Plus with it could be movable with a small high isp thruster. I think the largest argument however is the optional gravity. transport from the colony to earth and vice versa involves only one steep gravity well and that only for outbound trips, were as a martian dome has a gravity well to escape in each direction. The space colony could have 1 gee which is IMO a major oversite in the mars colonization groups. This way, the inhabitants could return to earth if so desired. Zero gee would be avalible aswell for recreation and manufacturing to keep the inhaditants occupied.

Grypd,
Would the tether be spinning or just grabing the cargo and acellerating it quickly and then hauling it up?

A rotovater wouldn't be moving in relation to the surface at it's low point so that's not an issue, but I'll admit it requires quite a bit of infrastructure. Not an unreasonable amount in my opinion, at least for a small one, but I see your point. As far as a track on the ground, which you do realize is quite a bit of infrastructure in and of it's self, might be made fairly economically in two ways. First, in the lunar night the surface temperature is well below 120 K, the temperature required for high temperature superconductors. If some HTS dust/grains could be brought to the moon, they could be sprayed on the ground to make a diamagnetic path. Then with some fairly high power superconducting magnets on the "train" you sort of hover on top of it. Later maybe a reflective sheet could be laid over the track for operation during the day. The main questions here are: How much dust is necessary for a reasonably heavy train and will the train be able to stay on the track without huge amounts of small thruster fuel? The second option would be to fit a lunar rover with a magnetron to produce microwaves and a plow. It could be driven along the surface in a strait line using it's plow to heap dust into two parallel ridges with sharp tops. Then the microwaves could sinter the dust together to make an aluminum/titanium track. This still leaves the question of friction however, if I remember the fastest manned train on earth used a rocket and Teflon runners on the track.

Why use high power magnets? It seems to me that an old fashioned cable and net could do the same thing, plus with a long enough spool of cable you could lower the acceleration, though it's still going to be pretty extreme. The main problem I see is that the orbiting base is going to have to be quite large in relation to the projectiles/ scramjet. Otherwise the transfer in momentum will pull the whole thing out of orbit before the ion thrusters can make up the difference, although with a more elliptical orbit it might work. that's something I have virtually no understanding of however so I'm hesitant to suggest it. I like the main Idea of it though. Maybe in a few decades NASA will want to unload the ISS and it can be moved into the proper position with some more modifications.

How about a rotovator? (correct term?) With the lower gravity, orbit height, nd vacumn I read somewhere that it could be built using current materials like some sort of kelvlar rope. This has the added bonus if I understand it right of being able to throw things out at escape velocity from lunar orbit. It's basically a twirling rope or cable that is turning in the opposite direction that the middle of it is orbiting. It's also as long as orbital height so that for brief periods it appears to be stopped at the surface. Of course it will need to have a center base station and some sort of engine to make up for flinging cargo into orbit, but if the middle mass is large enough this could be a relitivy low thrust engine that runs continiously, like solar thermal.

That may work since the aerospike, the way I understand it at least, makes the shock cone stand out further from the body so one can assume that the plasma would be diverted. However I see two issues that need to be adressed. First, thoug I don't know how fast it will reenter, if it's generating plasma the thermal and even visible radiation could do a number on the engines and the shell. I think, from my limited knowlage, that this is the main reason why they have ablative heat shields on capsules and tiles on the shuttle, the plasma is itself is diverted by the detached shock cone, but the energy it radiates reaches the ship. Of course this depends on how fast you are rentering. I read that without blunt bodies and an attached shock cone a fast re-entery would reach 7800 K! Secondly, the aerospike reduces drag, on the minuteman upt to 50% percent. Do you really want to lower the drag? Depending on how high up it is and it's velocity upon stage seperation you may not have enough time to slow down with that small of a frontal area and that low of a Cd. Of course you could use a drouge parachute like the soyuz but for a large first stage I'm not sure that's possible. Best of Luck though, I'm somewhat partial to these non-standard wave drag reduction devises.

I read an article once that said that moon dust could be solidified or melted together with ordinary microwave equitment. I guess the technical term is sintereing.  So one could just zap the dust on the ground and not have to worry about it anymore. Of course that's kind of a mundane use, I was thinking that it might be possible to build a sort of 3D printer that blew moon dust from a resovoir using mini railguns to build large objects. It would blow a layer on and then zap it with microwaves to stabalize it. Might work even better in orbit as the lack of gravity could allow abituarily large structured to be printed. Great for solar collectors and spacecraft hulls.
here's the link http://www.space.com/adastra/adastra_mo … 60223.html

I read the discover article too, and it did say that hydrogen is the absolute best for stopping them, but it also mentioned that a magnetic field could stop them. granted it would have to be a large superconducting magnet, but would this be so hard to do in space? it seems to me that as long as you kept it in the shade and cooled it down with helium it would stay pretty lightweight. Granted it's going to weigh something, but would it be possible for it to double as a mag sail or something? The electronics for the ship could be magnetically shielded.

Yes you are right I pasted in the wrong number. The total power output would only need to be a meissly 100 megawatts to equal drag, throwing out about  2 kg of hydrogen a second. Unfortunatly that''s still a lot of drag and a huge amount of beamed energy. You have another problem with laser energy "70 seconds maximum lase duration" is a quote from the webpage you posted a link to. That's not much time to go from 0 to mach 25.

Yeah, I said electric propulsion because I think the plasma drag reduction device would absoarb the mircowave energy if it was aimed to close, although if the waverider shape is optimised for mach 25 it may be long enough to get by without a towed recctenna. I belive the bigest problem with microwaves is their inability to focus on a tight spot, they need a large reciver