Communists on the moon !

[JurijD]

hehe, Its really interesting to see how discussions can get derailed I read the whole post again and I saw it go from life on Mars to Europa to a discussion on Communism to the Middle east (yeah, that has to come up sometime )

Back to the Moon... I think space tourism could really open up space. I mean if we can make going to space profitable and fun for everyone we can eventually start channeling funds to exploration/development and colonize the moon.

Hope those Xprize guys do it soon... does anyone know when the first launch is planned for?
(better star saving up those 100 grand lol

[Loser]

Sure L4 and L5 are great places to put stuff if you want to send it somewhere else on the cheap, but they're not such great places to work.

Microgravity is very inconvenient. Not only is it difficult to keep humans healthy in microgravity, but it's hard to work, to move things around (inertia and torque messing with you), and many machines must be built very differently to work without gravity.

The lower gravity on the moon would still be troublesome, certainly, but it would help.

Before someone brings up the spinning-wheel space station concept I'll point out that it is very difficult to do right. The problem is that as people move through the station, the station itself will move around in space. A great deal of fuel will be needed to keep it at it's intended location.

You might remember seeing pictures of American Astronauts running around the inside of Skylab, no? Yeah, they were knocking that like box all of the place while they did that, and Skylab was not properly fitted to keep it's orbit anyway.

Since an object near either the L4 or L5 positions will be gently pulled toward the actual specific Lagrange Points, you might be able to put a spinner up there and just let it go, depending on the attraction of Luna's Trojan points to keep your station where you want it. I don't think that's such a good idea, myself, and every damn thing in the station would have to hold real still when time comes for anything to dock with it.

[geoschmo]

Skylab was a relativly small space craft. Anything we are likely to put at an L4 L5 point is going to be much bigger. Especially if we build something with roational motion for internal gravity. That would have to be a pretty sizeable craft with a big enough radius to eliminate the detrimental physical effects on the human body of the difference in gravity along the length of your body. So we are talking about a large station with probably a multinational effort with room for dozens if not hundreds of full time occupants. Such a station will have pretty significant mass and so will not be as affected nearly as much by people moving around inside it.

Geoschmo

[ December 18, 2003, 16:16: Message edited by: geoschmo ]

[Loser]

The problem is that it will be affected. There is no friction to keep all the little bumps and jars from building up. And this isn't just about human bodies, every piece of equipment, inventory, and even the circulation of water and air will move that baby around. Sure when compared to the mass of the relatively stationary architecture of the station they seem small, but they're always moving and it will add up.

But, as I said, the great thing about Lagrange Four and Five is that an object with an orbit close that Luna's Trojan orbit will be pulled to that specific velocity/trajectory over time. I'm just not sure this balancing force will be sufficient.

[geoschmo]

That's the point, they are very small, and they don't add up. Unless all the vectors are the same they don't. Equipment would be planned and balanced in such a way that the majority of their forces cancel out, and the random movements of a bunch of people going in different directions about the interior of the station will for the most part cancel each other out. The result will be a small net change in whichever direction has the largest amount of force being applied. But the net change will be well within the tolerance allowable by ordinary station keeping thrusters. Docking equipment has tolerances and extra reinforcment to allow for minicule variations, and if a particularly delicate manuver were neccesary, you could always broadcast a warning on the intercom, but I don't think it would be neccesary at all. The computers and thrusters ought to be able to easily handle it.

Geoschmo

[Loser]

I will stand by my contention that the constant, semi-random displacement forces involved in real people living their lives inside a spinning-wheel space station are sufficient to make the concept wholly impractical without significantly different means of station-keeping. Every bit of thruster fuel has to be lifted to orbit as well, and I contend, as well, that it will be expended at a fairly rapid pace.

I will allow that Lagrange points four and five may compensate for this, but I wouldn't hold that up as certain until I get a better grip on the scale of the forces involved on both sides.

As I so not expect anyone here to come up with a nice, concise, understandable model that will prove this one way or another, I'm perfectly happy to leave the discussion as it stands. I have pointed out everything I think is involved, and I think you and I have different expectations where the scale of the disturbing forces are concerned, Geo.

Of course, if someone does want to do the math and whip up a nice computer model, I would be overjoyed to get my hands on the toy.

[rdouglass]

Originally posted by Puke:
Just think about the whacky adventures that the commander of Luna-one, our first moon base, will have!

and that was all over FOUR YEARS AGO!

More like TWENTY four...

Am I old! Yeah, I got the reference to Martin Landau and Barbara Bains...

[Cyrien]

I think he is more refering to it all happening in 1999 in the original show.

I love old Sci-Fi in both book and movie form with their predictions of what their future our past/present would be like.

[Suicide Junkie]

Originally posted by Loser:
I will stand by my contention that the constant, semi-random displacement forces involved in real people living their lives inside a spinning-wheel space station are sufficient to make the concept wholly impractical without significantly different means of station-keeping. Every bit of thruster fuel has to be lifted to orbit as well, and I contend, as well, that it will be expended at a fairly rapid pace.

I will allow that Lagrange points four and five may compensate for this, but I wouldn't hold that up as certain until I get a better grip on the scale of the forces involved on both sides.

As I so not expect anyone here to come up with a nice, concise, understandable model that will prove this one way or another, I'm perfectly happy to leave the discussion as it stands. I have pointed out everything I think is involved, and I think you and I have different expectations where the scale of the disturbing forces are concerned, Geo.

Of course, if someone does want to do the math and whip up a nice computer model, I would be overjoyed to get my hands on the toy.

Assuming everything stays inside the station, the center of mass will remain in a consistent position.
If you set up the station to be initially stationary at the L-points, the center of mass will remain there no matter what the people inside do, due to newton's laws.

When you open airlocks to let people and cargo in and out, you will only need to compensate once. Given a large station, and reasonable care the motions induced by external traffic will be minor.

Using an Ion thruster or even a magnetic sail to maintain stationkeeping would be very useful too. Very little thrust, but you have plenty of time and don't need to accelerate much.

[geoschmo]

Originally posted by Suicide Junkie:
Assuming everything stays inside the station, the center of mass will remain in a consistent position.

No, I don't think this is right either. Loser is right when he says there will be some reaction to people walking around the inside of the station. As they exert force against the deck plates to go in one direction the station will have an equal reaction in the opposite direction. I just think he's way over estimating the amount the reaction will affect the station. The difference in mass between the person and the station means that almost all the energy moves the person and almost none of it moves the station. So while there will be a force applied to the station it would be imperceptable I believe.

Geoschmo