Communists on the moon !

Loser · #1 December 18th, 2003, 06:21 PM

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 · #2 December 18th, 2003, 06:27 PM

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 · #3 December 18th, 2003, 07:38 PM

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 · #4 December 18th, 2003, 08:01 PM

Quote:

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 · #5 December 18th, 2003, 08:55 PM

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 · #6 December 19th, 2003, 01:26 AM

Quote:

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 · #7 December 19th, 2003, 01:53 AM

Quote:

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