Earth-Moon L1 Lagrange point

[csmyth3025]

I made a topic search and couldn't find any references to threads about Lagrange points more recent than 2008. If I've missed one that is current, please redirect me there.

I'm wondering if the Earth-Moon L1 Lagrange point is still considered a good transfer point for people and materials going from the Earth to the Moon and from the Moon to the Earth. Also, I'm wondering if it would be practical to gradually boost the ISS into this position once it's "retired" in 2020. In this regard I'm thinking of the work that's being done with the Vasimr propulsion system.

Chris

 

[MeteorWayne]

Boosting the ISS there is not feasible. First of all, it would take too much energy (i.e. propellant). Second, it would be unprotected by the earth's magnetosphere. 3rd, how would you resupply the station, since nothing any spacefaring nation could boost supplies to that location. Remember, the ISS is not self sufficient...it needs water, food, and other supplies regularly.

See discussions in Space Business and Technology.

 

[neilsox]

MeteorWayne gave all good reasons, but maybe, with advanced technology. The Russian unmanned space craft that presently does most of the resupply of the ISS, can likely reach Earth-Moon L1 if fitted with a bigger first stage. Perhaps the existing Proton rocket would do the job. A super conductor loop on the ISS could possibly deflect enough radiation to allow female astronauts to produce their own replacement before they died from the radiation. Another possibility is a very high voltage electrostatic field to deflect radiation. Craft we will build to land people on the Moon and Mars can likely return astronauts from L1, but that may be decades in our future. It would take several shuttle trips to stock pile enough reaction mass or fuel at the ISS to move the ISS to L1 with Vasimr or equivelent
Perhaps the largest objection is the ISS is not optimised for a mission at L1. Near term there would not be much utility in having a manned station at L1, perhaps L1 will never be an important space location, even if we build a moon space elevator that passes though L1. Neil

 

[csmyth3025]

As I understand it, the Earth-Moon L1 lagrange point is ~56,000 km above the surface of the moon. This translates to a distance of ~328,000 km from Earth (on aversge). For all practical purposes, one can call this point "most of the way" to the Moon.

I have heard mention of utilizing a 2:1 resonance orbit as a possible "way station" to the moon - assuming we have a space tug or other means of getting there at relatively low cost.

Is such an orbit stable? What is the distance of this 2:1 resonance orbit from Earth?

Chris

 

[Boris_Badenov]

Private space stations edge closer to reality

[snip]

Beyond low-Earth orbit, Bigelow Aerospace also has its sights on expandable space habitats for Lagrangian Point L1, partway between the moon and the Earth.

Lagrangian points are where all the gravitational forces acting between two objects cancel each other out and therefore can be used by spacecraft to "hover" in one spot.

"If we can deploy and gang together modules in low-Earth orbit, you can do it in L1 ... and you are 85 percent of the way to the moon," Bigelow said. In fact, one scenario Bigelow Aerospace has already blueprinted is the soft landing of a trio of attached BA-330 modules — including astronauts — on the moon.

[snip]

 

[neilsox]

We tend to think of L1 as stationary, but it is not in most respects. With respect to the equator surface of the moon, it circles the moon about 13 times per year. Clearly the Sun also appears to circle L1 (about 13 times per year?), but the rate is at least slightly different. To get to L1 in a reasonable length of time, we are travelling at least 1000 kilometers per hour just before we arrive, so we have to do significant breaking. My guess is we are falling toward the Sun most of the time = we are spiraling away from L1 in a lumpy path. When we get about 1000 kilometers from L1 we will need to do a minor station keeping burn to return to approximately L1. If we wait until we are 3000 kilometers from L1, it will take about ten times more energy to return. I'm guessing, so please correct my errors. I have the feeling it is more complicated. Neil

 

[brellis]

When ISS deorbits, Russia plans to detach and fly its modules for future use as staging for missions to the Moon and beyond. They will keep it in LEO.

http://news.bbc.co.uk/2/hi/8064060.stm