There’s been something of a goal shift within the space industry recently. For quite a long time the focus was on returning to the moon and establishing a presence there which was born out of George W. Bush’s Vision for Space Exploration. However since then the goals of NASA, and indeed the goals of the most promising private space company, have shifted from going back to where we once visited to charting a course to virgin territory. Whilst its entirely possible that both NASA and SpaceX are just looking to capitalize on the attention that’s been focused on the Mars Curiosity Rover by announcing plans to send humans to our red sister there’s no denying that both of them are seriously considering the idea and it seems NASA might be looking at some rather radical ideas.
There’s been quite a lot of talk about what the best way to get to Mars would be and most of them involve a way station of some sort, something close to Earth that we can use as a staging ground whilst we prepare for the actual mission. The ideas have ranged from simply using the International Space Station to establishing a base on the moon. NASA has recently started investigating the idea of putting a base out at L-2 (Lagrange Point 2), beyond the orbit of the moon. Such a base would provide quite a few advantages and not just to potential manned missions to Mars.
You see the Lagrange points are special places where the gravitational effects of all the nearby bodies balances out so that you don’t really need to do a heck of a lot to remain there indefinitely. That’s quite desirable because it means you have to take up less station keeping equipment and fuel with you, making room for bigger and better payloads. It’s for this (and numerous other reasons) that the Hubble successor, the James Webb Space Telescope, will be placed at L-2. There’s also one other advantage to L-2 as well and that’s the fact that you don’t need very much energy to get anywhere in our solar system once you’re there, especially if you time it right and get some lovely gravitational boosts along the way.
Putting a station there and maintaining it would be no small feat however. At L-2 you’re well outside the protective magnetic field of Earth which means that any potential space station has to be heavily shielded against the solar winds and cosmic radiation that will bombard it relentlessly. This either means a much smaller single launch station (ala Salyut and Skylab) or multiple successive launches. It’s not an insurmountable task but it’s definitely a step up from the ISS in terms of complexity and investment required. The L-2 location also makes getting to and from the station much more complicated than getting to the ISS or even the moon and that raises questions about how to handle things like emergency situations and resupply flights. Again there’s no technical limitation to this but you’re well into envelope pushing territory when you’re working out a L-2.
At the same time though I do believe that if you’re considering a base at L-2 you’d also better consider doing something similar on the moon, especially if landing on other planets is your end goal. You see we do have quite a bit of experience in building space stations and a base at L-2 would be an organic progression of that. However what we don’t have is any experience in building habitats on the surface of other planets and the moon, with its lack of atmosphere and harsh environment, would be an amazing test bed for potential habitats on other planets. This is not to say that a moon base is better than something at L-2, they both have their pros and cons, just that if L-2 is a consideration then the place 1.5 million kms before it might not be a bad idea either.
I think the most exciting thing to come out of all of this is the fact that NASA is investigating some things which really are pushing the limits of our capabilities in space. I’ve long said that this is where they need to be focused as the private space industry has shown that they’re quite capable of doing the day to day stuff which should leave NASA’s budget free to do some really incredible stuff. With that finally happening I could not be happier as it means that we’re not that far off from becoming an interplanetary species.
In principle, at least.