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.
To put it bluntly we’ve been spinning our wheels in terms of human space exploration. It was well over 40 years ago that we first placed one of our own on the moon and in the time since then we’ve tentatively sent out our robotic companions to do the exploring for us, staying in the relative safety of low earth orbit ever since. There is no one entity that we can blame for this, more it is a sign of the malaise that took over once the space race was won and there was no longer any political motivation to push the final frontier further. The last decade has seen a few ambitious plans put into motion in order to start pushing that envelope once again, but none of them are to bear fruit for at least a decade.
Of course I’m not expecting that we’ll see another space race any time soon, we’re far too engaged in fixing economic problems right now for another pissing contest between superpowers. However that doesn’t mean that the groundwork can’t be done for a time when countries are ready to pursue space travel with renewed vigour and NASA is doing just that with their roadmap for space exploration:
Human and robotic exploration of the Moon, asteroids, and Mars will strengthen and enrich humanity’s future, bringing nations together in a common cause, revealing new knowledge, inspiring people, and stimulating technical and commercial innovation. As more nations undertake space exploration activities, they see the importance of partnering to achieve their objectives. Building on the historic flight of Yuri Gagarin on April 12, 1961, the first 50 years of human spaceflight have resulted in strong partnerships that have brought discoveries, innovations, and inspiration to all mankind. Discoveries we have made together have opened our eyes to the benefits of continuing to expand our reach.
NASA’s roadmap lays out 2 options for the future of manned missions beyond low earth orbit with both of them converging on the ultimate goal of sending humans to Mars. The first being called “Asteroid Next” which would see our next target being a near earth asteroid favouring the development of deep space technologies. The second is “Moon Next” which would see humanity return to our celestial sister and use it as a test bed for technologies that would enable humans to survive in Mars’ harsh climate. Both options are equally valid, but they are not without their drawbacks.
First let’s have a look at Asteroid Next. The most interesting part of this idea is the establishment of a Deep Space Habitat at the Earth-Moon lagrangian point. Now you might think that this is somewhat pointless when we have the International Space Station but establishing a base beyond the comforts of low earth orbit poses many significant challenges. The ISS as it stands doesn’t have the required shielding to protect it’s occupants past its current orbital altitude and a habitat at L1 or L2 would need significant redesigns. However such rework would form the basis of the module that would carry our explorers to Mars as the requirements for a habitat and interplanetary transport are nearly identical.
Having a base at the lagrangian points also opens up nearly any destination within our solar system and could serve as an excellent base for future missions. The energy required to go from one such points to anywhere in the solar system is quite minimal and well suited to high efficiency engines like ion-thrusters. Having a presence out there would make a perfect base for sending up unmanned equipment prior to sending them to Mars or beyond.
Asteroid Next however doesn’t make any mention of technology development for Mars settlement meaning that the missions to Mars that followed would probably be short lived like their Apollo ancestors were. Asteroid Next then is very much like its predecessors in that regard, being a lot more like a one-shot event that something that would be repeatable for decades to come. This would see us push the boundaries much more aggressively (we could conceivably send a DSH to Mars by 2030) but at the risk of history repeating itself, seeing such missions as one offs.
Moon Next then sees us forego advancing deep space technologies in favour of returning to the moon and establishing a base there. This delays developing deep space technologies in favour of developing, testing and deploying habitats and supporting infrastructure in a much hasher climate than what will be faced on Mars. Technologies like the Deep Space Habitat will still need to be developed as they are crucial for the journey to Mars however Moon Next would see them developed well over a decade later than Asteroid Next. Moon Next would also see humanities base of operations be that of a small moon colony rather than a base at a lagrangian point which is advantageous in terms of resources (if we can develop technology to harvest some of the Moon’s resources) but does require much more energy in order to launch missions from there.
Going to the Moon before Mars might seem like we’re just repeating what we’ve already done but establishing a base there would be highly advantageous to future missions, and not just future exploration. There are many cases for radio telescopes on the far side of the moon (shielded from all the signals that currently pollute Earth) and there’s the very tantalizing prospect of constructing giant optical observatories that make us of the non-existent atmosphere and low gravity. However going for the Moon first means that a potential Mars shot will be delayed much longer than it would be if we pursued deep space technologies first.
After considering both options I believe our best bet is to go with the Moon Next option. If Mars was the only goal we had Asteroid Next would be the way to go but the potential benefits of a lunar base are just too good to pass up, even if it means not getting to Mars for another decade. Many of the technologies used in developing a lunar base will be transferable to both Mars missions as well as other deep space activities. It’s a tough choice for NASA though as the arguments are equally strong for supporting Asteroid Next and I’ll be watching the debate over these two ideas unfold with a keen interest.