NASA caused quite a stir with a recent announcement of their intent to return to the moon and establish a full-time colony there. Some have whole-heartedly applauded the agency; some have trotted out the traditional ‘waste of money’ objections that dogged the original Apollo missions; still others have cautiously expressed approval, but expressed concern over the lack of a distinct budget for the project and its potential to direct funding away from other avenues of research and exploration.
As a life-long space advocate, I’m happy to see any push towards establishing a foothold for our species beyond the limits of the Earth’s atmosphere, and I shall leave the debate on political motivations and budgetary restraints to those more qualified in such matters.
However, I would contend that attempting to establish a Lunar colony would be like trying to run before we can walk properly, and that our efforts would be better directed to establishing orbital habitats, if only as a pre-amble to colonising other planets or satellites.
First and foremost, we already have an orbital colony (albeit a very small one) in the form of the ISS – and simply maintaining and expanding it has proved to be not only difficult in an engineering sense, but economically challenging too. If resources are going to be expended on space colonies (and I believe they most certainly should be), why not build on the platform that has already been established? If I remember the initial plans for the ISS correctly from my youth, we’re far short of the bustling scientific outpost that we were supposed to have established by this point in time. Progress has been hampered by issues with the shuttles and rockets used to ferry materials and crew, granted; but it would be a mistake to assume that similar problems would not be attendant to a Lunar project.
Indeed, flights to the moon offer twice as many opportunities for dangerous mistakes with (or failures of) launch hardware – having gone to all that effort to get materials and men out of a gravity well, the risks inherent in attempting to land them at the bottom of another one make little sense from a logistical point of view. The gravity of the moon may be considerably lower than that of Earth, but it is still there, and in combination with the lack of an atmosphere it presents an obstacle that requires much planning to overcome. With an orbital platform, materials that make it out of the Earth’s gravitational pull are right where they need to be. Shifting stuff around in orbit is a cinch in comparison to landing it at the right location on the Lunar surface.
Gravity does play a factor in the argument for a moon base, in that long-term inhabitants of a space colony would require some gravity for their own well-being – long term exposure to zero-gee has a number of negative effects on human physiology, which present a serious hazard to anyone spending a long tenure in space. While the moon does offer a built-in gravity field for any potential inhabitants, it is less than a fifth of that found on Earth – meaning that all the same ailments associated with zero-gee would manifest after a certain length of time. Orbital colonies of any decent size would almost certainly be designed to be spun, hence producing ‘artificial gravity’ due to centrifugal forces that could easily duplicate the pull of Earth, thus obviating health problems.
A colony embedded in Lunar rock would certainly provide a great degree of protection from cosmic radiation and solar storms. However, theoretical research has demonstrated that an orbital habitat of sufficient size would provide ample protection in the form of its superstructure and internal atmosphere; additional shielding could be provided in many ways, from the low-tech (stationary rock outside the platform), through to the more science-fictional (magnetic fields, plasma screens and so forth).
The moon’s surface offers the temptation of easily accessed material resources. But if one assumes that a colony would require to be economically sustainable in the long run, regular interchange of goods with Earth would be a necessity, bringing us back to the ‘two gravity wells’ issue. A habitat in the right sort of orbit would pass fortuitously close to both the lunar surface and that of the planet below, allowing a flexibility of transport options as well as a refueling and maintenance stop between the two bodies. Hence an orbital habitat would be well placed to obtain resources from wherever they were most readily available, with a wider margin of safety.
Orbitals would inevitably be at risk from collisions with debris and junk in orbit. A sufficiently well-buried Lunar outpost would be less likely to be struck by falling debris, but by no means immune to a strike by an object of sufficient size; furthermore, it would have no chance of relocating if an incoming hazard was detected. The necessities of protecting an orbital (for example early warning systems, and laser or projectile weapons for destroying debris) would not be an insurmountable problem with sufficient resources and expertise brought to bear, and the technological advances made in the process would likely bring ancillary benefits – the energy and effort expended to excavate a Lunar base would have little payback value.
There are doubtless many other objections that could be raised to both scenarios (enough that I could write for days and not cover them all), but it seems to me that the trump card is with the orbitals; orbit is closer, cheaper and easier to get to, and offers more flexibility as a long-term outpost. Sure, let’s put men back on the moon, mine it for helium-3, research its history and origins. But it makes more sense to launch missions of that type from an already-established colony in orbit.
To use a military analogy, an orbital presence would act as a beach-head not just for exploring the moon, but as a jump-off for other locations in our solar system – maybe someday even further afield. It is said that even the longest journey starts with a single step; I would argue that there is no failure or cowardice in making that first step a realistically attainable one, as opposed to taking a flamboyant leap onto terrain whose hazards have already been established.