This article also appeared in the Summer 1999 issue of Space Front, a publication of the Space Frontier Foundation.
Been There, but Have We Really Done That?
by Mike Combs
Copyright © 1999
No, that's OK, I assure you it's not a case of my needing to get my lithium dosage adjusted. I'm referring not to the little green guys of mythology, but to perfectly-human Mars colonists. Or more accurately (since the colonization has not yet actually begun), the wannabes. (OK, in all fairness, I must admit to being a wannabe O'Neill settler myself. Yes, I freely confess up front that I'm one of "Gerry's kids".)
Some of my fellow space activists seem to have set their targets squarely, and almost solely, on the planet Mars. I'm not talking about activists who are favorably disposed toward the idea of humans on Mars. Heck, I like the idea too. I only mean the kind of enthusiast that, when you discuss a return to the moon with them, grow impatient, seeming to view moonbases and lunar development as an unnecessary detour on the road to the red planet. Is this view justified?
Some of the arguments used to support this viewpoint are:
Been there, done that - We don't need to go to the moon because we've already gone to the moon. Time to press on to the next destination.
Between 1969 and 1972, the Apollo project landed a dozen men on the lunar surface in six different locations. All of the landing sites were within 26 degrees North and 9 degrees South of the equator due to orbital requirements, and none of them were on the far side due to communications issues. The total surface area of the moon is roughly the same as that of Africa. If extraterrestrials were to briefly land twelve explorers in six scattered locations on the continent, all well north of the equator, could it be said they had in any substantial way explored Africa? What could they have missed? Where lunar exploration is concerned, we have literally only begun to scratch the surface.
Also, a Mars transfer orbit is about 480 times the distance of a lunar transfer orbit, a fact which should shatter the perception that Mars is just the next stop on our space itinerary. It might be advisable to accumulate some additional manned deep space flight experience prior to embarking on a two-orders-of-magnitude-more-difficult journey.
The moon is dull - There's no atmosphere on the moon, and there's no possibility life ever evolved there.
The Martian atmosphere is one percent as dense as ours, while the moon has zero atmosphere (practically speaking). So I suppose some wag could say the difference between the lunar atmosphere and that of Mars is a difference of one percent. But more seriously, the atmosphere of Mars will in no way mitigate the difficulties of providing needed pressurization for humans in comparison to the Moon. While the atmosphere of Mars might be useful for In-Situ Resource Utilization (ISRU), it also creates sandstorms, so one has to take the bad with the good. Deriving useable oxygen from lunar soil is admittedly more complicated and involved than generating it from Martian CO2, but it's certainly not impossible.
As for no possibility life ever evolved on the moon, I submit we do not yet know that life ever evolved on Mars. Some scientific evidence seems to support the idea; some seems to dispute it. The jury is still out, and in the meantime I think it would be a mistake for us to build the justification for the continued human exploration of space on the unsure foundation of Martian microbes. This is one structure we space advocates can't afford to have come crashing down on us in the event there turn out to be no microfossils on Mars to study.
One might have thought the late discovery of ice at the lunar poles would have been the death of the argument that we don't need to return to the moon because we've already studied it, and already know what's there. Who can rule out that other, even more unexpected lunar discoveries lie ahead, given continued exploration? I suspect our moon has many surprises yet to be revealed.
We don't need to go to the moon in order to go to Mars - Going to the moon just to "try out" the technologies needed for Mars exploration will only serve to delay achievement of the final goal.
I won't advocate returning to the moon simply as a trial run for landing on Mars (although some have made a good argument regarding the relative return-trip-times in the event of an emergency). And it's absolutely true we don't need to go to the moon in order to go to Mars. We also didn't have to build a reusable space transportation system, nor an Earth-orbiting space station, in order to land men on the moon, even though space thinkers had advocated these from the very beginning of lunar exploration proposals. And thirty years later, what do we have to show for skipping over these intermediate steps with regard to subsequent lunar development?
"Mars First" proponents sometimes bristle at the comparison to Apollo, but I think it's justified. With Apollo, we decided to forego in-space infrastructure in order to reach the goal more quickly. I'm aware Mars advocates have made enormous strides in terms of reducing the costs of a Mars mission relative to Apollo, and I think ISRU to generate fuel on Mars is a brilliant proposal. But I feel it would be a mistake to proceed to the Red Planet on these alone. We need additional in-space infrastructure.
Consider this: A pound of ore can be lifted from the moon to a high Earth orbit for only 1/20th the energy as from Earth to that same orbit. Thus, any ship built from lunar ores in that orbit will start out with a tremendous advantage over any spacecraft built on Earth, crammed down into the cargo bay of some Earth-to-orbit system, and then rocketed off piecemeal.
A ship for crews journeying to Mars may require both closed-cycle life support systems and artificial (spin) gravity. Both necessitate large spacecraft designs; the former due to buffering considerations, the latter due to Coriolis-effect concerns. If we begin with assets of lunar mining, and high-orbital refining and fabrication available, such huge designs become economically practical. So even if a return to the moon is not a prerequisite, it is certainly an enabler, both for Mars voyages or any other space goal one can name.
Only Mars has all of the elements needed for a space civilization - As the moon is lacking in hydrogen, carbon, and nitrogen, Mars is the place to go to build the future.
One space advocate I was recently debating with stated that the resources of Mars "make the Moon pale in comparison". With the recent discovery of lunar ice, carbon and nitrogen may be the only remaining Martian resources scarce on the moon. (And it's worth pointing out that all of these resources are available in most Earth-approaching asteroids, at the bottom of very shallow gravity wells.)
But there's one overwhelming advantage of the moon's resources over those of Mars: lunar resources are sufficiently close by that their utilization could have returns to the economy of Earth. I think this is vital for getting the space enterprise started in the first place. Martian resources are good for one purpose and one purpose only: to construct habitats to live on Mars. Lunar resources can be used to build habitats to live in High Earth Orbit, as well as Solar Power Satellites (SPS), enormous GEO communication platforms, and even ships for solar system exploration.
But to be fair to both sides, does the "Back to the Moon" crowd sometimes overstate their case? Sure.
I've sometimes heard the moon advertised for astronomy. While the lack of atmosphere is certainly an advantage over Earth, what is the advantage over High Earth Orbit? We can use the bulk of the moon to shield a radio telescope from the radio noise of Earth, or we can use less than a millimeter thickness of aluminum; either would do the job. "Farside Observatory" has been discussed so much it has almost become like a real place. But "High Earth Orbit Observatory" can look in any direction you like, not just where the moon is presently pointing it. As can orbiting optical telescopes consisting of vast arrays of floating mirrors totaling several city blocks in area. However, the best source of raw materials for building both of these high-orbit observatories will likely be the moon.
Then there are the lunar energy production proposals: Helium-3 and solar. Those fusion reactors do not yet exist even as paper designs, so I would leave that out of immediate consideration. This leaves solar, which, in my opinion, is best done not in a place which is dark 50% of the time, but instead in free orbit. But given the outstanding advantages of using lunar resources for SPS construction (or any other high-orbit enterprise), it still remains that the moon figures prominently in a space-based solution to our global energy needs. And we need that solution up front, if for no other reason than to forever silence the "But what do we get out of space?" crowd.
A stepwise, walk-before-you-run approach including a return to the moon, the establishment of lunar mines, and the use of lunar resources in High Earth Orbit manufacturing facilities will in the long run place us on Mars, or at any other destination in the solar system we may find desirable. And it may even pay for itself along the way, which means it might stand some chance of getting off the ground.
Going to Mars is a noble goal, and is worthwhile from both a scientific discovery and human adventure standpoint. I'm certain we'll walk those red sands someday, and very much hope it happens in my lifetime. But I think our reasons for sometimes being tempted to set our moon aside so we can get on with Going To Mars Real Soon have more to do with romance than with the laws of physics, and with Bradbury than economics.
We space advocates sometimes like to draw an analogy between the settlement of space, and the settlement of the New World. In this comparison, Low Earth Orbit becomes Plymouth Rock, the moon and cislunar space is the eastern seaboard, Mars is the mid-west, and the belt asteroids are those California hills which we all know are made of gold (though now, volatiles are more to our liking). To my mind, going to Mars before we have economically-developed and inhabited the moon and near-Earth spaces is like the Pilgrims landing on Plymouth Rock, quickly building Conestoga wagons, and then immediately pressing on to Oklahoma. First, let's return to Boston (we hardly even got to know the place in that one, brief visit so long ago). First, let's build Philadelphia. The Westward Movement, and even the Gold Rush, will each come in their turn.