NASA and the European Space Agency (ESA) are debating on whether to send the next human space mission to the Moon or Mars. What say you?
I say the Moon.
It's amazing how much of NASA's Journey to Mars so far has been focused on just the launch vehicles (or rockets) that could get us there and back.
Sure, the US space administration has produced some excellent prototypes of Mars surface rovers, and they've conducted a great study on the benefits of pressurised versus unpressurised rovers, among other things. Yet relatively little progress has been made on “in space” and “on Mars” habitats.
Yes, the life support systems on the International Space Station (ISS) seem quite robust and manageable for the time it would take to get there (roughly 7 months each way). But these still require a fair amount of supplies to be delivered from Earth every 3 months or so.
Even the mighty SpaceX, which may get there first, is very much focused on big rockets and their Mars Colonial Transport; not so much on the other systems you would need to begin a human settlement. And yet most Mars missions are planning for a 1.5-year stay on the planet's surface.
To succeed, humankind must learn to be self sufficient in space, and for extended periods of time. Clearly, there is much to be done beforehand, which is why I believe that after Earth, the Moon would be the next best place for us to be -- to fully test “all the other stuff” needed for long term space habitation.
Why the Moon
The Moon is surrounded by a vacuum; and for all intents and purposes, so is Mars with its <1% atmosphere. The Moon has ice on it; so does Mars. This is notable as most Mars mission plans look to make use of surface water to reduce the required mass to be transported, and to potentially produce rocket fuel for the return journey. Both pose similar radiation issues.
Indeed, for most of the things that matter, the Moon is very similar to Mars...with one very important exception. Our moon lies a mere 3 to 4 days from Earth. A round trip to Mars, meanwhile, could take 1.5 years or more -- roughly 7 months there, a 3- to 26-month wait for the Earth and Mars to be correctly aligned for the return leg, and 7 months back.
On the Moon, any emergencies or supply shortages could be addressed within days. On Mars, it could take years. (If you've seen The Martian, you'll agree that a year is a long time to wait.)
Most Mars missions also recommend a long-term settlement on the surface given the immense cost, time and effort to get there. Ironically, this would require a lot more mass to be delivered to the surface - approx. 10 times more hardware than for the Apollo lunar missions, according to some studies; and about 10 times the number of rockets launched.
Meanwhile, with the Moon just a short blast away, folks are less likely to worry over short visits, where even the descent capsule could act as a temporary surface habitat.
In any case, I believe the decision to go to the Moon or Mars should not rest on whether we've been there or not; but rather on how we can best learn to live in long term settlements away from Earth.
What better place to learn that than on the moon?