In contrast to my post last week about some recently uncovered qualities of lunar craters that will likely make any plans to settle or develop the Moon much more difficult, I am going to focus on Mars and the challenges it brings, because while electrified polar craters is a problem, the dilemma between pursuing Lunar or Martian exploration or both isn’t clear cut.
Last August, Lawrence Krauss wrote an op-ed for The New York Times entitled A One-Way Ticket to Mars, in which he argued that many of the challenges of sending humans to Mars are compounded if they need to return, and thus we should look to send astronauts on a one-way trip to mars rather than a round trip.
I agree with Krauss, with a few modifications. I think that a fundamental question that needs to be asked when pursuing human space exploration is: Why are we doing this? Sending astronauts to the Moon and Mars may be inspiring, but if we aren’t satisfying any major goals in doing so, we’ve accomplished the modern equivalent of the Pyramids of Giza: a monument to human accomplishment with little practical value for the future.
So if and when we send an astronaut to Mars, we should be doing it for a reason. A replay of Apollo with a flag-planting, a prance around the planet’s surface and a return flight would mean that we have failed fundamentally in how we think of space and would probably lead to a similar result: a few decades during which humans don’t venture above Low Earth Orbit.
Mars is not easy to reach. At it’s closest, Mars is about 150 times the distance between the Earth and the Moon, a trip that took the Apollo astronauts three days to complete. Furthermore, Mars is only in that position about once every two Earth years. While the Ad Astra’s VASIMR engine promises to bring the trip time down to 40 days, Mars is much less accessible than the Moon is and this brings a raft of difficulties with it.
The difficulty that Krauss rightly concentrates on is that of cosmic radiation, which are high energy particles traveling near the speed of light. Earth’s atmosphere protects us from this radiation as it collides with air molecules in the upper atmosphere, dissipating the ionizing radiation before it reaches the planet’s surface. In deep space, the only protection is what the thin walls of the spacecraft can provide, which means that astronauts are exposed to many times more harmful radiation than those of us dwelling on the Earth’s surface.
Another related issue is that of the Sun’s activity. Every 11 years, the Sun’s poles reverse their magnetic orientation, and during this process, the Sun’s surface breaks out with a collection of darkened patches called sunspots that arise out of the tangling of magnetic fields within the star. As these magnetic fields interact, they can sometimes “break”, releasing a vast amount of energy in the form of a solar flare. Like cosmic radiation, this can be very harmful to the relatively unshielded astronauts.
As such, the best time to send astronauts into space, especially on such a long voyage as to Mars, is during a solar minimum, when the Sun’s magnetic poles have completed their realignment and the surface is relatively free of sunspots.
Because of this radiation risk, spacecraft delivering humans to Mars will necessarily be designed with a good deal of radiation shielding, which will be heavy, increasing the cost and difficulty of sending the craft to Mars and making the return trip even more difficult that it was. Protecting astronauts from 40 days of radiation is difficult. Doubling that and providing the fuel to complete the trip after a dip into Mars’ gravity well is even more difficult.
Given that, it’s no surprise that Obama’s speech last week named propulsion and radiation shielding as key areas research as it shifted NASA’s manned missions toward asteroids and Mars. Despite this shifted focus, Obama’s speech laid out no specifics as to what NASA’s Mars program was to look like beyond a date for landing some time in the mid-30s. I would advocate, with Lawrence Krauss, that we make our manned missions to Mars one-way trips with the maintenance of a permanent human presence on Mars in mind.
However, this decision borne of the serious technical challenges can mark the beginning of an even more ambitious long term project, which is where my view diverges from the one outlined by Krauss:
We might want to restrict the voyage to older astronauts, whose longevity is limited in any case. Here again, I have found a significant fraction of scientists older than 65 who would be willing to live out their remaining years on the red planet or elsewhere. With older scientists, there would be additional health complications, to be sure, but the necessary medical personnel and equipment would still probably be cheaper than designing a return mission.
My view is perhaps more controversial: I think we should send young astronauts to Mars. Not only do I think that the astronauts we send should be young rather than old, but I think that they should seek to raise families on the red planet. Rather than establishing a base on Mars dependent on the health of elderly explorers, we should seek to build a permanent colony that grows and develops over time.
Colonization of Mars would be the antithesis of the the Apollo approach. A human footprint on the surface of the red planet would be represent a first investment rather than the pinnacle of our Martian exploration. It would signify a firm promise not to cut ourselves away from the rest of the universe and would mark the first step in the noble goal of spreading terrestrial life beyond Earth’s shore.
Mars is the place to start our export of Earth’s seeds to the rest of the solar system and eventually beyond. While it goes without saying that the red planet lacks the amenities of Earth, it provides the most fertile ground for colonization of any body in the solar system outside of the Earth. It has an atmosphere that can provide shelter from cosmic radiation, there are clear signs of water without the barrier of strong surface charging, and it’s close enough to the Sun to allow for the growth of terrestrial plants, providing food and oxygen to Mars’ settlers.
Krauss ends his piece:
To boldly go where no one has gone before does not require coming home again.
Indeed. What it requires is that we seek out new homes for Earth’s explorers and their descendants.