Mars Direct, part 2

In my column last week, I discussed Mars Society President Robert Zubrin’s daring plan for putting humans on Mars in 10 years — an almost shockingly short time span when compared to the usual estimate of 20 or more.

Although I summarized the reasons why Zubrin argues that NASA should make Mars its next target and explained his rationale regarding a couple of logistical questions related to getting there, I didn’t dig into the fascinating issues surrounding the details of the mission itself. Let’s dig into them now.

If you’ve only heard his skeptics describe Zubrin’s plan, called Mars Direct, you could be forgiven for thinking he has put forth a plan that will a) consign astronauts to months of boredom on the Martian surface, b) expose astronauts to an unacceptable risk of cancer and c) rob the crew members of their strength due to lengthy exposure to zero-gravity conditions.

In other words, you could be forgiven for thinking Zubrin has made the wrong choice at almost every step of the way in the process of formulating his plan. And, if you accept the premises on which his assailants’ arguments are based, you would be right.

Among those premises are the following ideas: that extended stays in close quarters with a small group are inherently boring, that no risk of cancer is an acceptable risk of cancer and that zero-gravity conditions are unavoidable in interplanetary flight.

In the process of answering these criticisms, Zubrin deftly dismantles the premises that (unconvincingly) support them.

First, he disarms the concern that an 18-month stay on the Martian surface will induce unbearable boredom by noting that this is an assumption based on the experience of a small group of U.S. Navy sailors at a base in Antarctica — sailors who, he noted, were almost certainly wishing they were stationed in Hawaii or San Diego instead and who were not tasked with conducting research during their stay.

He contrasts this with the experience of crew members at the Flashline Mars Arctic Research Station on Canada’s Devon Island, where volunteers conduct simulated Mars missions and have found that overwork, not boredom, is their biggest problem — because everyone involved is highly motivated about his specific mission and, far from longing for a more temperate clime, has chosen to spend a month at 75 degrees north latitude.

Second, he points out that if NASA were to send a manned mission to Mars every other year (as he suggests), the crew members on the five missions would be exposed to the same dosage of solar radiation as are the members of the crew on the International Space Station in the same span. He further points out that this exposure would increase a typical non-smoking crew member’s risk of dying of a fatal cancer from 20 percent to 21 percent — something he expects won’t bother astronauts capable of being among the first humans ever to visit another planet.

Finally, he neutralizes the concern that the 12 total months of flight time in zero gravity will dangerously decondition the crew by showing why they won’t have to fly in zero gravity in the first place. This is because, per his plan, the crew’s habitat unit would be tethered, while in transit, to the spent upper stage of the rocket booster that powered its initial ascent, and both components would be rotated around a common axis in order to generate artificial gravity.

(During the stay on Mars, the planet’s gravity, which is three-eighths as strong as Earth’s, would be sufficient to keep the crew healthy.)

As an exposition of the Mars Direct plan as a whole, this survey only scratches the surface. But, as someone who is much more inclined toward the humanities than the sciences, I can attest that anyone interested in learning more about the plan should read Zubrin’s 1996 book “The Case for Mars,” as it conveys Zubrin’s ideas and explains the related scientific concepts in a way the proverbial “well-educated layman” can understand.

As Zubrin makes clear in his book, if we are serious about exploring and someday settling outer space, we should make Mars our target — and, at least so far, his plan is the best one around.


E-mail: jarlower@indiana.edu