Mars: Getting there

OPINION:

A lot of publicity has surfaced on how to set up colonies on the planet Mars. Recently, famed British cosmologist Stephen Hawking chimed in, demanding a “safe place” for humanity, as Earth becomes uninhabitable, in Mr. Hawkings’ fevered imagination.

But the chief purveyor of Martian colonies has been rocket engineer Elon Musk, developer of SpaceX rockets and the Tesla electric car. I think his Mars plan is entirely misconceived and much too complicated. His project requires a huge super-Saturn rocket, never tested or even designed. I rather suspect that building this largest rocket ever, with government money, of course, may intrigue Mr. Musk more than exploring the planet Mars as a base for human settlements.

The Mars system includes the planet, one-tenth the mass of the Earth, the New York City-sized moonlet Phobos, orbiting at a distance of 2.8 times Mars’ radius, the Manhattan-sized moonlet Deimos at 6.9 Martian radii, and perhaps even tinier moonlets yet to be discovered.

There is another aspect to this plan, which may be important. The average person regards the plan to fly hundreds to Mars as sheer “fantasy” — as do I — and the likely cost as astronomical (pun intended). This could turn off any “first steps” to land a human on Mars — thus creating a “Catch 22” dilemma.

A similar situation prevailed 70 years ago when popular articles portrayed Earth satellites mainly as venues for conferences and symposia — and at a time when we could barely put a few pounds of payload into Earth orbit. No wonder that serious advocates of unmanned Earth satellites for badly needed research could not get much attention — until 1957, and the launch of the Russian pioneer satellite Sputnik.

As I see it, getting people to land on the surface of Mars is only half the problem; getting them back is even tougher. Because of the planet’s gravity field, the takeoff rocket’s thrust has to be sufficient to overcome this gravitational force — i.e., the weight of the astronauts, samples of Mars rocks, structure, rocket and propellants needed to bring them back to Earth.

However, in orbit about Mars is the moonlet Phobos, which has nearly zero gravitational field. Using it as a base, and thence preparing for the journey to the home planet, greatly simplifies the return problem. We would no longer need to develop a super-Saturn rocket: We require only a longer burn time of a smaller rocket. In that sense, the operation resembles much more the Apollo Moon-mission than the plan proposed by Mr. Musk.

As a general rule, one should avoid the strong gravitational fields of planetary surfaces; it is much better to build (or use existing) operational bases in orbit, so that the basic Mars mission then becomes simply an Earth-orbit to Mars-orbit transfer.

For example, the Apollo project to the moon got it half right. If it had started from low Earth orbit instead of from Earth’s surface, we might not have needed the costly, specialized high-thrust Saturn rocket.

The moral of this story: Space missions should not be designed by rocket engineers but by those concerned with the aim of the mission. A good example is the “Ph.D. project,” whose purposes include learning the origin of Phobos-Deimos and the planetary development of Mars, its climate history and, of course, the search for Martian life.

Here one sets up a science lab on Deimos to study in detail samples from Mars’ surface sent by robotic rover vehicles. The mission includes a two-man sortie to Phobos, from there to the planet’s surface and back, before returning to Deimos, and thence back to Earth.

• S. Fred Singer is professor emeritus at the University of Virginia. He earlier served as founding director of the U.S. Weather Satellite Service and as chief scientist of the U.S. Department of Transportation.