Why humans should go to Mars and other places in space

Reusable, modular space systems could make human Mars missions more affordable and eliminate one long-running objection to them. (credit: J. Strickland)

In a recent op-ed published in the Richmond (Va.) Times-Dispatch, titled Why humans shouldnt go to Mars, University of Virginia biology professor Michael Menaker argues that human exploration of Mars doesnt make good sense. We are already exploring Mars with robotic spacecraft, he states, and there are urgent Earth-bound problems to solve.

However, he has not made his case, which is based on several wrong fundamental assumptions. Its possible he may be reacting to the blatant Mars Hype that was recently put out by some people within NASA who support the SLS and Orion programs, since the article does mention the Orion test launch. What the article really represents, however, is the zero sum game attitude by a few within the science community, some of whom depend on government science programs for their employment. I must emphasize that this point is not meant to denigrate the vast majority of scientists, many of whom work on valid and important research and struggle every year to maintain their labs financial survival. I suspect the majority of those who work on robotic spacecraft programs do strongly support the human space program, but those who do not sometimes get more media attention when they speak out, since taking such a position is controversial. Their attitude is that funding for a human Mars mission would take money away from their science. What Menaker forgets is that any human spaceflight program uses funding that could possibly go to the robotic or pure science programs instead, so that opposition to Mars programs is also in effect opposition to all human spaceflight. His comments later in the essay, about urgent Earth-bound problems, confirm that this is his position.

In my view, both robotic and human programs are both important and interdependent. The robotic program gets part of its support from interest in future human exploration, while that future human program will rely heavily on the data from the robotic programs to determine good landing sites and allow safe landings. As a very strong supporter of science in general, and space science and planetology in particular, I find it sad that some people have such a limited vision of how tightly linked science and exploration are. Professor Menaker works at the University of Virginia, whose first president was Thomas Jefferson. As US President, Jefferson sent the Lewis and Clark expedition across two-thirds of a continent and back. That expedition contributed tremendously to understanding the geography and biology of the American West. In like manner, future exploration of Mars by robots and humans will help us understand planets in general, even our own Earth. The exhortation by Menaker to stay home on the Earth would, if followed, greatly impede both our ability to understand the Earth and to protect it.

Menaker agonizes over the stress on crews on such long voyages, but these are nothing new, and in turn will contribute greatly to humanitys future. Previously, several nations, such as Portugal, Spain, and England, have sent crews of sailors on very long voyages of exploration, some lasting for three years, as long as a Mars expedition would last (just getting to Mars takes six to eight months.) The results of these voyages included finding an economical route to the Far East around Africa, proving yet again that the world was round by circumnavigation, and the discovery of Australia and the Hawaiian Islands. Furthermore, expeditions to Mars will be in constant contact with their families on Earth, even though there will be a time delay. The isolation and stress of a Mars mission will be nothing like such maritime crews withstood, in an age before good food and good health could be provided at sea.

Menakers take on the high cost of Mars expeditions and the risk to astronauts is also based on wrong and outdated assumptions. With current and past technology, as represented by the expendable SLS booster and Orion programs, the cost, the risk to crews, and the potential radiation doses would in fact be very high. If Mars missions were mounted using the current NASA plans, the cost would probably be in the hundreds of billions of dollars and radiation doses could exceed current lifetime safety limits. However, it is very unlikely that such huge amounts would ever be approved by Congress, and since just one of the unmanned programs, the James Webb Space Telescope, will cost almost $10 billion all by itself, complaining about only the current human space budget seems misplaced. It is also worth pointing outfor probably the millionth timethat the entire NASA budget is one half of one percent of the federal budget. All of the existing social programs vastly outspend it.

So it is much more likely that Mars expeditions will actually be conducted with reusable boosters and reusable spacecraft designed and built by private companies. Much of the space community is coming to share this view. In addition to reducing the cost, such boosters will allow the use of heavy and effective radiation shielding on the crew habitats, making the radiation issue moot. By the time we are ready for Mars expeditions, sometime after 2025, such boosters and spacecraft will be operating.

With these, a continuing program of Mars exploration will be possible within annual NASA budget limits. The cost of an initial human NASA Mars program would probably be in the tens of billions of dollars, but that is trivial compared to the vast sums spend on the inefficient shuttle program. The more that private companies are involved, the lower the cost will be. If the cost is shared by developing standardized vehicles to also support a lunar base, the overall cost will be lower still. In any case, total costs of a program are misleading, since it is the annual cost that is more important to an exploration program run by a government. Over a 15-year time framefive years for development and ten years for operationsthe cost of a $30-billion program would be roughly comparable to what is now being wasted on the SLS.

A program will also not run out of vehicles quickly if they are all designed for reuse, so the program can be continued at a lower cost. With a robust Mars mission architecture, the issue of whether crew members stay at Mars or come home after one expedition becomes moot. Since the vehicles that would take crew members to Mars are reusable, we would want them back at Earth to use for another expedition. This means at least some of the crew members would return after the first expedition was over. The high amounts of mass that a robust mission can land on the surface would allow other crew members to remain on Mars and augment the next crew to arrive, with food and supplies sufficient for many years. A larger crew would provide more hands to do work such as enlarging the base and its pressurized habitat volume. Thus a flexible policy on who returns and who stays could allow a larger crew to do useful work at a Mars science base with each succeeding mission.

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Why humans should go to Mars and other places in space