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

Why humans should go to Mars and other places in space

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In a recent op-ed published in the Richmond (Va.) Times-Dispatch, titled “Why humans shouldn’t go to Mars,” University of Virginia biology professor Michael Menaker argues that human exploration of Mars doesn’t “make good sense.” We are already exploring Mars with robotic spacecraft, he states, and “there are urgent Earth-bound problems to solve.”

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.

However, he has not made his case, which is based on several wrong fundamental assumptions. It’s 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 lab’s 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 humanity’s 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.

Menaker’s 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 out—for probably the millionth time—that 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.

Placing thriving human settlements on at least one world beyond the Earth would virtually guarantee human survival for the long term. Mars is the best place for such a settlement in our solar system.

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 frame—five years for development and ten years for operations—the 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.

With the ability to launch more duplicate spacecraft, with multiple levels of redundancy and spare parts, the risk to the crew greatly diminishes. To reduce problems with microgravity, it is also possible to connect two crew modules together with a cable and rotate them to provide artificial gravity during the transit to Mars. The planet’s gravity of 0.38g should enough to provide good exercise for crewmembers once they are on the surface.

Menaker worries about wasting money on Mars, which he claims could be used instead to help millions of people on Earth. Here he is mirroring the reactionary ideologies of the old Earth Firsters and other such groups, who create an artificial division in their minds between the Earth and the entire rest of the universe. If we should not go to Mars, maybe we should not be on Antarctica, or maybe we should never have even voyaged beyond Europe. Under that ideology, humans would never leave the Earth, and we would still be sitting here at the bottom of the gravity well when the “killer asteroid” finally hits us. The dinosaurs obviously had no space program when the Chicxulub impact occurred, wiping them out, but humans can have one.

Placing thriving human settlements on at least one world beyond the Earth would virtually guarantee human survival for the long term. Mars is the best place for such a settlement in our solar system. It the only other world with a solid surface and atmosphere at moderate temperatures where humans in space suits can walk around safely. This survival issue highlights the fact that science alone has been way overused my many as the primary rationale for all human space activities.

One of the fundamental rationales for landing humans on Mars is to begin to learn enough about the planet so that it can support not just “a few humans,” but eventually millions of people. When the first humans reached North America from Siberia, there were just a few of them. By the time Europeans arrived, over 15,000 years later, there were tens of millions of people living in North and South America, some of them in very inhospitable places, such as the high Arctic and harsh deserts. The skills and equipment that they used to survive and thrive in such places were high technology to them. Once nice thing about future Mars colonization is that, unlike the Americas, there are no existing inhabitants to displace.

By focusing first on creating an inexpensive and efficient system of space transportation and logistics, first in cislunar space and then extending to the inner solar system, we can maximize the effectiveness of what funding the program may get and also the creative engine of entrepreneurship.

In his discussion about Apollo, Menaker fails to understand why the effort was made and why the space program has to a large degree been directionless since then. The impetus for Apollo was national prestige, and for it to work, the US had to accomplish a hard task. Although Apollo did succeed in its valid goal of enhancing national prestige during the Cold War, the high cost of expendable rockets made it politically impossible to continue Apollo and has prevented us from being able to conduct serious space operations that need heavy equipment in space. As a result, serious space exploration beyond low Earth orbit has been delayed by 40 years. The option of building truly reusable rockets has been available ever since Apollo, but poor government decisions have effectively blocked that path. With the imminent advent of private reusable rockets, the government can no longer impede progress in that direction, either by accident or intent, opening the door to vastly cheaper human and robotic space operations.

The claim that robots can do as well as human explorers has probably been refuted dozens of times by many writers, including some of them who work in the planetary program. Yes, human exploration does cost more, but it can get scientific results hundreds of times faster than a robot, no matter how sophisticated. If we want to try and drill kilometers below the Martian surface to see if there is any life, it will take a large drilling rig. Ask an oil field worker if he thinks robots could run a big rig like the ones they operate.

Menaker focused on Mars since that is where the media attention was at the moment. However, there are many other valid goals to accomplish and destinations to reach in space, such as the Moon, asteroids, and space development. It is important to realize that there should not be a zero sum game mentality in the space community like there is in parts of the science community. By focusing first on creating an inexpensive and efficient system of space transportation and logistics, first in cislunar space and then extending to the inner solar system, we can maximize the effectiveness of what funding the program may get and also the creative engine of entrepreneurship. By creating a unified space exploration and development program that addresses space goals in an integrated way, and working closely with the private sector, we can create mining bases on the Moon, power satellites to help end global warming, a system to both detect and protect the Earth from potential asteroid impacts, and eventually create a human civilization spanning much of the solar system.