Dr. Louis Friedman, one of the co-founders of the Planetary Society, is coming out with a new book, “Human Spaceflight: From Mars to the Stars,” an excerpt of which was published on Friday in Scientific America. Friedman revives and revises a version of the humans vs. robots controversy that has roiled through aerospace circles for decades. Unlike previous advocates of restricting space travel to robots, such as Robert Park and the late James Van Allen, Friedman admits that humans are going to Mars to settle. But there, human space travel will end. Only robots will ever venture further.
His thesis is based at once on an optimistic view of advances in robotic technology and a pessimistic one of advances in technology that will enable human spaceflight. Friedman certainly thinks that interstellar travel by humans is impossible, because the distances are so vast, but does not offer a concrete reason as to why.
“The point of playing with these unimaginable numbers is to illustrate that interstellar travel is a subject of science fiction, not ready for prime time—at least not for humans. Most of the serious technical work for traveling between the stars, some with brilliant engineering and sophisticated applications of physics, relies on schemes that are entirely fictitious—or at least not real in any practical sense.”
The ghost of Arthur C. Clarke, were he to appear from whatever afterlife he may exist in, would remind us of one of his most famous maxims. “When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.” Friedman, it should be noted, is a rocket scientist who is both distinguished and, being in his 70s, elderly. In any case, one doubts that the folks at NASA’s Eagleworks Lab working on advanced propulsion designs for future star ships are going to close up shop because Dr. Friedman has told them they are wasting their time.
Friedman also does not open his mind why people won’t go to the asteroid belt or the moons of the outer planets. He does have an interesting vision of virtual space exploration. “I am convinced that the long-range future of humankind is to extend its presence in the universe virtually—with robotic emissaries, bio-engineered payloads, and artificial intelligence. Payloads will be designed for information processing, not life support.”
So, why does this method not apply to Mars? Friedman proves himself to be just a tad more enlightened than his curmudgeonly predecessors in the anti-human space travel community.
“But does that conclusion doom us to be couch potatoes—staying at home forever, confined by the limits of our planet? This is neither culturally nor physically acceptable. Culturally, we remain wanderers and explorers. Physically, the survival of our species requires humankind to become a multi-planet species. We cannot put all our eggs in our Earthly basket. It has too many forces that might cause it to fray—forces such as asteroid impact, large-scale conflict and war, pandemics, global climate change, and other types of environmental destruction, such as resource depletion and scarcity.
“To become a multi-planet species, we humans must reach Mars, because it is the only place we can reach. As arid, frozen, and desolate as it may be, Mars is the only known world besides our own that could be considered remotely habitable for humans. Indeed, it may have been much more habitable in the past, and life may have originated there as fast as it did on Earth and even have spread here from there, or there from here. Therefore Mars remains a human destination. It is the laboratory in which the evolution of the human species will be tested and, ultimately, determined.”
Friedman thus shares, at least to some extent, the vision of people like Robert Zubrin of Mars as the next frontier and the eventual home of a new branch of civilization. But he also seems to be somewhat like Sir Richard van der Riet Wooley, the Astronomer Royal, who, as late as 1956, was maintaining that spaceflight was “utter bilge.” Sir Richard lived to see the Apollo moon landings and the first flights of the space shuttle. To be fair, he was arguing about the amount of money that developing space flight would require and not its physical impossibility.
Friedman is not likely to live long enough to know that he will be proven wrong, which will be about the time that the first interstellar spacecraft with a human crew leaves the solar system. Whether the first star ship from Earth flies slower than light, traveling at relativistic speeds, or will warp space, as a group of NASA engineers believe to be possible, to achieve faster than light speeds, remains to be seen. In any case, Friedman joins a long line of experts who have declared something to be impossible, only to have made a grievous error.