Humans in Space: Mars or the Moon?

The next great human achievement in space has only two practical alternatives: the moon, and Mars. Neither will be cheap, or easy to achieve. But which one?

Episode Summary:

In 1961, when United States was well behind the Soviet Union in the space race, then Pres. John F. Kennedy had a crazy idea: to land a man on the moon before the end of the 1960s. The success of the Apollo program in achieving that goal was an engineering achievement on par with the Manhattan Project and mass production, but despite much higher technology today, it will be a challenge to repeat that success. Jim Anderton explains why. 

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Transcript of this week’s show:

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If you are around in 1961, you probably remember then Pres. John F. Kennedy making a stunning announcement: NASA was instructed to land a man on the moon, and bring him safely back to Earth, before the end of the decade. Of course, hindsight is 20/20, and the spectacular success of the Apollo program papers over the audacity of Kennedy’s original plan. When he made that speech, the total NASA human spaceflight experience was 15 minutes, in a flea jump of a suborbital flight by Alan Shepard in the tiny Mercury capsule he called Freedom Seven. 

The Soviets were far ahead, having already orbited cosmonaut Yuri Gagarin using boosters that were far more powerful than the converted Redstone and Atlas military missiles used in America. The technology to send human beings to the moon simply didn’t exist. And by “didn’t exist”, I mean everything. Boosters, human-rated spacecraft, engines, guidance and navigation systems, life-support and communication systems to support a moon landing simply did not exist. 

In many cases, the materials, and manufacturing technologies to build those systems didn’t exist either. At that time, there were physicians that stated that human beings couldn’t survive the length of time of a moon voyage in weightlessness, and that radiation would kill anyone walking on the surface anyway. There were psychiatrists that claimed that the stress of the mission would be intolerable, and some engineers doubted that any spacecraft could have sufficient backup systems to make the risk worth it. Some scientists were worried that astronauts would bring back viruses or bacteria from the surface of the moon, infecting the earth. 

In the end, NASA sent nine crews to the moon, and 12 men walked on the surface. But that was it. After that stunning success, the agency set its sights on making orbital spaceflight routine, with the space shuttle program. Logically, the shuttle program probably should have preceded exploration of the moon, and likely would’ve made the process safer and cheaper. And while a brilliant engineering success, the shuttle program never delivered the order of magnitude reduction in cost per pound to orbit that the system promised in the early 70s. 

But it worked, and because of it, the international space station was built, and it so far has proved that humans can endure 0G conditions for periods of half a year with no permanent ill effects. That’s good, because the next step in crewed spaceflight is going to involve long-duration missions, which, with current propulsion technology, can have only two practical destinations: the moon, and Mars. Mars has been the dream of astronomers and rocket builders for over a century, and the engineering challenges of sending a crew there make Apollo look like the Stone Age. It will also be ruinously expensive, and it’s far from clear that even Elon Musk can achieve this, even with his very large Starship rocket program. 

The moon however is very achievable, and at this point, it is likely more desirable anyway. It’s reachable, at ¼ million miles distant, and recent probes suggest that there is water on the surface, which could be used for oxygen and hydrogen rocket fuel, and there are resources that can be exploited to build bases there. But perhaps the most interesting resource waiting to be extracted from that moon is helium-3. This isotope has a very interesting property: used in a fusion reactor, it should produce power aneutronically, meaning without the long-lived radioactive waste we associate with nuclear power. Nuclear power without nuclear waste. That alone should make a moon base a practical proposition, except for the small detail that it’s necessary to process thousands of tons of lunar surface regolith make useful quantities of helium-3. 

But just as fundamentally, no one is asking a more basic question: given the fragility of the human body and the dramatic improvements in AI and robotics, why send people at all? Robots were sent to the moon before Armstrong and Aldrin landed there, and soon, there will be sample return missions from Mars. Samples from asteroids have already been returned by robotic probes. It’s a given that machines are far cheaper than crewed spacecraft, which means more science for every dollar. 

But the machines lack the drama of humans in space. The new James Webb space telescope is engineering achievement on the order of Apollo. Like Hubble before it, it will likely do more to reveal secrets the universe that all the ground-based telescopes in human history, and might even be used to detect planets that may harbour alien life. But is that enough? The current technology, we could build self driving race cars and run them at Indianapolis. But when would anybody watch?

Written by

James Anderton

Jim Anderton is the Director of Content for ENGINEERING.com. Mr. Anderton was formerly editor of Canadian Metalworking Magazine and has contributed to a wide range of print and on-line publications, including Design Engineering, Canadian Plastics, Service Station and Garage Management, Autovision, and the National Post. He also brings prior industry experience in quality and part design for a Tier One automotive supplier.