Dennis Tito's mission to Mars: Martian dreams | The Economist

HOW times change. In 1952 Wernher von Braun, the ex-Nazi rocket engineer recruited by the Americans after the second world war, published a book called “The Mars Project”. In it, he detailed his plans for the human exploration of Mars. Ten ships, assembled in Earth orbit, would burn 5m tonnes of rocket fuel carrying a crew of 70 to the planet. On arrival, ground crawlers would carry the crew from their polar landing site to the equator, where a permanent base would be built. You can only imagine the price-tag for such a project, but suffice to say that only a superpower could have even dreamed of paying for it.

Six decades later, on February 27th, Dennis Tito, an American investment manager and space enthusiast who, in 2001, became the world’s first space tourist, unveiled his own plan. Inspiration Mars is a more modest affair. If all goes to plan, in January 2018 a single, small spaceship, carrying two crew members, will blast off for a 501-day trip to Mars and back. If it arrives safely, there are no plans to land. Instead, the idea is merely to fly around the planet and then head back to Earth. Unlike von Braun’s project, little government involvement will be necessary. Mr Tito hopes to pay for Inspiration Mars with a mix of his own money, donations from the public and the sale of media rights.

That is not to say that Mr Tito’s plan is timid. On the contrary: it is eye-wateringly (or, as one colleague puts it, “bowel-looseningly”) bold. Although endless studies have been done on how it might be possible to ferry humans to Mars, no one has ever attempted it. Mr Tito’s launch date is fixed, for it is designed to take advantage of a rare period of orbital proximity between Mars and Earth. If he misses his deadline, another opportunity will not present itself until 2031. That gives the team just under five years to design the mission, specify a spacecraft, find a rocket to launch it on, select a crew and carry out all the necessary checks and double-checks. And, without the financial muscle of a nation-state behind him, all this must be done on a budget.

Mr Tito’s press conference was, understandably, rather short on technical details. But a few did emerge. There will be only two crew members, for instance—a husband and wife, both middle aged. The hope is that choosing a married couple will keep any interpersonal friction to a minimum during a year and a half spent inside a craft no bigger than a motor home (though some spouses would surely challenge this logic). Picking astronauts in their 40s or 50s, meanwhile, will lessen the impact of the large radiation dose that both can expect to absorb (radiation, of course, being potentially damaging to fertility). To keep costs down, and to avoid relying on new (and therefore untested) technology, the mission will, wherever possible, recycle technology that is already in use on the International Space Station.

Still, there is a host of unresolved questions. Radiation is one. Data from existing probes suggest that, although the crew will accumulate a significant dose, the radiation levels in interplanetary space should not be fatal. But a mission with a flight time of a year and a half risks encountering the much fiercer radiation generated by coronal mass ejections, unpredictable events in which the sun blasts huge quantities of plasma into space. Exposure to such a radiation storm could be lethal. There is, as yet, no generally agreed-upon way of protecting a crew from its effects. The sun ought to be in a relatively quiet part of its 11-to-14 year cycle by the time the mission launches, but that merely reduces the risk—it does not eliminate it.

The return leg of the trip poses problems of its own. To keep fuel use (and therefore mass) to a minimum, the spacecraft will be on a so-called “free return” trajectory, in which the mission planners rely entirely on gravity to guide their craft through space. That means that, by the time the crew return to Earth in 2020, they will hit the atmosphere at speeds in the region of 51,000kph, smashing the re-entry speed record held by the Apollo crews. It is not clear whether any existing heat-shield technology could protect them. Mr Tito said he was working with NASA to investigate the problem.

America’s space agency, of course, has plans (at least in theory) for a crewed Mars mission of its own, due to fly sometime in the 2030s. Taber Macallum, one of Mr Tito’s engineers, was keen to emphasise that he was not trying to steal the agency’s thunder: “We’re not competing with them. We’re trying to be a useful stepping stone.” But Mr Tito has joined a growing list of people and organisations interested in sending people to Mars: besides himself and NASA, there is interest from Elon Musk, the founder of SpaceX, a private rocketry firm. The Chinese have hinted at one day mounting a mission, too, though details are scant. And other non-profit foundations are interested, such as Mars One, a Dutch group that has been advertising for volunteers for a one-way trip, whose crew would end up stranded on Mars, although it has nevertheless received plenty of applicants.

All this interest implies that sending people to Mars is merely a matter of political will and a bit of ingenious engineering. It is not. It is extremely difficult and dangerous, a fact that Mr Tito mentioned repeatedly in his press conference. When planning the Apollo moon missions, NASA devoted a significant chunk of time to figuring out how to get a troubled spacecraft back to Earth, studies that proved their worth in the narrowly averted disaster that was Apollo 13. The crew of a Mars mission, though, would be vastly further away, and beyond any Earthly help should anything go wrong. Even assuming Mr Tito can get his mission into space—which seems a long shot in itself—it is by no means guaranteed that it could return its crew safely to the Earth. Only daredevils need apply.

Correction: We originally said that Mars One's project was a "suicide mission". Although volunteers are expected to die on Mars, it will be of natural causes, so the description was not accurate. Sorry.