When do you think humans will set foot on Mars?

The pessimist in me finds it very hard to believe that this will ever happen. It seems we are in an age when we need very good reasons why we should be doing anything, as though the need for space travel can be discovered through logical discourse. For Mars, no country has yet found a reason for going there that can be supported politically or economically. When you tell a politician that we need to go to Mars to simply explore its mysteries and search for fossils, or to continue the great human exploration of new frontiers, they look at you blankly and ask 'Yes that's true but you need a better reason'. Plus, there are some very serious technological and medical problems. No one has figured out how to insure that the astronauts will be strong enough to make it to Mars and back without severely destroying their bones, experiencing radiation sickness, and suffering a range of serious physiological factors.

In just 300 days, the effects are serious enough that Russian astronauts from the Mir space station are barely able to return to Earth because of their compromised medical conditions. To get to Mars requires a journey of over 500 days round trip, and probably a 700+ day stay on the planet with its very low gravity. Psychologically, it is now known that the profiles of the individuals that will do best living in cramped quarters for over two years are NOT those of any member of the current astronaut corps. One thing is certain, if we do attempt such a journey in the 21st century, we will make the voyage only when Mars is closest to Earth at 'opposition'. Also, we will make the trip at a time that minimizes the astronaut’s risk for solar radiation and cosmic ray exposure.

We know when the Mars oppositions will be, and we can estimate the 21st century solar cycle. The earliest opportunity would be 2035 when the flare and cosmic ray effects are about comparable. To delay our landing beyond 2035, we may have to wait until 2065 as our last chance. After then, either the cosmic ray or flare conditions may prove unacceptable for making the attempt in the rest of this century.

This answer was updated in 2011. See my books: The Astronomy Cafe (1998) and Back to the Astronomy Cafe (2003) for more FAQs in printed form. Author: Dr. Sten Odenwald, Copyright 2011

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