Radiation sickness. Brittle bones. Alzheimers. None of these will deter explorers in their quest to establish a foothold on Mars, says Apollo 11 hero Buzz Aldrin.
"Most people will say the big problem is going to be radiation," he told News Corp.
"I don't think we really understand how much we can take of that, or from how much we can be protected in efficient ways.
"But to hold astronauts to the same (safety) standards as those on the Earth is limiting. My thought is my grandfather, my great grandfather, their life expectancy was 60. Maybe less. It's better now. I'm 86!"
Buzz Aldrin spoke to News Corp while in Australia to promote his passion for a human outpost on Mars as part of the National Geographic's series of public talks, Mars: The Live Experience.
Would Buzz be happy to take such a risk himself?
"Well, it may hurt! But to have a very challenging life from age 40 when you get to Mars, and returning at 60, may be worth it having sacrificed for your country, or for humanity ... This is a concept that I don't think very many people have come to grips with yet."
Aldrin is no stranger to risk: He was a veteran combat pilot before becoming something of a first for the space program.
"Eisenhower said he didn't want to send poets, he didn't want to send philosophers - the idea of a journalist, no we're not ready for that. Teachers? No we're not ready for that either. He wanted success. And that's why the edict was test pilots. I thought I was too little, too late ... "
But his ground-breaking work on orbital trajectories while studying at MIT soon convinced NASA he had the right stuff.
Getting to Mars is an immensely more difficult proposition than the Moon. At every level.
"Then we didn't know," Aldrin said of early Mars plans.
"In '69, the same year as our mission, there was a study group called the Space Task Group. They came up with three levels of funding intensity. The highest level would have gotten to Mars before 1985. The less intense, 1990. Even the sparse funding would have got us there before the year 2000. Quite an optimistic prediction ..."
Moon shots have a degree of safety and efficiency built into them. Craft can enter a free-return orbit, where the Moon's own gravity slingshots the crew back towards the Earth.
"The punch line to that is, when we go to Mars, six months, seven months, eight months later - whatever it is - there is no free return," he said.
There is a narrow launch window where the trajectory and thrust have to be exact. Little more than half of the Mars missions so far have succeeded.
"You have to get it 100 per cent: 95 per cent, you don't get to Mars. You don't come back," he says.
"No free return and no backup system, no alternate. I'm disturbed about that."
Aldrin says independent, short stay missions would be doomed to fail.
"Probably the third time we get there, Congress or somebody will say 'here, we know how to do that - lets spend that money over here ...' And that will be it for Mars."
Aldrin says we have to occupy the red planet. His ambition is for a research station regularly cycling its crews, but always with somebody there.
Aldrin believes risks can be mitigated by sending mission components separately and cyclically, injecting a level of redundancy and fallback options into the process.
The perpetual cycle of incoming and outgoing crews, supplies and samples must be timed to make use of optimal Earth-Mars alignments.
"You can have a year-and-a half tour of duty, a five year tour of duty, a seven-and-a-half ... and come back," he says. "You're sending as many as you're bringing back.
Is Buzz disappointed he never got to go to Mars?
"No. See, we'd already flown," he says.
"The three of us (from Apollo 11) felt that being so fortunate to have come out with the mission and end up the first landing that we didn't feel like flying another mission was fair to other guys. We'd be taking a potential mission away from them."
Mars premieres Sunday 13 November at 9.30pm (NZDT) on National Geographic.
The accompanying book Mars: Our Future on the Red Planet by Leonard David is published by National Geographic Partners. Price is $49.99 hardback.