Continuing from last week, here's more on why I think talk of exploring and colonizing Mars is a boondoggle at this stage.
Water is going to be a Big Deal. Actually, obtaining liquid water on Mars will be a snap compared to the moon, where it's been compared to extracting moisture from concrete. But it's still going to be a huge challenge, both to extract it from Mars' permafrost and to purify it. From experience on the International Space Station, we know that humans need about a gallon of water a day, which doesn't include water needed to grow crops in greenhouses. (Mars' atmosphere is too thin and too low on nitrogen to support plants on the surface.)
Martian soil is rife with toxic salt compounds known as perchlorates that will pose a daily danger to anyone living there. According to Mars expert Chris McKay, who has been studying Mars for nearly 40 years at NASA-Ames, if Mars were Earth, the whole planet would be a superfund site.
It's cold on Mars! How cold? Average temperatures are around minus 81 F but it can go down to minus 285 F. Keeping our valiant Mars explorers from freezing to death (in minutes, if they're exposed to the atmosphere) will be an ongoing challenge.
I try to keep up with the latest research but I rarely hear about Martian dust. The 24 Apollo astronauts hated the stuff during their brief stays on the moon, since it got into and on everything, including their skin when they took off their spacesuits in the capsules. After three lunar excursions, the suits Gene Cernan and Harrison Schmitt, the last two men on the moon, had been abraded by the sharp lunar dust to the point where a fourth excursion wouldn't have been safe.
The situation will be similar on Mars, except there the dust is blown around in the thin atmosphere (but not like in the movie The Martian — a 60 mph gale would feel like a light breeze). Every five years or so, the entire planet is covered in dust storms, but milder storms occur regularly. Dust will affect the integrity of airlock seals, it'll cover solar panels (the Opportunity and Spirit rovers both suffered from this problem), it'll get into machinery, and it'll and abrade anything it meets.
What about inevitable emergencies? At minimum, the crew should include at least one medically trained crew member (more than one, in case that one needed attention). One-way communication between Mars and Earth takes between 5 and 20 minutes (depending on where the planets are in their orbits), so they'll probably have to deal with extraordinary situations without help from mission control.
Returning to Earth. After nearly three years of living in zero gravity and Mars' 38 percent Earth gravity, our crew will return to Earth, assuming they haven't murdered each other under the extreme stresses they'd be dealing with. Bone loss, vision problems, and heart and circulation issues await them. There's an obvious antidote to this, one that NASA has officially kept off the table: One-way missions. Fill the crew slots with pioneers who are eager and willing to spend the rest of their lives on Mars, and many of the problems I've touched on above are surmountable. The possibility of getting a lethal dose of radiation, for instance, is a manageable risk, since they've already made their peace with dying on Mars. (Ain't gonna happen. We bring 'em back alive, whether it's a NASA or SpaceX mission.)
Any of the above issues could be a showstopper, plus any number unanticipated ones. If you'd asked me a few years ago in my Mars-believer phase, I'd have minimized the hazards. Now, sadder and wiser, I'm a Mars skeptic.
Barry Evans (he/him, barryevans9@yahoo) loves the planet on which he finds himself.