Those cosmic rays can mess you up!
Posted on 08/01/2005 1:19:26 PM PDT by LibWhacker
The radiation encountered on a journey to Mars and back could well kill space travellers, experts have warned. Astronauts would be bombarded by so much cosmic radiation that one in 10 of them could die from cancer.
The crew of any mission to Mars would also suffer increased risks of eye cataracts, loss of fertility and genetic defects in their children, according to a study by the US Federal Aviation Administration (FAA).
Cosmic rays, which come from outer space and solar flares, are now regarded as a potential limiting factor for space travel. "I do not see how the problem of this hostile radiation environment can be easily overcome in the future," says Keran O'Brien, a space physicist from Northern Arizona University, US.
"A massive spacecraft built on the moon might possibly be constructed so that the shielding would reduce the radiation hazard," he told New Scientist. But even so he reckons that humans will be unable to travel more than 75 million kilometres (47 million miles) on a space mission – about half the distance from the Earth to the Sun. This allowance might get them to Mars or Venus, but not to Jupiter or Saturn.
Risky business
Helped by O'Brien, the FAA's Civil Aerospace Medical Institute in Oklahoma City investigated the radiation doses likely to be received by people on a 2.7-year return trip to Mars, including a stay of more than a year on the planet. The study estimated that individual doses would end up being very high, at 2.26 sieverts.
This is enough to give 10% of men and 17% of women aged between 25 and
34 lethal cancers later in their lives, it concludes. The risks are much higher than the 3% maximum recommended for astronauts throughout their careers by the US National Council on Radiation Protection and Measurements.
The risks are smaller for older people because cancers have less time to develop. But women are always in more danger than men because they live longer and are more susceptible to breast and ovarian cancers.
The study warns that cosmic rays would also increase the risk of cataracts clouding the eyes. Furthermore, men exposed to a solar flare might suffer a temporary reduction in fertility, and the chances that any children conceived by travellers to Mars will have genetic defects are put at around 1%.
Serious brain damage
The study's lead author, the FAA's Wallace Friedberg, highlights other work suggesting that heavy nuclei in cosmic radiation cause "serious brain damage" in mice, leading to memory loss. "Heavy nuclei exposure must be a serious consideration for space missions such as a trip to Mars," he says.
Improving spaceships' shielding by using water, hydrogen or plastics can protect astronauts to some extent. But this is limited by the constrictions of craft weight and design, Friedberg points out.
"Increased speed would also reduce radiation exposure" by reducing journey times, he notes. "And drugs or food supplements that can reverse radiation damage are being considered."
Others suggest more radical solutions might be needed. "Radiation exposure is certainly one of the major problems facing future interplanetary space travellers," says Murdoch Baxter, founding editor of the Journal of Environmental Radioactivity. "Unless we can develop instantaneous time and space transfer technologies like Dr Who’s TARDIS."
No. This is a real problem. Especially at relativistic speeds.
Then let's make sure no one asks your opinion on how to overcome this.
Yeah, but they get to go to Mars. I think you could find volunteers even if you could GARAUNTEE that all those things would happen if you promise that they get to go to Mars.
It's not like they would be dropping like flies during the journey. Flying to Mars still sounds safer than climbing Everest.
You know, I wonder whether running a magnetic field around the ship would serve to sheild the crew the way the earth's magnetic field sheilds us--and how much power would be needed to create an effective sheild.
Well, the really heavy radiation-protected spaceship does not have to land, and could remain high in a barely captive orbit. Apollo-like light module could be used for the landings.
"Unless we can develop instantaneous time and space transfer technologies like Dr Who’s TARDIS."
IIRC, the TARDIS doesn't actually move. It exists "outside" space and time, and when you travel from one point to another it simply pulls its entrance out of the time and space you entered, and pushes it back in at the point you wished to travel to. That's why the TARDIS can be as large as you want without worries over how you move such a large mass from one point to another.
The "new" scientist should forget the "old" spelling. We aren't in England anymore (and the article refers to the U.S.), so it's spelled "traveler" with one "l". Spell checking aint what it used to be.
That said, I also find issue with their conclusion that cosmic rays kill you. They merely mutate your DNA and transform you into the first thing you mention or try to do after you get back.
TS
Agree it'll be a problem when we can travel at relativistic speeds. But to go to Mars, RA? Nothing a few inches of steel plate won't fix.
BS! Isn't this what shielding is for?
Probably so for the first wave of explorers. It would, however, make any kind of long term presence there problematic. You certainly couldn't put a self-sustaining colony on Mars with that rate of birth defects, for example.
What about the international space stateion? Some of those astronauts are there for significant durations. Does proximity to Earth shield them from cosmic rays to any extent?
Bring back Orion!
LOL!
Beat me to it!!
To the author of this piece:
>But women ... are more susceptible to breast and ovarian cancers.
Duh.
What will the astronauts do?
They will need shielding. Maybe a lot.
I think that approach is under much study. It's another proposed solution that sounds real promising to me.
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