Seems to me a Lead coating (inside the walls and pull-down over the windows) would stop 100% of harmful rays? Or am I mistaken? Any scientists out there?
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."
Seems to me a Lead coating (inside the walls and pull-down over the windows) would stop 100% of harmful rays? Or am I mistaken? Any scientists out there?
Sheesh! Just fly at night! Problem solved! ;^)
Lead would work very well as radiation sheilding, without a doubt.
Now figure out how to loft enough of it into orbit - that's the issue.
Fly to Saturn inside an MRI machine... fun.
Especially the ovarian cancers. I think.
Now we just need to better understand the processes that cause atrophy and bone loss in zero-G so we can come up with medications to counteract them, and a reliable nuclear drive, and we're all set.
They definitely have no vision or aspirations of any kind for the human race -- except wanting each family to scratch out a primitive existence from the land.
Cosmic rays woulds require yards of lead.
Just one more reason why I prefer time travel.
The ISS is in a low enough orbit that it is protected by the Earth's magnetic field.
Considering the amount of mass they would need for a substantial space program, they ought to get the material from bodies already in space. Moon mining, asteroid mining, that kind of thing.
That approach would work on charged particles, but not on neutral ones. Not sure of the exact compostition of "comic rays' but I bet some of the heavy particals are not charged. Otherwise the solution would be exactly as you suggest and too simple to be over looked by the author of this piece.
"BS! Isn't this what shielding is for?"
One would think so.
> Seems to me a Lead coating (inside the walls and pull-down over the windows) would stop 100% of harmful rays? Or am I mistaken?
You are mistaken. Have you considered how *thick* the lead would have to be... and what effect that mass hit would take on the vehicle?
Lead is not PC
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...
The risks are smaller for older people because they grow less new cells. Cells that produce new cells (bone marrow, embryos) are the most susceptible. Nerve cells are almost immune to low level radiation. Women are in more danger, not because of longevity, but because of more new cell production (ovaries, mammaries).
The drinking water used for the mission, if placed around the perimeter of the ship, could reduce neutron radiation exposure. Dense materials (like lead) would have to be used to shield the astronauts from gamma/cosmic radiation. It would be quite expensive to put enough shielding into orbit and then install it on the ship. Not impossible though.
I always thought that heat dissipation would be another significant problem. Any comments?
> I wonder whether running a magnetic field around the ship would serve to sheild the crew
Would help with electrons and protons, but won't do diddly-squat against gamma rays and neutrons, which are the dangerous ones anyway.
Uh ooh, I think we're stuck here for a while. Can't we all just get along?
The logistics of space travel, the distances, time, food, water, engergy are kind of a problem. That's why I don't believe the UFO nuts, earnest though they be.
Question: Since everything on Earth existed since the creation, though some things have changed form, have the space probes that have left Earth's orbit actually changed the planet or are they so infinitesimally small as to make no difference?
Use gold and platinum. By the time they get it launched the original cost of the material wouldn't matter.
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