[Gary Seven]

This article was published three years ago but there was something earlier in the media about the radiation hazards of space travel. And then there's that famous Jim Kirk quote

Cosmic rays may prevent long-haul space travel


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."

Journal reference: Radioactivity in the Environment (vol 7, p 894)

[Zardoz]

So no Fantasic Four anytime soon in real life then....

But seriously, great article!!!

[MissionTrek08]

We knew the job was dangerous when we took it! (bu-KHAA!)

But seriously, the article brings up one of the key reasons why sci-fi often must find a way to "shorten the trip" in space exploration: we've reached a barrier of sorts between our technology to either propel us or protect us in space travel, and the fragility and relative short live spans of our bodies.

Gimmicks like warp power and hyperspace travel greatly reduce both of these obstacles in our path. Probably the same reason so many of these stories emphasize shielding technology too -- not just for weapons defense but for occupant survival first and foremost. Humans simply can't live long enough to "get there" by driving the speed limit, and the long trip will harm you anyway. The dangers of cosmic radiation and the like would seem constants we can't change, so for us to reach interstellar potential, we'll have to devise methods to defeat prolonged exposure one way or the other.

It sure makes it look like tapping new energy sources and increasing efficiency in energy use is a priority we won't grow out of any time soon.

[FanWriter45]

Several of the ISS and Mir crews have been in orbit for the better part of a year. Have they been feeling any of these effects?

They assume that the entire ship would have to be sheilded. But, if the crew were to be in suspended animation, (something we're getting much closer to in the last few years) only their bodies would have to be covered, wouldn't they? The time the crew spent outside of such capsules would probably be no worse than what the crews of the ISS are experienceing today.

This sounds more like an engineering problem, than it is an insurmountable barrier.

[Zardoz]

I do know just about everyone that has been into space ends up with some psycological damage from knowing they'll never go back....

[FanWriter45]

On the History Channel's "Universe" program last night (Tues, April 8) they talked at length about efforts to colonize both the moon and Mars. The subject of radiation exposure was brought up, but according to those involved, the hazard really isn't that scary. Spacecraft would have to be built with "storm shelters" and we'd have to send some early warning system probes closer to the sun.

Background "cosmic radiation" simply isn't that bad, while the main danger seems to be from the charged particles blown out during a solar storm. Apparently, there are several ways of dealing with this, including storm shelters, pointing the bulk of the spacecraft's mass toward the sun and using it as a sheild, and possibly even generating a magnetic feild around the crew compartment. (Although the feild idea would require a lot of power.)

Several members of the ISS crews have been in orbit over 5 months. (about the same time it would take to get to Mars) The big problem it seems, is not radiation so much as the physiological problems brought on by prolonged weightlessness. Loss of bone density, and muscle mass. Before we go to Mars, we're going to have to look at spinning our ships for artificial gravity.

(Since "gravity plating" is still very much science fiction.)

[Zardoz]

Originally Posted by FanWriter45

On the History Channel's "Universe" program last night (Tues, April 8) they talked at length about efforts to colonize both the moon and Mars. The subject of radiation exposure was brought up, but according to those involved, the hazard really isn't that scary. Spacecraft would have to be built with "storm shelters" and we'd have to send some early warning system probes closer to the sun.

Background "cosmic radiation" simply isn't that bad, while the main danger seems to be from the charged particles blown out during a solar storm. Apparently, there are several ways of dealing with this, including storm shelters, pointing the bulk of the spacecraft's mass toward the sun and using it as a sheild, and possibly even generating a magnetic feild around the crew compartment. (Although the feild idea would require a lot of power.)

Several members of the ISS crews have been in orbit over 5 months. (about the same time it would take to get to Mars) The big problem it seems, is not radiation so much as the physiological problems brought on by prolonged weightlessness. Loss of bone density, and muscle mass. Before we go to Mars, we're going to have to look at spinning our ships for artificial gravity.

(Since "gravity plating" is still very much science fiction.)

Some great info again there FAN!! You and Gary seem ot keep up on that! I like Universe, but don't really have time for the shows I do resguarly watch to take on anothero ne.