Marshall works on astronauts' radiation shield

The Birmingham News ^ | 16 Jan 2004 | Kent Faulk

[demlosers]

HUNTSVILLE - Scientists at the Marshall Space Flight Center are working on a key problem of sending people on long-term trips into space - protecting them from dangerous doses of radiation.

When President Bush announced a new quest to go back to the moon and eventually on to Mars, he noted the dangers space-travelers will face.

"The environment of space is hostile to human beings," Bush said. "Radiation and weightlessness pose dangers to human health, and we have much to learn about their long-term effects before human crews can venture through the vast voids of space for months at a time."

NASA has worked for years on protecting astronauts from radiation. But Administrator Sean O'Keefe said Wednesday that understanding how the human body responds to long periods in space, and how to mitigate the effects, will become the agency's top research priority, especially at the International Space Station.

"We're reordering ... the very specific emphasis on the research on station to emphasize life science, human physiology, (and) the human effects and consequence of long-duration space flight," O'Keefe said. "This will become the primary, almost singular focus of our research agenda in the time ahead."

The space agency decided about a year ago to focus its radiation-protection efforts through a program based at Marshall.

"We're looking for innovative materials sources to protect the astronauts from damaging radiation" said Ed Semmes, program manager of the Space Radiation Shielding Program, which was created in February 2003. Scientists at other NASA centers, the Department of Energy and universities around the country are involved in the research.

Last fall, NASA commissioned the $34 million Space Radiation Laboratory at the Department of Energy's Brookhaven National Laboratory in Upton, N.Y. The lab is designed to simulate the radiation astronauts encounter in space.

The first material produced by the Space Radiation Shielding Program and tested at the lab was reinforced polyethylene, developed by Marshall scientist Raj Kaul.

Water is a good shield against radiation, and scientists have been using it as a benchmark for the level of protection they are seeking in new materials, Semmes said. Tests show that reinforced polyethylene "behaves very closely to what water does," he said.

Reinforced polyethylene eventually could replace the traditional aluminum skin of spacecraft, Semmes said. "It's about 10 times stronger than aluminum per unit weight," he said.

Because of its strength, reinforced polyethylene also could help in protecting the spacecraft from strikes by small meteoroids, Semmes said. Material that can serve multiple purposes is a key for long-duration missions, Semmes said, because fewer protective layers means less weight.

Spacecraft such as the International Space Station traditionally have been made of aluminum covered with insulation and shields to protect them from meteoroids and other debris.

Other research in the Space Radiation Shielding Program includes work at NASA's Langley Research Center on a radiation shield of foam between two panels of lightweight composite material, Semmes said.

The shielding program is working toward developing a suite of materials by 2008 and a tool for assessing their effectiveness in various circumstances, Semmes said. An informal goal is to deliver a new material every year, he said.

"We would hope to have four to six material design solutions by the time we get to 2008," he said.

The Space Radiation Shielding Program started with an annual budget of $4 million, Semmes said. It will get roughly $6 million this year and level out at around $7 million next year.

A six-month stay on the space station exposes the crew to the equivalent about 600 chest X-rays, more or less depending on how active the sun is during that period, Semmes said.

An astronaut on a mission of several months or more outside Earth's protective magnetic field and ionosphere would face dangerous doses of radiation without protection, Semmes said. "For travel beyond the station, the crew will be exposed to the full intensity of galactic cosmic rays, potentially resulting in the damage to cell tissue and altering genetics, leading to disease such as cancer," he said.

The Space Radiation Shielding Program was started as part of NASA's Space Radiation Initiative. A goal of that initiative is to ensure crews can staff the space station for up to three six-month missions or eventually a 1,000-day mission beyond Earth's orbit without going over radiation exposure limits recommended by the National Council for Radiation Production, according to a NASA press release.

Astronauts who walked on the Moon about 35 years ago didn't face the radiation problem because their missions lasted only a few days, Semmes said. "They just weren't out there long enough to get the exposure," he said.

[ambrose]

Okay...

Here's one thought about the issue of getting astronauts safely back to Earth.

Don't bother...

Let's get some hearty souls are willing to colonize Mars from the get go. Prepare the appropriate equipment, and send them off to arrive in six months. Simultaneously send out numerous other rocket ships containing food, water, vehicle to drive on Mars, equipment to build shelters, etc.

Then we send out supplies as needed.

Is this idea unworkable? If so, why?

[Triple Word Score]

It sounds like a great starting philosophy.

I am writing to my legislators urging them to get the government selling Space Bonds. I want to invest in this. I believe the human race can get fabulously wealthy by expanding (it always has!) and I want to put my money where my mouth is.

And this would let all the weenies who want to stay "safe" on earth opt out. (Like it's safe to keep all your assets in one place!)

[ambrose]

I guess my last point is we're spending too much time obsessing with astronaut safety. The astronauts should know ahead of time that they're volunteering for an extremely risky exploration enterprise for the betterment of all mankind.

Enough with the school teachers and 80 year-old senators!

We need people who will knowingly put their lives on the line to advance our knowledge of the solar system. We will advance by leaps and bounds once we engage in space travel with this basic understanding.

[ambrose]

I love the idea of space bonds. Also see my no. 4.

[Squantos]

I like it !

[Triple Word Score]

Well, it's nice to finish the trip with some bone mass. You could probably get by with less on Mars than you need here. Still, I'm squeamish about that bones-so-weak-your-muscles-pull-them-apart thing.

But I think centrifuge exercise is a good start on that, and that's something every SF reader is well-familiar with. We can do it--it's 14000 BC technology with some good gaskets thrown in. ;-)

The pioneers who crossed the Great Plains often did it barefoot with a handcart at best, and they buried many loved ones on the way. We're their heirs. We owe them a bit more courage than we show.

I think we're afraid of the wrong things!

[LPM1888]

Okay...

Here's one thought about the issue of getting astronauts safely back to Earth.

Don't bother...

Let's get some hearty souls are willing to colonize Mars from the get go. Prepare the appropriate equipment, and send them off to arrive in six months. Simultaneously send out numerous other rocket ships containing food, water, vehicle to drive on Mars, equipment to build shelters, etc.

Then we send out supplies as needed.

Is this idea unworkable? If so, why?

I volunteer to go!!

[Triple Word Score]

I'd go and I'd take my kids and cats with me. That's what pioneers DO!

The dog, though--I'd have to find a home for her.

[BenLurkin]

[Old Student]

Yeah, and what the heck is wrong with school teachers? Or 80-year-old Senators, for that matter? :)

I'm in my late forties, I'll likely be 50 by the time I finish my degree program, and I'd go to Mars in a heartbeat! I started high school in the fall of 1969, and I spent the best part of the summer glued to my B&W TV. By the time we get something put together for a Mars trip, I'm likely to be way over 80. I'd go to the Moon now, if I could get a ticket. Save the young guys for Jupiter and Saturn and beyond!

[ambrose]

I don't see how that's a problem. Russia had cosmonauts on the Mir for nearly two years. Sure they were scrawny and weak when they came back, but they managed.

On Mars, it has 1/3 the Earth's gravity, so it isn't like we'd be floating all over the place. In fact, the lessened gravity would probably be of considerable aid in constructing settlement camps since we'd be able to move the heavy equipment around with much greater ease.

The colonists would simply have to stay on a strict exercise regimen.

[Triple Word Score]

Saturn and beyond--brrrrr!

But it's warmer where Spirit is than it is in New York right now.

http://www.wokr13.tv/news/local/story.aspx?content_id=561A8B2D-697F-4A9B-BCC5-C1B3820B0B00

E=mc2, so we can stay warm ANYWHERE!

[ambrose]

Nothing wrong with teachers or the elderly, but it just mocks our entire space program. NASA can't become some airline to fly around politically approved passengers. It has to be understood this is VERY DANGEROUS and we aren't going to just sit around with our thumbs up our butts for years, not going anywhere, because there might be an accident and an astronaut may die.

[ambrose]

Saturn and beyond--brrrrr! But it's warmer where Spirit is than it is in New York right now.

I wonder what the temperature is on Uranus?

[Triple Word Score]

Yes. No more silly missions-for-show. We need to do it like we mean it, and go to stay.

http://www.heinleinsociety.org/index.html

[Triple Word Score]

The average surface temperature of Uranus is -205 º C.

I don't usually get my butt frosted like that...usually I get it flamed. ;-)

[ambrose]

The place we're going to really want to be at down the line is Titan. It is a treasure trove of natural resources.

Then there's Venus. The Soviets managed to land a few probes that sent back some images, but the probes didn't last long in the 800 degree surface temps. I think it may be quite some time where our technology will be advanced enough to do much exploration there.

[ambrose]

The average surface temperature of Uranus is -205 º C.

My understanding is that Uranus is mostly a bunch of gas, so I don't think we'll be landing any probes there any time soon.

[Triple Word Score]

I just finished rereading IMPERIAL EARTH. You're probably right that Titan could be the key to the solar system; Sir Clarke certainly agreed with you.

(Just found out that Ginny Heinlein died a year ago today. Her ashes were scattered to join her husband's at sea. I don't know if Arthur C. Clarke is still with us or not.)