Preventing Sick Spaceships

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Preventing " Sick " Spaceships

YubaNet - Nevada City,CA

By: Trudy E. Bell, Science@NASA

http://www.yubanet.com/artman/publish/article_56792.shtml

Mir, orbiting high above New Zealand in 1996.

Picture this: You're one of several astronauts homeward bound after

a three-year mission to Mars. Halfway back from the Red Planet, your

spacecraft starts suffering intermittent electrical outages. So you

remove a little-used service panel to check some wiring.

To your unbelieving eyes, floating in midair in the microgravity

near the wiring is a shivering, shimmering globule of dirty water

larger than a grapefruit. And on the wiring connectors are

unmistakable flecks of mold.

That actually happened on the Russian space station Mir. When Mir

was launched in 1986, " it was as clean as the International Space

Station when it was launched, " recounted C. Mark Ott, health

scientist at Space Center in Houston, Texas. And the

cosmonauts aboard Mir (just like the astronauts from the U.S. and

other nations aboard ISS) followed a regular schedule of cleaning

all the space station's surfaces to prevent the growth of bacteria

and molds that could jeopardize human health.

Yet, wherever humans venture, microorganisms follow-and make

themselves right to home, thank you, if conditions are right.

In the late 1990s, NASA joined the Russian space program in its

evaluation of the microbial activity aboard Mir. For planning long-

duration missions, they wanted to learn about the kinds of organisms

that can grow in spacecraft occupied for long periods of time and

where air and water are recycled. They were especially interested

because several times during its 15 years in low Earth orbit, Mir

had had the misfortune to suffer several power outages, so the

temperature and humidity rose well above normal levels and air

circulation was inadequate until the electricity was restored.

In 1998, U.S. astronauts participating in the NASA 6 and NASA 7

visits to Mir collected environmental samples from air and surfaces

in Mir's control center, dining area, sleeping quarters, hygiene

facilities, exercise equipment, and scientific equipment. Imagine

their surprise when they opened a rarely-accessed service panel in

Mir's Kvant-2 Module and discovered a large free-floating mass of

water. " According to the astronauts' eyewitness reports, the globule

was nearly the size of a basketball, " Ott said.

This dust mite was found floating in a globule of water onboard Mir.

Other microorganisms collected include protozoa and amoeba.

Moreover, the mass of water was only one of several hiding behind

different panels. Scientists later concluded that the water had

condensed from humidity that accumulated over time as water droplets

coalesced in microgravity. The pattern of air currents in Mir

carried air moisture preferentially behind the panel, where it could

not readily escape or evaporate.

Nor was the water clean: two samples were brownish and a third was

cloudy white. Behind the panels the temperature was toasty warm-82ºF

(28ºC)-just right for growing all kinds of microbeasties. Indeed,

samples extracted from the globules by syringes and returned to

Earth for analysis contained several dozen species of bacteria and

fungi, plus some protozoa, dust mites, and possibly spirochetes.

But wait, there's more. Aboard Mir, colonies of organisms were also

found growing on " the rubber gaskets around windows, on the

components of space suits, cable insulations and tubing, on the

insulation of copper wires, and on communications devices, " said

Steele, senior staff scientist at the Carnegie Institution of

Washington working with other investigators at Marshall Space Flight

Center.

Fungi on the ISS, growing on a panel where exercise clothes were

hung to dry. " This is a good example of how biological contamination

isn't an old problem or just specific to Mir, " points out Mark Ott.

Aside from being unattractive or an issue for human health,

microorganisms can attack the structure of a spacecraft

itself. " Microorganisms can degrade carbon steel and even stainless

steel, " Steele continued. " In corners where two different materials

meet, they can set up a galvanic [electrical] circuit and cause

corrosion. They can produce acids that pit metal, etch glass, and

make rubber brittle. They can also foul air and water filters. "

In short, germs can be as bad for a spacecraft's health as for crew

health.

That's one reason that Marshall is developing the Lab-On-a-Chip

Application Development–Portable Test System, or LOCAD-PTS for

short. LOCAD-PTS is a handheld device that can diagnose the presence

of bacteria or fungi on the surfaces of a spacecraft within minutes,

far more rapidly than standard methods of culturing, which may take

several days and may require return to Earth for further analysis.

" LOCAD-PTS is an excellent example of the kind of hardware

astronauts will need to be autonomous in a lunar habitat or a long-

duration mission to Mars, " Steele explained. " Crews must be able to

make assessments on their own. They may not be able to get samples

back to Earth. " Although no electrical or mechanical failure on Mir

was specifically traced to biodegradation, " it's not a chance you

would want to take en route to Mars. "

An early version of LOCAD-PTS, which can test for one major category

of bacteria (called Gram-negative bacteria, accounting for about

half of all bacterial species) is being tested aboard ISS right now.

New cartridges for the unit, due to be sent up to ISS in early 2008,

will be able to test for almost all major categories of bacteria

(Gram positive as well as Gram negative) and also for fungi.

Meantime, this fall (2007), an even more advanced version-which can

sense 130 specific microorganisms, not just broad categories-Steele

will test in the Arctic.

The ultimate plan is to develop a handheld device that can identify

thousands of individual microorganisms. " The arrays of tests on

LOCAD-PTS can be tailored to look at specific questions, " Steele

said. " For example, one array might look for genes and chemical

compounds associated with biodegradation of a spacecraft's

structure, whereas another array might look for human pathogens, or

try to detect life on Mars. "

By getting the results of the tests in minutes, astronauts would

then know which cleaning compound would work best to prevent a

spacecraft or habitat from " falling ill. "