Scientists hope fruit flies will help them better understand health risks in space during NASA's next shuttle mission. Images: Flies in outer space
To help scientists study what happens to astronauts' health in space, 100 fruit flies will buzz along for the ride.
During a routine journey through space, astronauts spend their days floating in microgravity, the virtual absence of gravitational pull. That weightlessness affects many systems in the human body. One established effect is the temporary impairment of the immune system. Wounds, for example, take longer to heal.
At the same time, certain bacteria can mutate and become more powerful--a bad combination. Even if risks are minor during a 12-day mission like the upcoming shuttle flight, they deserve to be explored, said Cecilia Wigley, manager of a new immunity research project at NASA.
"We are looking down the road to the president's vision of eventually going to Mars," she said. "As we go into longer-duration flight, as well as longer distances, the body's ability to fight off infection becomes quite critical to the health of astronauts."
Hoping to figure out what the less obvious health risks of traveling in space are, the NASA researchers are preparing fruit flies for extraterrestrial travel. Since they have an immune response system similar to that of humans and don't demand much space or nutrition, they are well-fit for a space experiment, NASA says.
The tiny passengers will be traveling in a middeck locker, where 100 adult males and females will float around in a vented container, eating and mating. During the 12-day flight, they are expected to produce a second generation, which will have time to go from embryos to larvae and adult flies.
The insects are low-maintenance pets; astronauts will only have to feed them once, by changing an escape-proof food cassette containing a mix of sugar and yeast.
This is not the first time fruit flies will ride in a spacecraft; they were actually the first living creatures ever sent into space--long before Laika, a Russian dog, was sent into orbit on Sputnik 2.
In July 1947, the United States launched a V2 rocket carrying just fruit flies and a box of corn seeds to investigate the effects of high-altitude radiation exposure.
On this summer's mission, not all of the flies being prepared get to go. Half of the insects will stay on the ground as a genetically identical control group, waiting for their counterparts to land at the Kennedy Space Center laboratory in Florida. "They will be loaded in the same type of containers and put into an environmental chamber. It uses data that is downlinked from the shuttle to provide the same conditions," Wigley said.
Temperature, humidity and food will be kept the same, and when the space flies land, all the insects will be exposed to a fungus that easily infects them. Under normal conditions, an attack will spur the immune system into action, making the body produce extra blood cells and antimicrobial proteins that take down intruders.
To decide whether the time in weightlessness has weakened the flies or mutated the fungus, their levels of blood cells and proteins will be measured and compared in both control groups.
Depending on results from this trial, the immune research project will continue, and fruit flies might become a common sight in space.