Images: Flies--not pigs--in space

This is what NASA's latest space travelers look like. About a hundred common fruit flies, or Drosophila melanogaster, will be on board when the shuttle Discovery takes off, an event planned for July 1. During the 12-day flight, the flies are expected to produce a new generation of flies, which will help scientists explore health issues in space.

The miniature "space shuttle" for flies has been specially designed for the immune response experiment to be carried out on Discovery. In the vented container, flies will float around in weightlessness while mating and eating.

About 25 males and female flies will travel through space in each of five cassettes like this one. After landing, they will be exposed to an infectious fungus and monitored for defects in their immune systems.