Microscopic proteins are loaded into tiny chambers on plastic cards, and then flash-frozen to stabilize them for the trip to space.
The frozen proteins were shipped to space on the SpaceX Dragon spacecraft March 1.
At the International Space Station the proteins will thaw and begin forming crystals.
Astronauts will use a microscope attached to a computer to take images of the growing crystals for review back on earth.
In May the crystals will be shipped back and X-rayed to produce 3-D images of the proteins, which will then be compared to a set of crystals grown on earth.