Small samples in the centrifuge will spin at varying rates to create synthetic gravity, like the gravity of Mars or the gravity of the moon, and measure how the specimens respond within the centrifuge.
In the 19th Century people were looking for the Northwest Passage. Ships were lost and brave people were killed, but that doesn't mean we never went back to that part of the world again, and I consider it the same in space exploration.
I never made a career decision based solely on my desire to be an astronaut. I attended the Naval Academy because I wanted to be a Navy pilot. I majored in math because math had always come pretty easily to me and I liked it.
Since the Columbia accident, the Russian space agency, or the Russian space program, has been literally carrying the load bringing us all the supplies we need on the Progress vehicle, smaller amounts on the Soyuz vehicles.