NASA's Science Mission Aborted, Technology Review
"Although the International Space Station remains a budgetary priority, some scientists feel that its usefulness for carrying out scientific research has already been diminished, by, for example, the cancellation of a large centrifuge seen as essential for biological research. That cancellation, says Keith Cowing of the watchdog website NASA Watch, will "set back the ability" to develop ways to prevent the loss of muscle and bone by astronauts in prolonged weightlessness. And yet, he says, President Bush's exploration initiative is supposed to be leading toward trips to "Mars and beyond," where such measures will be essential."
U of M study examines kidney stone prevention in astronauts
"At least 14 American crew members have developed kidney stones in the last 5 years, and as missions become longer, the number is likely to grow. While astronauts have exercised in space to attempt to combat bone loss, the lack of gravity makes it difficult to achieve enough resistance to maintain their pre-flight fitness levels."