After the nine-day flight, the 77-year-old astronaut and U.S. senator from Ohio will be examined by Dr. Eran Schenker, a space medicine expert from Hadassah-University Hospital in Jerusalem, and Schenker's team.

The absence of gravity speeds up the loss of calcium, "much beyond what occurs on Earth," Schenker said Sunday. "We will compare the process of calcium loss in the mouse bone cells with what happens in Glenn's body. This could lead to better understanding and treatment of osteoporosis."

The $3 million test, being conducted in cooperation with researchers in Canada and the United States, is the fourth Israeli-designed experiment to go up in space.