Astronaut Sunita Williams working on the International Space Station on Jan. 31, 2007
Photograph courtesy of NASA

Astronaut Dr. Shannon Lucid was aboard the Mir space station for 188 days in 1996. When she returned to Earth, Lucid described herself as "wobbly." Once astronauts come back safely, physicians begin exhaustive tests to determine how weightlessness affects the heart, muscles, bones, blood, urine, saliva, balance, strength, aerobic capacity, and other details of physiology and anatomy.

One of the numerous effects of prolonged weightlessness is muscle atrophy. Developing a strategy to prevent muscle loss is a high priority for the National Aeronautic and Space Administration (NASA), and scientists have been measuring astronaut muscle mass before and after prolonged space flights for some time.

In this lesson, you'll use WebImage to investigate if there's a measurable muscle loss to explain Dr. Lucid's wobbliness. Magnetic resonance imaging (MRI) scans of astronauts were obtained before and after prolonged stays in space. In this lesson, all data about the astronaut's name, age, gender, and date and duration of space flight are deliberately omitted from the images to protect astronaut privacy. Although Dr. Lucid is an actual astronaut, we have no way of knowing whose calves we're examining.

Click Begin Lesson Here (above) to start the activity. WebImage may take a short while to load.