New data analysis indicates that NASA and its partners could have more cost-effective methods for dealing with the growing issue of orbital debris than previously thought.

A new report from NASA's Office of Technology, Policy, and Strategy provides agency leadership with new insight about how to measure the risks presented by orbital debris.

"Growing activity in Earth's orbit has brought us everything from faster terrestrial communications to a better understanding of our changing climate," said Charity Weeden, who leads NASA's OTPS. "These blossoming opportunities are resulting in a more crowded space environment. This study is part of NASA's work to rapidly improve our understanding of that environment as outlined in NASA's recently released Space Sustainability Strategy, by applying an economic lens to this critical issue.

Future missions to the moon and Mars must address many challenges, including preventing loss of bone and muscle tissue in astronauts. Research on the International Space Station is helping to address this challenge.

Without Earth's gravity, both bone and muscle atrophy, or become smaller and weaker. Early on, scientists realized that exercise is a critical part of maintaining healthy bones and muscles in space, just as it is on Earth. From simple elastic bands on early missions, exercise hardware has become increasingly advanced. Current equipment includes the Advanced Resistive Exercise Device (ARED) weight-lifting system, a second generation-treadmill called T2, and the Cycle Ergometer with Vibration Isolation and Stabilization System (CEVIS) cycling machine. Studies continue to refine this equipment as well as the intensity and duration of how astronauts use it, with crew members now averaging two hours of exercise per day.

Installed in 2008, ARED uses a piston and flywheel system to provide loading that essentially mimics weightlifting in weightlessness.