Long Duration Exposure Facility

Long Duration Exposure Facility (LDEF) was left in low Earth orbit (LEO) for 5.7 years before being retrieved by space shuttle Columbia in January 1990.

More than 20,000 impacts have been documented on LDEF, approximately 1,000 of which have been chemically analyzed in an attempt to determine the origin of the projectile. These measurements have provided NASA scientists important information not only on the micrometeoroid and orbital debris populations, but their orbital distributions as well.