The TIPS satellite was deployed on 20 June 1996 at an altitude
of 1,022 kilometers (552 nautical miles). This experiment is
designed to increase knowledge about gravity-gradient tether
dynamics and
... the survivability of tethers in space. (Tethers can
be severed by space debris.) The National Reconnaissance Office
(NRO) is a sponsor of the TiPS program. While tethers have been
theoretically studied as a means for satellite stabilization,
propulsion, and electricity generation for some time, TiPS is
among the first successful tether deployments in space and is
the first experiment designed for long duration.
Additional information available at
http://projects.nrl.navy.mil/tips/
[Summary provided by U.S. Military]