Space Technology Experiments, or STEX, also known as NRO Launch 8 or NROL-8, was an experimental National Reconnaissance Office (NRO)

satellite A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioiso ...

built by Lockheed Martin. It was launched on 3 October 1998. One of the experiments was ATEx (Advanced Tether Experiment), which was deployed on 22 January 1999, and subsequently jettisoned.

ATEx

The Advanced Tether Experiment (ATEx), was a follow on to the TiPS experiment, designed and built by the Naval Center for Space Technology, flown as one of the experiments on STEX. ATEx had two end masses connected by a

polyethylene Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging (plastic bags, plastic films, geomembranes and containers including ...

tether that was intended to deploy to a length of 6 km, and was intended to test a new

space tether Space tethers are long cables which can be used for propulsion, momentum exchange, stabilization and attitude control, or maintaining the relative positions of the components of a large dispersed satellite/spacecraft sensor system. Depending on t ...

deployment scheme, new tether material, active control, and survivability. ATEx was deployed on 16 January 1999 and ended 18 minutes later after deploying only 22 m of tether. The jettison was triggered by an automatic protection system designed to save STEX if the tether began to stray from its expected departure angle, which was ultimately caused by excessive slack tether. As a result of the deployment failure, none of the desired ATEx goals were achieved. ATEx is now tracked as a separate object as USA 141 or

COSPAR ID The International Designator, also known as COSPAR ID, is an international identifier assigned to artificial objects in space. It consists of the launch year, a three-digit incrementing launch number of that year and up to a three-letter code repr ...

1998-055C.

References

External links

STEX
at Gunter's Space Page Spacecraft launched in 1998 Satellites of the United States {{US-spacecraft-stub