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 an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation ( GPS), broadcasting, scient ...

built by

Lockheed Martin The Lockheed Martin Corporation is an American Arms industry, defense and aerospace manufacturer with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta on March 15, 1995. It is headquartered in North ...

. 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 bott ...

tether that was intended to deploy to a length of 6 km, and was intended to test a new space tether 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 1998-055C.

References

External links

STEX
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