Encyclopedia Astronautica

American tether technology satellite. One launch, 1998.10.03. STEX's (Space Technology EXperiments) main equipment was provided by the Naval Research Laboratory.

These included:

  • Hall Effect electric thrusters derived from Russian technology
  • Experimental solar arrays and batteries
  • ATEX advanced tether experiment, a follow-on to the earlier TIPS satellite. This comprised two end masses connected by a 6 kilometer polyethylene tether. The upper end mass was to be deployed first, while the lower end mass remained attached to STEX. After a series of dynamics experiments in this configuration, the lower end mass was to be separated from STEX and the ATEX became a free-flying pair subsatellite. In the event, the ATEX was jettisoned from STEX after the tether had only deployed 21 m.

First Launch: 1998.10.03.
Number: 1 .

More... - Chronology...

Associated Countries
See also
  • Taurus Pad-launched launch vehicle using Pegasus upper stages and Castor-120 first stage. More...

Associated Launch Vehicles
  • Taurus American all-solid orbital launch vehicle. Pad-launched launch vehicle using Pegasus upper stages and Castor-120 first stage. First launch used slightly larger Peacekeeper ICBM first stage instead of Castor-120. Under a 2002 contract from Boeing, Orbital developed a three-stage version of Taurus to serve as the interceptor boost vehicles for the US government's missile intercept system. The firm portion of the company's contract, awarded in early 2002, was valued at $450 million and extended through 2007. More...
  • ARPA Taurus American all-solid orbital launch vehicle. Four stage version consisting of 1 x TU-904 + 1 x Orion 50 + 1 x Orion 50 + 1 x Orion 38 More...

Associated Manufacturers and Agencies
  • NRO American agency overseeing development of spacecraft. National Reconnaissance Office, USA. More...
  • Martin American manufacturer of rockets, spacecraft, and rocket engines. Martin Marietta Astronautics Group (1956), Denver, CO, USA. More...

  • McDowell, Jonathan, Jonathan's Space Home Page (launch records), Harvard University, 1997-present. Web Address when accessed: here.
  • McDowell, Jonathan, Launch Log, October 1998. Web Address when accessed: here.

Associated Launch Sites
  • Vandenberg Vandenberg Air Force Base is located on the Central Coast of California about 240 km northwest of Los Angeles. It is used for launches of unmanned government and commercial satellites into polar orbit and intercontinental ballistic missile test launches toward the Kwajalein Atoll. More...

STEX Chronology

1998 October 3 - . 10:04 GMT - . Launch Site: Vandenberg. Launch Complex: Vandenberg 576E. LV Family: Pegasus. Launch Vehicle: ARPA Taurus. LV Configuration: ARPA Taurus T3 1110.
  • STEX - . Payload: STEX. Nation: USA. Agency: NRO. Manufacturer: NRL. Class: Technology. Type: Ion engine technology satellite. Spacecraft: STEX. USAF Sat Cat: 25489 . COSPAR: 1998-055A. Apogee: 759 km (472 mi). Perigee: 744 km (462 mi). Inclination: 84.9859 deg. Period: 99.77 min. Tested TAL-D55 plasma engine and was to be part of the NRO's ATex tether experiment. The ATeX lower end mass was meant to remain attached to the STEX parent spacecraft, but with only 21 m of tether deployed, it appeared the tether was so far off vertical that automatic safety systems jettisoned the base to protect the remainder of the STEX satellite. Thus, the upper and lower ATeX end masses were in orbit as one object connected by a 21 m tether, and designated USA 141 (1998-055C). The main STEX satellite was in orbit as a separate object, 1998-055A.

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