Encyclopedia Astronautica
REX


American earth ionosphere satellite. 2 launches, 1991.06.29 (REX) and 1996.03.09 (REX-II). The REX satellites were designed to study scintillation effects of the Earth's atmosphere on RF transmissions.

Rex 2 was also the first spacecraft to successfully employ GPS navigation for full closed loop attitude control.

The basic design features of both REX spacecraft were similar, though there were some obvious differences, i. e. no GPS equipment on the first REX. Specifications presented here are for Rex 2. The spacecraft was three axis stabilized, nadir pointing to within 5 degrees. Passive attitude control was provided by a 21 foot gravity gradient boom with two 20 inch long nickel/iron magnetic hysteresis rods mounted at the tip for damping purposes (4 lbs. total). Active control was achieved through a pitch bias momentum system, including one wheel and three torque coils. Attitude determination was provided by GPS equipment, coarse sun sensors, and a magnetometer. The primary communications experiment was built by the US Air Force Rome Laboratories. It advanced research on electron density irregularities that caused disruptive scintillation effects on radio signals transmitted through the Earth's ionosphere. Rex II's GPS receivers, supplied by Trimble Navigation, were able to resolve spacecraft position to 100m, velocity to 0.2 m/sec, and attitude to within 0.3 deg.

AKA: Radiation Experiment.
Gross mass: 85 kg (187 lb).
Height: 0.56 m (1.83 ft).
First Launch: 1991.06.29.
Last Launch: 1996.03.09.
Number: 2 .

More... - Chronology...


Associated Countries
See also
  • Pegasus Privately-funded, air-launched winged light satellite launcher. More...
  • Scout Solid-fuel, light payload, lower-cost launch vehicle developed by the Air Force and NASA in the late 1950's and used in a variety of configurations over thirty years. Launched from Cape Canaveral, Vandenberg, Wallops Island, and from Italy's equatorial San Marco platform off Kenya. Italy studied but did not develop subsequent upgraded versions. More...

Associated Launch Vehicles
  • Scout American all-solid orbital launch vehicle. Solid-fuel, light payload, lower-cost launch vehicle developed by the Air Force and NASA in the late 1950's and used in a variety of configurations over thirty years. Launched from Cape Canaveral, Vandenberg, Wallops Island, and from Italy's equatorial San Marco platform off Kenya. Italy studied but did not develop subsequent upgraded versions. More...
  • Scout G American all-solid orbital launch vehicle. Four stage vehicle consisting of 1 x Algol 3A + 1 x Castor 2 + 1 x Antares 3 + 1 x Star 20 More...
  • Pegasus American air-launched orbital launch vehicle. Privately-funded, air-launched winged light satellite launcher. More...
  • Pegasus XL American air-launched orbital launch vehicle. Uprated version of Pegasus air-launched winged light satellite launcher. 4 stage vehicle consisting of 1 x L-1011 + 1 x Pegasus XL stage 1 + 1 x Orion 50XL + 1 x Orion 38. More...

Associated Manufacturers and Agencies
  • USAF STP American agency overseeing development of spacecraft. USAF STP, USA. More...
  • CTA American manufacturer of spacecraft. CTA, Inc. , Virginia, Virginia, Virginia, USA More...

Bibliography
  • McDowell, Jonathan, Jonathan's Space Home Page (launch records), Harvard University, 1997-present. Web Address when accessed: here.
  • McDowell, Jonathan, Jonathan's Space Report (Internet Newsletter), Harvard University, Weekly, 1989 to Present. Web Address when accessed: here.
  • JPL Mission and Spacecraft Library, Jet Propulsion Laboratory, 1997. 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...
  • Point Arguello WADZ Air-launched rocket drop zone known to have been used for 28 launches from 1990 to 2007, reaching up to 4539 kilometers altitude. More...
  • Vandenberg SLC5 Scout launch complex. Dedicated Scout launch pad, used during the life of that vehicle from 1962 to 1994. More...

REX Chronology


1991 June 29 - . 14:00 GMT - . Launch Site: Vandenberg. Launch Complex: Vandenberg SLC5. LV Family: Scout. Launch Vehicle: Scout G. LV Configuration: Scout G-1 S216C.
  • REX - . Payload: REX 1. Mass: 85 kg (187 lb). Nation: USA. Agency: USAF Rome. Class: Earth. Type: Ionosphere satellite. Spacecraft: REX. USAF Sat Cat: 21527 . COSPAR: 1991-045A. Apogee: 869 km (539 mi). Perigee: 767 km (476 mi). Inclination: 89.5000 deg. Period: 101.30 min. Summary: Radiation Experiment; tested communications components in high radiation environment. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B)..

1996 March 9 - . 01:53 GMT - . Launch Site: Point Arguello WADZ. Launch Pad: 36.0 N x 123.0 W. Launch Platform: L-1011. LV Family: Pegasus. Launch Vehicle: Pegasus XL. LV Configuration: Pegasus XL F10.
  • REX-II - . Nation: USA. Agency: USAF STP. Class: Earth. Type: Ionosphere satellite. Spacecraft: REX. USAF Sat Cat: 23814 . COSPAR: 1996-014A. Apogee: 835 km (518 mi). Perigee: 799 km (496 mi). Inclination: 90.0000 deg. Period: 101.20 min. Summary: LEO .

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