The Space Technology and Research Vehicles STRV-1a and -1b were a pair of microsatellites designed to test new space technologies and make measurements of the space environment and its effect on spacecraft systems. The emphasis of the project was on low-cost, short timescale access to space and the rapid dissemination of experimental data. Although built and operated by the UK's Defense Research Agency, many experiments were collaborative, involving the Ballistic Missile Defense Organization, the European Space Agency and universities. After 2.5 years of operation the spacecraft were turned over to NASA and the University of Colorado for communications experiments.

Each spacecraft had a 50 cm cubic structure based on carbon/PEEK thermoplastic skinned aluminum honeycomb panels. Four GaAs solar panels provided 31-33W (BoL) to a 28V power distribution bus and 16 NiCd batteries. Platform requirements were approximately 19W, leaving 13W for payload operations. On-board data handling used a GEC Plessey MIL-STD-1750 processor employing radiation tolerant SOS technology. ESA CCSDS telemetry and telecommand standards were observed. Communications were through the S-band (2.2GHz); 125bps uplink and 1kbps downlink through a 1W omni-direction antenna.

Both STRVs were spin-stabilized at approximately 5rpm with attitude determination achieved via V-slit Sun and Earth sensors and analogue Sun sensors. Control was through magnetorquers and a cold gas thruster system.

Both spacecraft carried a variety of space technology and environment experiments. Even the spacecraft's' carbon/PEEK structures were considered experimental. Specific payloads on -1a were the Atomic Oxygen Experiment, Battery Recharge, Cold Ion Detector, Cosmic Ray and Dosimetry Monitor, Langmuir Probe, Radiation Dose Rate Sensor, Surface Charge Detector and the Xenon Plasma Charge Neutralizer. On-board the -1b were the Cryocooler/Vibration Suppression Experiment, Infrared Detectors, Neural Network Microprocessors, Radiation Environment Monitor, Single Event Upset and Radiation Monitor and the Solar Cell Technology Experiment.

Design Life: 1 year. Typical orbit: 36,000km x 280km, i=7 deg., elliptical GTO. Length: 0.45 m (1.47 ft). Maximum Diameter: 0.45 m (1.47 ft). Associated Launch Vehicle: Ariane 44LP, Ariane 5G.

• 1994 June 17 - STRV-1A - Launch Site: Kourou. Launch Vehicle: Ariane 44LP. Mass: 53 kg (116 lb). Perigee: 273 km (169 mi). Apogee: 31,321 km (19,461 mi). Inclination: 7.40 deg. Period: 547.70 min.

  50 cm cube; Space Technology and Research Vehicle; included solar cell tests.

• 1994 June 17 - STRV-1B - Launch Site: Kourou. Launch Vehicle: Ariane 44LP. Mass: 50 kg (110 lb). Perigee: 278 km (172 mi). Apogee: 31,817 km (19,770 mi). Inclination: 7.50 deg. Period: 557.00 min.

  50 cm cube; Space Technology and Research Vehicle; included solar cell tests.

• 2000 November 16 - STRV-1c - Launch Site: Kourou. Launch Vehicle: Ariane 5G. Mass: 4,758 kg (10,489 lb). Perigee: 680 km (420 mi). Apogee: 39,789 km (24,723 mi). Inclination: 6.30 deg.

  The two small STRV cubes were then ejected from the Ariane EPS stage ASAP-5 secondary payload structure at 0141 GMT. STRV-1c and 1d were small satellites built by the DERA (former Royal Aircraft Establishment), Farnborough, England. Mass was around 95 kg each. STRV-1c performed accelerated life testing of new components and materials in the high radiation environment of geosynchronous transfer orbit.

• 2000 November 16 - STRV-1d - Launch Site: Kourou. Launch Vehicle: Ariane 5G. Mass: 4,758 kg (10,489 lb). Perigee: 605 km (375 mi). Apogee: 39,282 km (24,408 mi). Inclination: 7.10 deg. Period: 708.30 min.

  STRV-1c and 1d were small satellites built by the DERA (former Royal Aircraft Establishment), Farnborough, England. Mass was around 95 kg each. STRV-1d carries an NRL Space Test Program experiment (S97-2), a camera, and technology and computer experiments.

• Space-Launcher.com, Orbital Report News Agency. Accessed at: http://www.orbireport.com/Log.html.

• McDowell, Jonathan, Jonathan's Space Home Page, Harvard University, 1997-present. Jonathan McDowell's complete on-line listing of all objects orbited and over 20,000 rocket launches Accessed at: http://www.planet4589.org/jsr.html.

• McDowell, Jonathan, Jonathan's Space Report (Internet Newsletter), Harvard University, Weekly, 1989 to Present. Essential internet newsletter recording worldwide weekly space events. Accessed at: http://www.planet4589.org/jsr.html.

• Krebs, Gunter, Gunter's Space Page, University of Frankfurt, 1996. Accessed at: http://www.skyrocket.de/space.

• NASA/GSFC Orbital Information Group Website, . Accessed at: http://oig1.gsfc.nasa.gov/.

• JPL Mission and Spacecraft Library, Jet Propulsion Laboratory, 1997. Accessed at: http://msl.jpl.nasa.gov/home.html.