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Mission description

On 17 Jun 1994 the Space Technology Research Vehicle (STRV-1b) with a REM aboard was launched into space with an Ariane rocket from ESA. The orbit of the STRV-satellite is highly eliptical with apogee and perigee altitude of 300 km and 36000 km, respectively and a period of +/- 10 hours. Its inclination with respect to the Earth equator is 7° (GTO). The GTO passes repeatedly through the Earth radiation belts and is an excellent orbit for studying the radiation environment through a range of altitudes.

Detector description

The REM detectors consists of two thin (ca. 300 mm thick), totally depleted silicon diodes, measuring the differential linear energy transfer (LET) of charged particles. The detector electronics measures the energy deposit and increments one of 16 counters. Data is accumulated over a period of typically 100 seconds and then stored as a 16-bin histogram. The two detectors differ in size (150 mm2 and 50 mm2) and shielding. Both detectors are covered with a spherical dome of 3 mm Al and the larger detector with additional 0.75 mm Ta. Whereas the first detector sees protons as well as electrons (called e-detector) the extra tantalum of the second detector reduces the penetration for electrons in the relevant energy range (2 - 10 MeV) by approximately a factor of 200 and makes this detector better at monitoring protons (energy range 35 - 300 MeV) (called p-detector). Due to the variation of the energy loss of protons in silicon in this energy range the incident energy of the protons is measured, whereas the incident energy of the detected electrons is only poorly determined.

NameSTRV 1b (Space Technology Research Vehicle)
Orbit typeGTO
Perigee: 300 km, Apogee: 36000 km, Inclination: 7°
Launch date/time17 Jun 1994
InstrumentREM Radiation Environment Monitor
Data coverage23/06/1994 - 31/12/1997
Data resolutionTypical accumulation time: 100 s
PIA. Zehnder (Paul Scherrer Institute)
SourceCD-ROM from PSI
L-coverage0 - 8 RE
Data set
AltitudeData set
LatitudeData set
LongitudeData set
Calculated BCalculated at BISA with UNILIB
  • Internal magnetic field: DGRF/IGRF
  • External magnetic field: Olson & Pfitzer quiet
McIlwain's L parameterCalculated at BISA with UNILIB
  • Internal magnetic field: DGRF/IGRF
  • External magnetic field: Olson & Pfitzer quiet
Proton fluxesp+: 24.0 - 45.0 MeV
p+: 45.0 - 90.0 MeV
p+: 90.0 - 170.0 MeV
p+: 170.0 - 320.0 MeV
p+: 320.0 - 600.0 MeV
Electron fluxese-: 1.0 - 2.2 MeV
e-: 2.2 - 4.6 MeV
Restricted dose rate behind 0.81 g cm-2 (Al)Calculated at BISA
Restricted dose rate behind 2.06 g cm-2 (Al + Ta)Calculated at BISA


  1. A number of records from the original data set have been omitted because of overlapping time stamps.
  2. The original data set includes a third electron channel, but this was not included here as most of the values are 0.
  3. Fluxes which are lower than the estimated error are not included.
  4. In the original data set, fluxes were sometimes calculated for other energy bins than the ones in the table above. These have not been included.
  5. Fluxes in the period from 21 SEP 1996 until 30 Nov 1997 are not provided.
  6. The restricted dose calculation is an approximation only. The first two channels of each detector were not taken into account, as these are contaminated with noise.


Bühler, P., The Radiation Environment Monitor, Scientific Data Extraction, Part II: REM-CDF database, 1996.

Bühler, P., S. Ljungfelt, A. Mchedlisshvili, N. Schlumpf, A. Zehnder, L. Adams, E. Daly, and R. Nickson, Radiation environment monitor, Nucl. Instr. and Meth. in Phys. Res. A 368, pp. 825-831, 1996.

Desorgher L., P. Bühler, A. Zehnder, E. Daly, L. Adams, Outer radiation belt variations during 1995, PSI-PR-97-02, 1997.

Last update: Mon, 12 Mar 2018