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Mission type  Astrophysics
Rocket  Scout B
Decay date  8 May 1971
Launch date  17 May 1968
Inclination  97.2°
Launch mass  89 kg
Operator  ESRO
Launch site  Vandenberg SLC-5
Reference system  Geocentric
Inclination  97.2°
Period  1.6 hours
Launch mass  89 kg
ESRO 2B httpsuploadwikimediaorgwikipediacommonsthu
Similar  Jupiter Ganymede Orbiter, Olympus‑1, MICROSCOPE, European Retrievable Carrier, Advanced Telescope for High E

ESRO-2B or Iris (International Radiation Investigation Satellite) was a European astrophysical spin-stabilised research satellite which was launched in 1968. Operated by the European Space Research Organisation, ESRO 2B made astronomical surveys primarily in x-ray and solar particles detectors.



ESRO-2B was an 89 kg (196 lb) cylindrical spacecraft with a length of 85 cm and a diameter of 76 cm. In December 1968 (approx 195 days since mission start) the on-board tape recorder suffered a mechanical failure. This effectively ended the two X-ray experiments as they did not provide any significant data return from then on.

ESRO-2B was launched on a Scout B rocket into a highly elliptical near-polar orbit on 16 May 1968 after the ESRO-2A failed to reach orbit.

Spin-stabilised, ESRO-2B had a spin rate of approximately 40 rpm and re-entered the Earths atmosphere on 8 May 1971 after completing 16,282 orbits.


Seven instruments were carried aboard EROS 2B designed to detect high energy cosmic rays, determine the total flux of solar X-rays and to measure Van Allen belt protons and cosmic ray protons. While designed for solar observations ESRO-2B is credited with the detection of X-rays from non-solar sources.


ESRO 2B Wikipedia

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