ESRO 2B

Spacecraft

ESRO-2B was an 89 kg cylindrical spacecraft with a length of 85 cm and a diameter of 76 cm. On 10 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. Other experiments could still be operated through ground radio links.

ESRO-2B was launched on a Scout B rocket into a highly elliptical near-polar orbit on 17 May 1968. Its predecessor satellite, ESRO-2A (sometimes Iris 1) failed to reach orbit on 29 May 1967, launching on a Scout B rocket from Vandenberg AFB SLC-5. The cause of failure was malfunction of the third stage of the rocket, preventing the satellite from reaching orbit. ESRO-2A was similar to ESRO-2B except it weighed a little less (74 kg).

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

Instruments

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. The instruments were:

• Monitor of Energetic Particle Flux
• Solar and Van Allen Belt Protons
• Solar and Galactic Alpha Particles and Protons
• Primary Cosmic Ray Electrons
• Hard Solar X-rays
• Soft Solar X-rays
• Flux and Energy Spectra of Solar and Galactic Cosmic Ray Particles

References

References

1. "NASA – NSSDCA – Spacecraft – Details".
2. "ESRO 2B". NASA.
3. "NASA – NSSDCA – Spacecraft – Trajectory Details".
4. "ESRO 2B: May – December 1968". University of Indiana.
5. "NASA – NSSDCA – Spacecraft – Details".
6. "ESRO 2A, 2B (Iris 1, 2)". Gunters Space Page.