The electron distribution in the Earth's radiation belts during July 1962 as measured by Telstar

Abstract

Results obtained from the electron detector on Telstar between July 10 and 31, 1962, are presented. The principal sensitivity of the detector is to electrons of energies between 0.25 and 1.0 Mev. Flux maps have been drawn for days 193–197, 203–207, and 208–212, 1962. Maximum omnidirectional electron fluxes of approximately 109/cm2 sec were encountered with energies in excess of 200 kev near the magnetic equator at L's of about 1.25 and 1.8Re. The intensity decreased exponentially with a time constant of about 4.5 days between L values of 2.2 and 3.0, and with a time constant of about 15 days at L = 2.0 and 3.5, creating a slot be tween the inner and outer electron belts that had become pronounced by the end of July. The energy spectrum encountered seems to contain a substantial number of electrons with energies of about a Mev or more and is not inconsistent with the fission β spectrum above 400 kev. At lower energies the spectrum is steeper. Within the sensitivity of the measurement no spectral changes with either position or time were observed. Because of Telstar's launch date it is not possible to conclude what fraction of the electrons measured were produced by the high‐altitude nuclear test of July 9. In spite of the high flux of electrons encountered, electrons are not the major source of radiation damage to the Telstar solar power plant.

Anthropogenic Space Weather

“…The plot is in the R-λ coordinate system, related to the McIlwain's B-L coordinate system (see Roberts, 1964). (From Brown et al, 1963) The launch of Telstar-1, on the day following the Starfish explosion, brought a very powerful observation platform into near-earth space, extremely well instrumented (for the time) to monitor the energetic particle population of the natural as well as of the artificial radiation belts (Brown et al, 1963). Helped by both its orbit (perigee = 952 km, apogee = 5632 km, inclination = 45 • ) and its instrumentation, it was able to map the Starfish radiation belt and follow its evolution.…”

Untitled

“…Furthermore, any Virtex device can be expected to operate for at least several decades before suffering any negative TID-related effects in a typical low Earth orbit (LEO). Although non-TID effects will likely disable the system before the expected TID-based operational lifetime expires, it may still be important to consider the operational lifetime due to solar flares and other sources of ionizing radiation, which can dramatically increase space radiation levels [Brown and Gabbe 1963]. Therefore, the lifetime metric is still useful for LEO-based missions, because during these events, an excessive operational lifetime could lead to months of useful operations as opposed to just days.…”

The Solar Cells and Their Mounting

“…18 The pulses are sorted into four channels, covering an energy-event range of 180 Kev to 990 Kev, The depletion layer width of the counter is such that electrons of energies between 200 Kev and 600 Kev are counted with relatively good efficiency as compared to those of higher energies. Thus, if the counter is operated in a radiation environment containing relatively high intensities of multi-Mev electrons, it is possible to get flux values only by making assumptions concerning their energy distribution.…”