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Laboratory for Atmospheric and Space Physics

Space weather May 98

September 24, 2012

During May there were several spacecraft anomalies:

  • Equator-S stopped transmitting data on May 1
  • Polar suffered an anomaly May 6 that stopped its processor
  • PanAmSat’s Galaxy-4 failed May 19, disrupting paging and other communications services in the U.S.

The Polar spacecraft anomaly coincided with the rise phase of an solar energetic particle event on May 6, and was likely caused by a Single Event Upset (SEU) from energetic heavy ions from the solar particles While the causes of the Equator-S and Galaxy-4 failures are yet undetermined, it may be significant that they coincided with a intense build-up of penetrating electron fluxes in the magnetosphere, as shown by the accompanying SAMPEX spectrogram

The color spectrogram shows deeply penetrating (“killer”) electron intensities measured by SAMPEX for April 1- May 21 Arrows mark times of Equator-S failure (day 121),Polar anomaly (day 126), and Galaxy-4 failure (day 139).

Prior satellite anomalies (e.g. the loss of control of the Canadian Anik-1 and -2 communications satellites on Jan. 20, 1994) have occurred after extended periods of increased relativistic electron intensities

Contributed by Dan Baker, LASP, University of Colorado at Boulder

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