Citation
Abstract
Signal-strength fluctuations on a spacecraft-to-Earth link due to solar charged particles can degrade telemetry performance. The degree of amplitude scintillation induced on an emitted spacecraft signal by the intervening charged particles of the solar corona during a spacecraft-to-Earth superior conjunction depends on the minimum distance from the Sun of the signal ray path (solar elongation), the current phase of the solar cycle (solar maximum versus solar minimum), and the sub-solar latitude of the signal path. For spacecraft telemetry, frame errors have been observed to significantly increase due to scintillation, when the solar elongation becomes small enough, or when the solar coronal environment of the signal path is plagued with solar activity such as coronal mass ejections or streamers. This degradation in telemetry data return occurs at solar elongation angles of 2 deg and below at 8.4 GHz (X-band) and is expected to start occurring at about 1 deg at 32 GHz (Ka-band). This article presents both theoretical and statistical models, which have been derived based on spacecraft solar conjunction measurements to characterize the degree of solar scintillation as a function of solar elongation angle at both X-band and Ka-band. Such models may be useful to flight projects and design engineers in the planning of solar conjunction operational scenarios.
Details
- Volume
- 42-153
- Published
- May 15, 2003
- Pages
- 1–14
- File Size
- 144.9 KB