An example of how the Sun affects our satellite fleet happened on April 5, 2010. Unusually violent solar activity caused the Galaxy 15 satellite to stop responding to ground commands. A backup satellite is being moved into position and it is hoped that Galaxy 15 will be recovered.
Wednesday, April 28, 2010
SDO Day 78: Just the CCD Facts, Ma'am
SDO has 10 CCDs, 8 inside the science instruments and 2 in the star trackers. The science CCDs operate at very low temperatures. The EVE CCDs are 2Kx2K pixels and operate at -100 C. The HMI and AIA CCDs are 4Kx4K and operate at about -70 C. HMI has 2 high-grade visible light CCDs while AIA and EVE treated their CCDs to make them more suitable for detecting extreme ultraviolet light. To cool a CCD we hook it to a radiator panel and keep the Sun off the panel. Thermal radiation leaving the panel is enough to send into space the small amount of heat generated by operating the CCD.