Solar Bulletin, December 2003

• Sudden Ionospheric Disturbance Report

Click image to enlarge. Fig. 1. 10 cm Solar Flux and American Relative Sunspot Numbers (Ra) for December 2003 (10cm Source: http://www.drao.nrc.ca/icarus)

Click image to enlarge. Fig.2 Maximum, Mean, and Minimum Ra Values for Each Month from January 2001 to Present.

Table IV. Sunspot and SID Observers Who Contributed Reports During 2003

Michael Hill, SID Analyst 114 Prospect St Marlborough, MA 01752 USA noatak@aol.com

Observer Code Station(s) monitored A Clerkin A29 NAA J Winkler A50 NAA NPM NXX D Toldo A52 NAA NSS NWC J Ellerbe A63 ICV P King A80 HWU W Moos A84 FTA ICV M Hill A87 NAA G DiFillipo A93 DHO HWU T Poulos A95 NAA J Wallace A97 NAA M King A99 HWU P Campbell A100 NLK F Steyn A102 NWC P Mortfield A108 NLK

The events listed above meet at least one of the following criteria Event reported by two or more observers within +/- 5 minutes Event matched to GOES-8 XRA event to within +/- 15 minutes and event time < 1000 UT Reported by observer with a high quality rating > 8 (scale 1-10)

Solar Events

I read about an interesting affect of the large solar flares back in October just recently. The spacecraft flying to Mars carrying the first Rover, Spirit, performs attitude control operations using a star tracker which compares the view of the stars with maps stored in memory in order to determine where it is pointed. The spacecraft also contains a backup attitude determination system that relies on a Sun Sensor. Sun sensors use the sun as a reference for attitude determination. Apparantly the burst of high energy particles coming from the X17.1 flare on Oct 28th caused the star tracker to see points of light that were not really stars thereby comprimising its operation for a while. The backup Sun Sensors had to be used to take over until the Star Tracker could be brought back to operational status. The large flares do affect us in many ways. This is just one example and is one of the reason spacecraft electronics have to be radiation hardened and why systems have to include backups and redundancy. Any mission in space has to take the solar cycle into consideration. This includes orbiting satellites, scientific satellites or manned spacecraft.