July 28, 2004 Shift Report -------------------------- RADIATION SUMMARY ----------------- Significant solar activity: July 27 was one of the magnetic stormiest days at earth of solar cycle 23. The solar flare activity level was moderate. A total of 8 C and 2 M class events were recorded yesterday. (http://www.dxlc.com/solar/) CMEs reported for past two days: July 27-28: Several CMEs, at least partial halo, could be earth directed. These could cause radiation problems in the next couple of days. A C class event occurred today that had a duration of ~9 hours, one of the longest we've seen. Radiation Measurement Observed Observed/Limit --------------------- -------- -------------- ACE 2hr fluence 5.08e+07 1/7.1 (http://www.srl.caltech.edu/ACE/ASC/) GOES-10/P2 4-9 MeV protons `P4GM' 5.54e-02 1/1715 (ftp://ftp2.sec.noaa.gov/pub/lists/pchan/G10pchan_5m.txt) GOES-10/P5 40-80 MeV protons `P41GM' 8.82e-03 1/88 (ftp://ftp2.sec.noaa.gov/pub/lists/pchan/G10pchan_5m.txt) *ACIS* Orbital fluence (since perigee) 2.82E+09 **2.8 times over limit** (http://asc.harvard.edu/mta/alerts/current.dat) EPHIN rates (cts/cm^2-s-sr) at last comm. OBSERVED RADMON limit or observed/limit ---------------------------------------- -------- ----------------------------- E1300 (2.64-6.18 MeV electrons): 0.1 1/100 P4GM (5-8.3 MeV protons): 7.9 1/38 P41GM (41-53 MeV protons): 0.1 1/85 (http://cxc.harvard.edu/cgi-gen/mta/Snap/snap.cgi?action=Latest) ACIS focal plane temperature -119.9 C, at dddZhh:mm:ss 210Z12:54:45 July 29, 2004 Shift Report -------------------------- NOTES/ISSUES/PROBLEMS SCS 107 ran at 210:19:24:29, due to an E1300 trip. This is presumably due to the puffed up radiation belts. CAP 921, the contingency eclipse load, was run but was knowingly started too late due to late schedule of the comm start. With only about 30 minutes before eclipse, manual commanding was done to configure for eclipse -- this was possible because the attitude was only 17 degrees off solar normal and therefore suitable to hold through the eclipse. Eclipse commanding was successful, and the eclipse proceeded nominally. Because an earth occultation was upcoming, a load was built to go into gyro hold through the occultation and then return to normal point. Alternately we would go into normal sun hold, which would require some effort for recovery. The load was uplinked about 10 minutes before end of comm, and was successful.