The Earth Probe spacecraft went into safehold last Friday (August 2, 2002 at 0944 UTC) when a single event upset (SEU - basically a high energy particle hitting a memory location) hit the attitude channel. This has happened before, in 1997 and again in 1998. We followed our usual procedure, taking several days to be sure we understood exactly what happened. Then yesterday (August 7, 2002), we put the Earth Probe spacecraft back into normal mode and partially turned the TOMS instrument back on. To be sure that we don't get any more contamination after the cold soak TOMS has been through, we plan to wait until Monday (August 12, 2002) to unstow the mirror and resume taking data. Just being very conservative.
For additional details, check out the TOMS News Page.