Date: Thu, 23 Jan 92 02:20:59 -0800
Subject: Short Status Report - SEU on 23-Jan-92

Hello Everyone,

This is a short status report for Fri, 23-Jan-92.

1. Today the SXT experienced another SEU between the 3rd and 4th KSC
contact.  During the 4th pass we discovered that a filter hard error had
caused the DP-J to turn off the power to the peripherals.  This causes an
"open-shutter" indication, and so Yohkoh was pointed to the east by 21
arc-min as a precaution.  During the 5th pass a checksum was performed
(with Sam Freeland in attendance) which verified that a code corruption
had occurred, indicating that the primary cause was probably an SEU.
Next, the recovering sequence was initiated, but because of a typing
error, it was not possible to complete the sequence before the end of
the pass.  The SXT is currently in a same configuration (shutter is
closed), but is not taking data.  We will attempt to complete the
recovery sequence tomorrow (Sat) at the first pass.


2. Unfortunately, Tsuneta san was ill today, so we were not able to
perform the ram patch to implement the checksum function for each SXT
exposure.  We are hoping that S.T.'s health will improve so that we can do
this tomorrow after the recovery sequence has been completed.  Sam plans
to delay his return to the States by at least one day.


Regards,
Jim