An Open Letter To:
Bernhard Fleck, Chief Scientist, ESA/SOHO
Monday, December 28th, 1998
I trust that your holidays are going well, and that you will enjoy the advent of the approaching New Year 1999. The Christmas holiday was well placed in time this year as it temporarily diverted our attention from what appears to be a very confusing, if not down right mysterious, set of circumstances, coupled with long periods of complete silence, regarding the operational status of the SOHO satellite, or "SOHO Interruptus III". For example there hasn't been even a tiny peep from the SOHO/LASCO/NASA/ESA combine regarding the health of this billion dollar plus satellite since December 22; a period of six days.
We are also wondering if you could explain a whole
series on what seem to be contradictory terms, and/or
explanations, which were
followed today by a historical revision of the official LASCO Daily Status Log so that it now contains what I think is my only encounter with a triple compound non sequitour.
A brief recapitulation is in order:
1.0 LASCO Daily Status Log announces a Emergency Sun Requisition (ESR) event that began at 12/21/98 17:49 UT. We have been taught by SOHO/LASCO that these ESR's are on-board computer controlled procedures that happen automatically when the satellite looses its lock on the Sun. An ESR is very serious maneuver, because we have been further told that the satellite has only 45 to 60 minutes of battery back up if the solar panels are not facing the Sun. This is what is alleged to have happened causing the June 25, 1998 black out.
2.0 The very same day, December 21, 1998, the "SOHO What's New"
"SOHO is in safe mode. The spacecraft entered safe mode today at 17:49 UT.Preliminary indications are that the remaining gyro may have failed."
So on one page we have and "Emergency Sun Requisition 17:49 UT", and on another page we have a "Safe Mode 17:49 UT" without further explanation to date.
3.0 On December 22, 1998 the LASCO Daily Status Log reports:
"22-Dec.-1998 S/C Hold In ESR Mode; LASCO/EIT Low Rate TLM Only; No Obs"
The obvious question here is how does one "hold" in an emergency position?
4.0 And again on the same day as the above "SOHO What's New" reports:
December 22, 1998
"SOHO is in safe mode and will remain in it until new flight software for gyroless operations is implemented. Therefore, there will not be any scientific observations for the time being."
5.0 From Dec. 22 through Dec. 27 the LASCO Daily Status Log reported:
"S/C Hold In ESR Mode; LASCO/EIT Low Rate TLM Only; No Obs"
6.0 Today Dec. 28 the LASCO Daily Log, back to and including Dec 22, 1998, has been altered to read:
"S/C Hold In ESR Safe Mode;
LASCO/EIT Low Rate TLM Only; No Obs"
So we are now being told that the status of the magnificent SOHO/LASCO satellite is:
****"Hold In Emergency Sun Requisition Safe Mode."****
Please Bernhard, can someone in your multi-billion dollar operation speak some simple truth about the status of SOHO/LASCO? It would be greatly appreciated.
Very truly yours,
Earl L. Crockett
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