[IGSMAIL-0570] Block-1 est morte!
Tom
Tom
Mon Apr 18 10:47:47 PDT 1994
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IGS Electronic Mail Mon Apr 18 10:47:47 PDT 1994 Message Number 0570
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Author: Tom Clark
Subject: Block-1 est morte!
I don't know how many of you had noticed, but over the past ~ 10 days, the
DoD has deactivated all but one of the Block-1 satellites. Both PRN-3 and
PRN-13 have been showing unhealthy and transmitting bogus ephemerides. A few
minutes ago (06:00 UTC, 16 April) I checked and it appeared that PRN-3
(then at ~ 70 degrees elevation) was transmitting, but very weak. I have
not verified if PRN-13 has been transmitting in the past few days but it
was last weekend.
By my listings, this leaves PRN-12 as the only Block-1 satellite still
active. This unannounced event apparently happened about 10 days ago,
after the latest Block-2 satellite (PRN-6) was activated, which gave the
DoD a full operational constellation of 24 Block 2 satellites (PRN's
1,2,4,5,6,7,9,14 thru 29 and 31).
I was chatting with a knowledgeable DoD person late Friday and he confirmed
my observation. He indicated that the Block-1 satellites were too labor
intensive (i.e. expensive) to maintain and the DoD did not choose to keep
the tired old satellites operating with their reduced budgets. According
to him, any signals heard simply reflect end-of-life testing.
The last three Block-1 satellites are shown in the standard table, which
I have updated as follows:
NASA Orbit Launch
PRN Internat. Catalog Plane Date
SVN Code ID Number Pos'n (UT) Clock Available/Decommissioned
---------------------------------------------------------------------------
09 13 1984-059A 15039 C-1 84-06-13 Rb 84-07-19 thru 94-04-??
10 12 1984-097A 15271 A-1 84-09-08 Rb 84-10-03
11 03 1985-093A 16129 C-4 85-10-09 Rb 85-10-30 thru 94-04-??
This is a sad happening for those of us who liked having a few non-SA
satellites for clock synchronization. I saw no announcement of the Block-1
decommissioning -- did anyone?
Tom Clark
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