[amsat-bb] AO-40 Update, S1 Tx Stopped

["Stacey E. Mills" <w4sm@xxxxxxxxxx>]

On orbit 362 at MA 57 (2001-08-13,  12:57:53 UTC), while AO-40 was in view 
of most of the eastern hemisphere,  the S1 transmitter abruptly stopped 
transmitting part way through an A-blk.  Telemetry readings up until the 
moment of cessation (voltages, currents, temperatures, etc.) were 
completely normal.  No commanding or experimentation was being done at this 
time.

The scheduler switched the S2 on as appropriate at MA=100.  Telemetry after 
MA=100, likewise shows no abnormalities or logged events to account for 
this failure.

An initial attempt to manually switch the S1 Tx back on did not appear 
successful.    While we study this situation further, the  S1 Tx has been 
taken out of the schedule.  Thus, the U/L1 -> S2 passbands are currently 
active from MA 10-30 and MA 44-100.  As before, RUDAK is connected  to the 
S2 Tx (beacon off) from MA=30-44.

The message blocks have not yet been updated.  This will be done within the 
next several orbits.  The schedule may also be modified for longer passband 
periods, given the broader coverage of the S2 helical antenna.

As further information becomes available, we will post it here

--- W4SM for the AO-40 Command Team




--
  _______________________________________________________________________
  Stacey E. Mills, W4SM    WWW:    http://www.cstone.net/~w4sm/ham1.html
   Charlottesville, VA     PGP key: http://www.cstone.net/~w4sm/key
  _______________________________________________________________________

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