QUESTION:
I understand that you think the Lander's clock may now be set incorrectly,
because the Lander's rechargeable batteries have now reached the end of
their useful life, and the so it may be trying to communicate at an
unexpected time of the day. Would it therefore be possible to reserve a
portion of the Deep Space Network to listen/transmit to the Lander for
relatively large slabs of time, say most/all of one day - otherwise you
might be missing the signals?  Even if some portions of the day had to be
missed, they could be filled in on subsequent days.

ANSWER from Bridget Landry on November 25, 1997:
Several things:

1) we have already tried this, on a more limited scale, and not  heard
anything

2) in addition to timing  the transmit/receive sessions, the clock  is
also used to know where to point the high gain antenna; this cannot be
corrected by listening at other times

3) other problems exist--we believe  the extreme cold has changed  the
frequencies at which  the s/c is  transmitting and receiving,  thus we
have to scan in different frequencies, as well as different times

4) since we are no longer on our prime mission, other projects have  a
higher priority for time on  the DSN, particularly MGS, which  is just
starting its main mission and is having to alter its aerobraking plans

Thanks for your interest and ideas!

Bridget Landry
Deputy Uplink System Engineer
Mars Pathfinder Project