CONTOUR Status Report August 2, 2002

CONTOUR continues operating nominally in its phasing
orbit. Five propulsive burns occured over the last week,
all of them executed very well. Three of the burns were
performed for changing the pointing of the spin axis. Two of the
burns were delta-v maneuvers. So far, there have been a total of
sixteen propulsive burns since launch, all of them have been
successful. With only two weeks to go before CONTOUR fires its
solid rocket motor, the mission operations team will spin up the
spacecraft to 60 rotations per minute, or rpm, on Monday, August 5.
The reason for spinning the spacecraft up to sixty rotations per
minute is to make it gyroscopically ‘stiff’ to lessen errors caused by
thruster misalignments, center-of-mass misalignments, and the
resulting nutation.

During ground testing, we spun up the spacecraft to 65 rpm on
three separate occassions as part of an effort to balance it and also
to confirm that the spacecraft was properly constructed to
withstand the centrifugal force generated by the spin. To do this,
the spacecraft was placed on a spin balance machine which
physically rotated the 2138 pound spacecraft. During electrical
testing, the solar array simulator was programmed to provide
electrical power into the spacecraft that mimicked a spacecraft
spinning at rates upto 120 rpm. We wanted to make sure that the
circuits that regulated the power did not create a lot of electrical
noise that could possiby disrupt spacecraft operation — they
didn’t.