Saturday 30 July 1999 7.00am EST
|The Chandra mission continues to proceed nominally.
The following is an overview of the events that occurred over the last 24 hours:
Another series of Earth Sensor scan and IRU bias dwell measurements were successfully completed.
An ACIS Event Histogram was successfully performed. All tests performed to date on the ACIS indicate that the instrument is operating exceptionally well.
The daily vacuum monitor reading was 1.5 x 10EE-5 torr, which continues to follow the pressure profile experienced during the Chandra thermal vacuum test.
Checkout activities of the HRC Imaging and spectroscopic detectors continued. HRC high voltage on the Spectroscopic plates was brought up to only 1550 volts; since pressure in the instrument remains above the value that would allow the voltage to be brought to its operating level, 1750 volts. All other tests on the instrument were nominal. The HRC IPI has decided to not attempt an additional turn on of high voltage for about five days, or until the vehicle vacuum gage indicates further reductions in internal pressure.
Activities planned for the next 24 hours includes:
Activities will be initiated to prepare for uploading the On-orbit software, writing over the launch software load in the Interface Unit EEE Prom. Currently Chandra's onboard software contains functions that are needed only for the deployment and transfer orbit activities. The on-orbit software load is designed to support long term on-orbit operations. The on-orbit software will be loaded into the IU and verified. The software will then be loaded into the onboard computer after arriving at the operational orbit.
ACIS Internal Calibrations will continue.
Future Significant Activities:
IPS Burn #3 is scheduled for 6:30pm EDT July 31. This is a perigee burn to raise apogee to the nominal 140,000kms while leaving perigee at the current 3460 km.
Note: the Chandra Operations Chief will transmit Subsequent submittals of this report.
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