News by Date
News by Category
Solar System
Stars
White Dwarfs
Supernovas
Neutron Stars
Black Holes
Milky Way Galaxy
Normal Galaxies
Quasars
Galaxy Clusters
Cosmology/Deep Field
Miscellaneous
Press Resources
Status Reports
Press Advisories
Image Releases
Release Guidelines
Image Use Policy
NASA TV
Biographies/Interviews
Web Shortcuts
Chandra Blog
RSS Feed
Chronicle
Email Newsletter
News & Noteworthy
Image Use Policy
Questions & Answers
Glossary of Terms
Download Guide
Get Adobe Reader
Chandra @ NASA
Visit the Chandra pages at the NASA portal (opens in new window)
Image Use
Image Use Policy & Request Form
Guidelines for utilizing images, applets, movies, and animations featured in this Web Site.
Operations CXO Status Report

Monday 27 September 1999 7.00am EST

During the last 24 hours the spacecraft experienced a bright star hold and safe mode event. Following trouble shooting and assessment, the spacecraft was returned from safe mode to normal Sun mode and readied for the next eclipse scheduled at 12:30PM 9/27. The ACIS was commanded to the next-in-line position for radiation belt passage. During the safe mode entry and recovery to normal sun mode the spacecraft performed as expected.

The spacecraft entered bright star hold at 9AM 9/26 following a maneuver with a large attitude error due to an incorrect quaternion in the command load. Safe mode entry occurred at 6:57PM 9/26 following an operator error during fine attitude initialization to recover from bright star hold. Safe mode recovery to normal Sun mode was completed at 4:10AM 9/27. Full analysis is being performed on the sequence of events leading to safe mode, however initial assessment indicates modifications to flight and ground software and ground procedure are required.

Following fine attitude initialization, the plan is to re-intercept the GTO observing plan after appropriate load review and procedure revision.





Return to Status Reports