1、Lessons Learned Entry: 1240Lesson Info:a71 Lesson Number: 1240a71 Lesson Date: 2002-06-17a71 Submitting Organization: HQa71 Submitted by: David LengyelSubject: International Space Station/Command & Data Handling/System Stability and Control Methods Description of Driving Event: International Space S
2、tation Command & Control Computer crashes due to common cause failure mode.Lesson(s) Learned: The Command & Data Handling System (C&DH) system is vulnerable to instability under heavy load conditions. This problem is currently handled by procedurally controlling processing activities.Recommendation(
3、s): Process outstanding Problem Reports (PRs). Evaluate potential architectures that would improve system stability and robustness and ensure safe operations. Implement architecture improvements as soon as it is prudent to do so. Evidence of Recurrence Control Effectiveness: Believe this has already
4、 been accomplished as part of the standard design and development activities. Believe this has already been accomplished as part of the standard design and development activities. Due to the large amount of ISS SW code being developed and in use, there is an imposing amount of Problem Report traffic
5、. The backlog varies based on the amount of testing in progress at any one time. Considerable emphasis is being placed on reduction of the backlog and a dedicated team has been instituted as a part of the I&O contract to focus solely on PR resolution. Results to date indicate that even though the to
6、tal backlog varies up and down relative to current activities, the average age of the open PRs is decreasing. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Preliminary work has already been done to identify improvement areas. As Pre-Planned Product
7、 Improvement funding becomes available, we will move forward to implement any appropriate enhancements. Documents Related to Lesson: N/AMission Directorate(s): a71 Space Operationsa71 Exploration SystemsAdditional Key Phrase(s): a71 Aerospace Safety Advisory Panela71 Computersa71 Configuration Manag
8、ementa71 Flight Operationsa71 Research & Developmenta71 SoftwareAdditional Info: Approval Info: a71 Approval Date: 2002-06-27a71 Approval Name: Bill Loewya71 Approval Organization: HQa71 Approval Phone Number: 202-358-0528Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
