1、Lessons Learned Entry: 0126Lesson Info:a71 Lesson Number: 0126a71 Lesson Date: 1992-08-24a71 Submitting Organization: KSCa71 Submitted by: Lisa L. MusgraveSubject: Environmental Control System (ECS) Hardware Interface Module (HIM) Card Description of Driving Event: Three Pad B ECS chillers condition
2、 air for the orbiter and payload changeout room. The ECS chiller GN2 control system, which regulates the amount of cooling provided by each chiller, is controlled by HIM 161 and HIM 213. The auto/direct mode select control allows chiller GN2 control via the auto or direct mode. Normally, HIM 161 con
3、trols chiller temperature/humidity in the automatic mode. If this mode should fail, chiller control is maintained by switching to the direct mode. If the HIM 161 direct mode fails, there is a potential for partial/total loss of chiller GN2 control and subsequent orbiter/payload damage.Lesson(s) Lear
4、ned: Failure of ECS HIM 161 card may cause loss of chiller GN2 control and result in high temperature/humidity damage to orbiter/payload.Recommendation(s): Design a remote back-up capability to allow chiller control from the redundant HIM 213 card in the event of HIM 161 failure.Evidence of Recurren
5、ce Control Effectiveness: N/AProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Documents Related to Lesson: N/AMission Directorate(s): a71 Space Operationsa71 Exploration SystemsAdditional Key Phrase(s): a71 HardwareAdditional Info: Approval Info: a71 Approval Date: 1994-06-02a71 Approval Name: James G. Klinea71 Approval Organization: KSC/HEIa71 Approval Phone Number: 407-867-7614Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
