1、Lessons Learned Entry: 0311Lesson Info:a71 Lesson Number: 0311a71 Lesson Date: 1994-02-03a71 Submitting Organization: JPLa71 Submitted by: P. W. SchaperSubject: STS-56 High Rate Data Channel Failure Impact to ATMOS Experiment Abstract: The high rate data channel for ATMOS failed. No complete end-to-
2、end test had been performed either prior to or after the flight. The recommendations point out the need for end-to-end testing (including tests to identify the failure mode before the payload is disassembled), pre-planned work arounds, and channels of communication from the PI to the mission manager
3、.Description of Driving Event: In April 1993, the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument was flown on board the space shuttle Discovery (STS-56) as part of the second Atmospheric Laboratory for Applications and Science (ATLAS-2) mission. While the instrument performed very well d
4、uring the mission, a very significant event occurred in the course of the flight, which could have resulted in little or no science data being returned from ATMOS. This problem also affected other experiments, but to a lesser degree. The problem involved the shuttles High Rate Data Telemetry System
5、and the SPACELABs High Data Rate Recorder (HDRR).Following payload subsystem activation, the ATMOS instrument was successfully powered up and performed the first operation - an engineering exercise to verify the proper operation of subsystems. The primary ATMOS science data stream is normally transm
6、itted live, or in a delayed record/dump mode on a high rate data channel. After only a few seconds of transmission the latter stream became extremely noisy and rendered the data scientifically unusable. Subsequently, NASA payload controllers attempted a work-around using the SPACELABs HDRR and the s
7、huttles Lower Data Rate Telemetry Channel. This method improved the data quality, but it still contained numerous parity errors.Fortunately, the ATLAS-2 mission was the first flight of a new, dedicated ATMOS recorder Provided by IHSNot for ResaleNo reproduction or networking permitted without licens
8、e from IHS-,-,-subsystem. This mission was originally intended to be an engineering evaluation and test flight for the recorder. The use of this recorder permitted the independent recording of more data than was needed to meet the minimum success criteria of the ATLAS-2 mission.No complete end-to-en
9、d test was performed, either prior to or after the flight. Following the mission, KSC performed several tests on the shuttle and SPACELAB telemetry system to determine the cause of the problem. No obvious failure mechanisms were found in either the orbiters system or in the spacelab subsystem. It ha
10、s only recently been learned, after several subsystem tests, that there were two or three problem areas in the STS-56 data system, which would explain the loss of data. From the point of view of the ATMOS experiment, the post-flight testing plans, organization, and execution were ineffectively coord
11、inated primarily because of a lack of a single authority figure to emphasize the importance of the testing activities to the success of the ATMOS experiment and the mission.The ATMOS experiment is described in some detail in SSEF # 1-104.Lesson(s) Learned: 1. End-to-end tests are essential to identi
12、fy complex system problems.2. When an in-flight failure occurs on a payload scheduled for reflight, it is essential that a satisfactory determination of the cause be accomplished prior to the disassembly of the payload.3. Functional redundancy is highly desirable for any single point failure subsyst
13、em.4. Investigations of the type described here require direction and coordination by a single authoritative person.Recommendation(s): 1. End-to-end tests must be performed.2. Ensure that end-to-end tests to determine failure modes are performed prior to the disassembly of the payload.3. If function
14、al redundancies for single point failure modes cannot be supplied, work arounds should be established before the start of the mission.4. In an STS payload involving experiments and instruments from different centers, the individual responsible for a given experiment must have the opportunity to appr
15、ise the mission manager of the importance of his/her experiment to overall mission success.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N/AMission Directorate(s): N/AAdd
16、itional Key Phrase(s): a71 Test & VerificationAdditional Info: Approval Info: a71 Approval Date: 1994-06-15a71 Approval Name: Carol Dumaina71 Approval Organization: 125-204a71 Approval Phone Number: 818-354-8242Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
