1、Lessons Learned Entry: 1090Lesson Info:a71 Lesson Number: 1090a71 Lesson Date: 1993-03-05a71 Submitting Organization: GSFCa71 Submitted by: Joseph R. Duke / Eric RaynorSubject: Pegasus/SCD 1 Launch Anomaly Review Committee Final Report of March 1993 Abstract: An apparent momentary dropout of the Com
2、mand Destruct Receiver initiated an abort during the launch of a Pegasus vehicle.The lesson offers 10 recommendations (dealing mostly with mission rules, launch constraints, and communications) to prevent similar incidents in the future and improve overall range operations.Description of Driving Eve
3、nt: During the launch of the Pegasus/SCD 1 on February 9, 1993, an incident occurred in the final minute of the countdown where an abort was initiated by the Wallops Flight Facility (WFF) Range Safety Officer (RSO); however, the operation continued with the launch of the Pegasus vehicle.At T minus 0
4、:59, the WFF/RSO initiated an abort due to an apparent momentary dropout of the Command Destruct Receiver (CDR). The abort call was picked up by the WFF Test Director (TD), who immediately enunciated the abort, at T minus 0:56 and T minus 0:47. The countdown clock was stopped at T minus 0:52 seconds
5、 and was not restarted until Pegasus release at T minus 0:00. A contractor Test Conductor (TC) announced the abort at T minus 0:44, and the abort was passed by NASA 1 to the B-52 at approximately T minus 0:34. The B-52 crew replied that the fin batteries were on and that they understood the abort. F
6、ollowing this discussion, the contractor TC rescinded the abort call, and NASA 1 passed the negative on the abort to the B-52 at T minus 0:22. The Pegasus vehicle was then dropped from the B-52 near T minus 0:00 time.Key WFF personnel in the Range Control Center (RCC) were not expecting the drop due
7、 to the abort call. However, the drop was observed on video, the alert was sounded that Pegasus had been launched, and all supporting personnel and stations responded immediately. Their timely response Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
8、allowed the successful completion of this mission. At no time during the flight was the ability to destruct the Pegasus jeopardized.Lesson(s) Learned: The Review Committee concluded that the primary cause for this incident was that the Range Safety abort was rescinded without on net authority and ra
9、nge awareness. The principal contributing factors to this incident were the off net communications; and confusion that resulted from having two separate operational nets, the lack of sufficiently detailed and attended prelaunch briefings, and the lengthy process of communicating with the B-52.The Re
10、view Committee during its investigation has compiled a list of findings and conclusions. They have been grouped in the following categories:1. Abort Process2. Mission Rules3. Communications4. Launch Day Roles and Responsibilities5. Mission Planning and PreparationABORT PROCESSFINDINGS1. An abort was
11、 initiated by the WFF/RSO, the abort was rescinded by the contractor TC without on net authority and range awareness.2. The B-52 was required to reduce altitude just prior to the CDR dropout abort call.3. WFF, Eastern Range (ER), Merritt Island Tracking Station (MILA) and Bermuda Tracking Station (B
12、DA) responded in a manner which allowed continued flight of the Pegasus after launch4. There was no procedure in the WFF/OSD or the Contractor Launch Checklist (LC) that detailed the procedure for rescinding an abort.CONCLUSIONSFrom the above findings, the Committee reached the following conclusions
13、:1. The contractor TC method of rescinding the abort was inadequate.2. Fin battery actuation was a consideration in the decision to rescind the abort.3. The altitude problem may have contributed to the confusion concerning the abort.4. Capability to destruct the Pegasus was maintained throughout the
14、 flight.5. Quick positive reaction by all supporting personnel allowed this flight to continue to a Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-successful conclusion.MISSION RULESFINDINGS1. An apparent dropout of a Flight Termination System (FTS)
15、 CDR occurred. This apparent dropout required an abort of the launch according to the mission rules.2. Not all key personnel were aware of all mission rules. Additionally, in some cases, key personnel had different interpretations of mission rules.CONCLUSIONS1. There were misunderstandings among key
16、 personnel concerning the mission rules. Lack of awareness and misinterpretation of mission rules may have contributed to this incident.2. The FTS CDR dropout mission rule produced a high risk of mission abort. The complex routing of the data stream (vehicle/aircraft to ground, ground to Time Divisi
17、on Multiple Access (TDMA) satellite, satellite to ground) and the amount of support equipment necessary to provide this data (decoms, bit syncs, cabling) produced a high probability of data loss not related to CDR health.COMMUNICATIONSFINDINGS1. No single Intercom Channel (IC) was understood by all
18、key participants as the primary launch net.2. The WFF/RSO chain of communication to the B-52 required 3 intermediaries.3. The configuration of communication equipment used by NASA 1 and the contractor TC was operationally awkward.4. Formal intercom net protocol was not consistently used.CONCLUSIONS1
19、. The lack of a single IC for all critical calls that was monitored by all key personnel contributed to confusion and to the ranges lack of knowledge of impending launch.2. The chain of communication between the WFF/RSO and the B-52 contained too many elements.3. Improved intercom net discipline may
20、 have prevented misunderstandings leading to the unplanned launch.4. The contractor TC had expected to receive Range abort calls from the WFF/RCO on IC 4. The fact that the abort was only transmitted on IC 1 by the WFF/TD and heard off net by the Provided by IHSNot for ResaleNo reproduction or netwo
21、rking permitted without license from IHS-,-,-contractor TC caused the contractor TC to question the abort call and delayed the passing of the abort to the B-52.LAUNCH DAY ROLES AND RESPONSIBILITIESFINDINGS1. There were no clear lines of authority and responsibility for launch decisions.2. The OSC/TC
22、 rescinded the abort command without proper on net authority and range awareness.CONCLUSIONS1. The primary cause of this incident was that the OSC/TC rescinded the abort without on net authority and range awareness. The lack of clear lines of authority and responsibility contributed to his/her actio
23、ns.2. The limited abort scenarios exercised during the dress rehearsal were not sufficient to identify all authority and responsibility conflicts.MISSION PLANNING AND PREPARATIONFINDINGS1. No pre-launch briefing was held at which all key participants reviewed mission rules, constraints, and procedur
24、es.2. The WFF/Operations and Safety Directive (OSD) and the Contractors Launch Operations and Mission Constraints (LOMC) document contained conflicting information that was not completely integrated in the mission planning process.3. A complete dress rehearsal was not conducted for this mission.CONC
25、LUSIONS1. The pre-mission planning and preparation process was inadequate for a mission of the scope and complexity of the Pegasus / SCD-1 launch.2. Conflicting Information in the various organizations documentation may have contributed to this incident.3. The lack of a pre-mission briefing attended
26、 by all organizations that reviewed roles, responsibilities, mission rules/constraints, IC assignments, and the launch decision process contributed to this incident.Recommendation(s): Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Based on the findi
27、ngs and conclusions, the Committee identified the following recommendations which should prevent similar incidents in the future and improve overall range operations:1. Management for both the Range User and the Range should ensure that the roles and responsibilities of critical decision making pers
28、onnel are clearly defined and understood.2. The Range User and the Range should establish, document, and fully coordinate all mission rules and launch constraints.3. A final pre-mission briefing should be conducted as near the intended launch date as possible (1 to 2 days before launch). All key par
29、ticipants should be represented at this briefing. This briefing should include but not be limited to: a. Roles and responsibilities of all key participants and the launch decision processb. Mission rules and launch constraintsc. Operational procedures including standard abort/hold terminologyd. Comm
30、unication channels assignments and protocol4. A direct link should be provided (either voice or electronic) from the WFF RSO/TD to the flight crew that enables the WFF RSO/TD to hold the launch in the latter stages of the count should an abort/hold condition arise.5. The terminal countdown should be
31、 conducted on a single communications net. All critical mission status calls should be made on this net.6. The FTS CDR mission rule should be reviewed.7. All inflight non-reversible countdown items such as battery activation should be preceded by a “go for“ command.8. Video from carrier and/or chase
32、 aircraft is a highly desirable source of information and should be provided for all future missions.9. Prior to launch, various scenarios should be conducted that exercise abort calls from the various mission support elements.10. A dress rehearsal which exercises as many assets as possible should b
33、e conducted prior to each launch. There should be a recovery day between dress rehearsal and launch.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Mission Directorate(s
34、): N/AAdditional Key Phrase(s): a71 Administration/Organizationa71 Aircrafta71 Air-Traffic Managementa71 Communication Systemsa71 Configuration Managementa71 Flight Equipmenta71 Flight Operationsa71 Human Factorsa71 Launch Processa71 Logisticsa71 Mishap Reportinga71 Policy & Planninga71 Range Operat
35、ionsa71 SpacecraftMishap Report References: Pegasus / SCD 1 Launch Anomaly Review Committee Final Report of March 1993Additional Info: Approval Info: a71 Approval Date: 2002-02-12a71 Approval Name: Jay Liebowitza71 Approval Organization: GSFCa71 Approval Phone Number: 301-286-4467Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
