1、Lessons Learned Entry: 1713Lesson Info:a71 Lesson Number: 1713a71 Lesson Date: 2005-11-11a71 Submitting Organization: JPLa71 Submitted by: David Oberhettingera71 POC Name: Ralph Basilioa71 POC Email: Ralph.R.Basiliojpl.nasa.gova71 POC Phone: 818-354-3228Subject: Simulate the Launch Site RF Configura
2、tion During I&T Abstract: Science data losses during compatibility testing at the CloudSat launch site were traced to an RF cabling configuration that differed from the cables, couplers, and attenuators used during I&T. Simulate the launch (or launch support) facility cabling configuration during I&
3、T, and consider performing the actual launch control function from within the factory I&T facility as a standard practice.Description of Driving Event: A Factory Compatibility Test (FCT) was performed on the NASA CloudSat spacecraft to provide a baseline for comparison of payload function and perfor
4、mance after transportation to and installation at the launch pad. In May 2005 a Launch Base Compatibility Test (LBCT) was performed at Vandenberg Air Force Base (VAFB). The LBCT ground support equipment (GSE) configuration differed significantly in complexity from that of the FCT (as described below
5、). The LBCT was performed in the payload processing facility (PPF) to verify the compatibility of CloudSat radio frequency (RF) signals with the Air Force Satellite Control Network (AFSCN) ground system. Examination of the LBCT results showed that approximately 5 percent of the science data frames d
6、ownlinked from the Cloud Profiling Radar instrument aboard CloudSat failed to reach the Vandenberg Tracking Station (VTS). After significant resources were expended troubleshooting this problem under launch schedule pressure, the anomaly was traced to the test configuration differences between the F
7、CT and the Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-LBCT. For the spacecraft RF signal to reach the VTS, it must pass through a series of GSE coaxial cables, couplers, and attenuators in the PPF. Subsequent modifications to match the FCT confi
8、guration resulted in an increase in signal strength of 10-20 dB, and the number of lost science data frames was reduced significantly below specified levels. An effective industry practice is to duplicate the launch control at the factory or at the system-level spacecraft test, or Assembly, Test, an
9、d Launch Operations (ATLO), facility. This is done with sufficient fidelity and configuration control to assure that anomalous conditions encountered at the launch site may be efficiently and thoroughly analyzed and resolved during integration and test (I&T). Highly successful space programs, includ
10、ing some recent JPL missions, have taken further steps to assure launch and deployment success by conducting primary launch and/or deployment operations at the “factory,“ or within the ATLO facility itself. The operations facilities at the launch site are then reserved for use only as a backup. Refe
11、rences: (1) “LBCT CPR Data Loss,“ JPL Incident Surprise Anomaly (ISA) No. Z86739, June 10, 2005. (2) CloudSat Mission Readiness Review, “Spacecraft“ section, September 1, 2005. (3) “End-to-End Compatibility and Mission Simulation Testing,“ NASA Reliability Preferred Practice for Design and Test No.
12、PT-TE- 1437 (NASA Lessons Learned No. 0726), February 1, 1999.Lesson(s) Learned: It is a standard JPL factory ATLO practice to duplicate the power and signal cabling configuration that will be encountered at the launch site, and to evaluate any changes to other launch site GSE that are too complex f
13、or simulation during ATLO. Violations of this “Test as you fly“ practice may result in significant RF signal degradation and data loss during subsequent launch site compatibility testing or during flight.Recommendation(s): 1. Simulate the launch (or launch support) facility cabling configuration at
14、the NASA or contractor ATLO facility as part of system I&T. Once verified, monitor the cabling configuration at the launch facility to assure that any changes are identified. Where launch facility changes have been made, or where ATLO simulation of launch facility GSE is not feasible, evaluate such
15、elements for payload impacts and possible risks well before the commencement of compatibility testing at the launch site. 2. To ensure the compatibility of the as-tested system with launch facilities, consider performing the complete launch control function from within the factory ATLO facility as a
16、 standard practice for uncrewed Earth orbit or deep space missions, with control facilities at the launch site reserved as a backup.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Evidence of Recurrence Control Effectiveness: JPL opened Preventive Ac
17、tion Notice (PAN) No. Z87781 on November 11, 2005 to initiate and document appropriate Laboratory-wide action on the above recommendations.Documents Related to Lesson: N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Additional Categories.a71 Additional Categories.Communication Systemsa71
18、 Additional Categories.Configuration Managementa71 Additional Categories.Facilitiesa71 Additional Categories.Flight Equipmenta71 Additional Categories.Flight Operationsa71 Additional Categories.Ground Equipmenta71 Additional Categories.Ground Operationsa71 Additional Categories.Hardwarea71 Additiona
19、l Categories.Launch Processa71 Additional Categories.Payloadsa71 Additional Categories.Range Operationsa71 Additional Categories.Spacecrafta71 Additional Categories.Test Articlea71 Additional Categories.Test FacilityAdditional Info: a71 Project: CloudSata71 Year of Occurrence: 2005Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval Info: a71 Approval Date: 2006-06-30a71 Approval Name: tmasona71 Approval Organization: HQProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
