1、Lessons Learned Entry: 1122Lesson Info:a71 Lesson Number: 1122a71 Lesson Date: 1999-02-01a71 Submitting Organization: HQa71 Submitted by: David M. LengyelSubject: Aero-Space Technology/X-34 In-Flight Separation from L-1011 Carrier Description of Driving Event: Validation of Flight Software for X-34
2、and L-1011 Carrier Aircraft Flight SeparationLesson(s) Learned: The X-34 technology demonstrator program faces safety risks related to the vehicles separation from the L-1011 carrier aircraft and to the validation of flight software. Moreover, safety functions seem to be distributed among the numero
3、us contractors, subcontractors, and NASA without a clear definition of roles and responsibilities.Recommendation(s): NASA should review and assure that adequate attention is focused on the potentially dangerous flight separation maneuver, the thorough and proper validation of flight software, and th
4、e pinpointing and integration of safety responsibilities in the X-34 program.Evidence of Recurrence Control Effectiveness: Wind tunnel separation tests simulating the separation of the X-34 from the L-1011 have been successfully completed, using scale wind tunnel models of the X-34 and L-1011. The X
5、-34 release mechanism is based on the flight-proven Pegasus release mechanism designed by Orbital Sciences Corporation. The A-1 vehicle will be flown in captive carry mode under the L-1011; additionally, the A-2 vehicle will be flown in dress rehearsal attached to the L-1011.The aerodynamic forces a
6、nd flying qualities of the combined vehicles will be assessed during these flights.The flight software will be carried through a thorough Verification and Validation testing process by Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Orbital Sciences
7、Corporation. Performance tests of the X-34 navigation system (hardware and flight software) have already been conducted at the White Sands Missile Range using an aircraft platform. Subjecting the flight software to IV and V remains an option to the program if concerns about the software dictate. In
8、May 1998, Code Q conducted a detailed review of safety and mission assurance processes being used by the X-34 program, and found the existing processes in place at Orbital Sciences Corporation and its subs to be satisfactory. Recommendations from the review have been addressed, and are available for
9、 review. A follow-up review with Code Q and the X-34 Project Office was held on December 10, 1998.Documents Related to Lesson: N/AMission Directorate(s): a71 Exploration Systemsa71 Aeronautics ResearchAdditional Key Phrase(s): a71 Administration/Organizationa71 Aerospace Safety Advisory Panela71 Air
10、crafta71 Computersa71 Policy & Planninga71 Risk Management/Assessmenta71 Softwarea71 Spacecrafta71 Test & VerificationAdditional Info: Approval Info: a71 Approval Date: 2002-02-12a71 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-,-,-
