1、Lessons Learned Entry: 2257Lesson Info:a71 Lesson Number: 2257a71 Lesson Date: 2009-11-10a71 Submitting Organization: JPLa71 Submitted by: David Oberhettingera71 POC Name: Arthur F. Obenschain (OCO MIB Chair); Ralph Basilioa71 POC Email: arthur.f.obenschainnasa.gov; ralph.r.basiliojpl.nasa.gova71 PO
2、C Phone: 818-354-3228 (R. Basilio)Subject: Orbiting Carbon Observatory (OCO) Launch Vehicle Mishap Investigation Results Abstract: The February 2009 OCO mission failed to attain orbit aboard a Taurus launch vehicle, and the OCO satellite payload was lost. A mishap investigation board identified four
3、 potential causes that could have led to the failure: (1) failure of the Frangible Joint Subsystem, (2) insufficient electrical current to initiate the ordnance devices, (3) insufficient pressure supplied by the fairing pneumatic system, and (4) snagging of the Flexible Confined Detonating Cord. The
4、 board provided 11 related recommendations.Description of Driving Event: The Orbiting Carbon Observatory (OCO), an Earth orbiting satellite mission managed by the NASA/Caltech Jet Propulsion Laboratory, was designed to make precise, time-dependent, global measurements of atmospheric carbon dioxide (
5、CO2). On February 24, 2009, OCO failed to reach orbit aboard a Taurus launch vehicle, and the OCO payload and mission were lost. The proximate cause of the mishap was the failure of the Taurus payload fairing (Figure 1) to separate during ascent (Reference (1). A standard component of expendable lau
6、nch vehicles, a payload fairing is a clamshell-shaped cover that encloses and protects a payload on the pad and during early flight. The fairing is jettisoned when the launch vehicle has achieved an altitude where aeroheating of the payload is no longer a factor. The fairing should have been jettiso
7、ned shortly after Stage 2 ignition, but it remained attached for the remainder of the flight. Failure to shed the fairing mass prevented the satellite from attaining the orbital velocity needed to reach its planned orbit, Provided by IHSNot for ResaleNo reproduction or networking permitted without l
8、icense from IHS-,-,-resulting in atmospheric reentry and loss of the $260 million mission. Figure 1. Taurus Launch VehicleReferences: 1. “Overview of the Orbiting Carbon Observatory (OCO) Mishap Investigation Results For Public Release,“ MyNASA, July 16, 2009, http:/www.nasa.gov/pdf/369037main_OCOex
9、ecutivesummary_71609.pdf.Lesson(s) Learned: See “Recommendations“Recommendation(s): The findings of the NASA Mishap Investigation Board (MIB) for OCO that were not restricted as proprietary information, or as International Traffic in Arms Regulations (ITAR)-sensitive, were released as Reference (1).
10、 Although no flight hardware from the OCO mission was recoverable for examination, the MIB identified four potential causes that could have led to the failure, along with related recommendations: 1. Frangible Joint Subsystem failure caused fairing not to separate. It could not be determined if the f
11、rangible joint base ring fractured completely as designed. An incomplete fracture could have resulted in the fairing not separating. The MIB looked at the materials Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-used and their characteristics and re
12、commended: 1-1. Verify that the Taurus launch vehicle frangible joint extrusions have a traceable pedigree on future NASA missions. If pedigree cannot be verified, remove and replace the assigned hardware with frangible joints that have a complete pedigree. 1-2. Establish a single heat treat lot req
13、uirement for aluminum used to manufacture extrusion and perform sub-scale tests on the lot. 1-3. Institute permanent marking (which cannot be removed during processing) along the length of the extrusion at intervals to ensure traceability. 1-4. Implement a common procurement and assembly process for
14、 frangible joints used on the launch vehicle. 2. Electrical Subsystem failure caused fairing not to separate. It could not be determined if the transient bus supplied sufficient electrical current to initiate the required ordnance devices. Insufficient current could have resulted in an insufficient
15、quantity of ordnance devices firing, causing the fairing not to separate. The MIB recommended: 2-1. Scale (or rescale) launch vehicle telemetry to allow the transient power bus measurements to fully capture peak currents during flight. 2-2. Institute a process that monitors, captures, and analyzes P
16、ower Distribution Unit current output profiles during acceptance test and during flight simulations. 3. Fairing Pneumatic System failure caused fairing not to separate. It could not be determined if the fairing pneumatic system supplied sufficient pressure to separate the fairing. The fairing pneuma
17、tic system consists of the hot gas generator (HGG) system, thrusters, and pneumatic tubing. The MIB recommended: 3-1. Implement the following items into the HGG system. If the items cannot be fully implemented, then replace the HGG system with an alternate fairing jettison system that does not use a
18、 hot gas generator: a72 The HGG system should be qualified and acceptance tested in the flight-like configuration and environment. a72 Define and document the HGG sustainer grain propellant radiographic acceptance criteria, including the engineering rationale and applicability for using non-Taurus m
19、anufacturer criteria for the Taurus application. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a72 Modify the HGG design to retain small propellant pellets and preclude movement during dynamic environments. a72 Assure that HGG ignition occurs when
20、the HGG system is subjected to all induced thermal and dynamic environments. a72 Provide a controlled, verifiable, and repeatable means for mounting the HGG in the Taurus Launch Vehicle fairing for flight and for qualification and acceptance testing for flight.3-2. Demonstrate that the pressure cart
21、ridges initiation charge remains in contact with the bridgewire after being subjected to Taurus thermal and dynamic environments. 3-3. Establish functional performance requirements for pressure cartridges that screen for workmanship and lot-to-lot variability (i.e., time to first pressure, time to p
22、eak pressure and thermal time constant). 3-4. Assure manufacturing and inspection processes are consistent with the pressure cartridge design requirements.4. Flexible Confined Detonating Cord (FCDC) Snagged on Frangible Joint Side Rail Nut Plate. It could not be determined if the FCDC snagged on the
23、 frangible joint side rail nut plate, preventing the fairing from separating. The MIB recommended: 4-1. Route the FCDC, or implement a physical barrier, to exclude the possibility that the FCDC would snag on a nut plate cover.Evidence of Recurrence Control Effectiveness: JPL has referenced this less
24、on learned as additional rationale and guidance supporting Paragraph 4.2.3.1 (“Mechanical Configuration/Systems Design: Mechanisms - Deployment Systems Design Margin“) and Paragraph 7.1.2 (“Flight Scenario Design: Critical Sequence Telemetry Monitoring“) in the JPL standard “Design, Verification/Val
25、idation and Operations Principles for Flight Systems (Design Principles), JPL Document D-17868, Rev. 3,“ December 11, 2006.Documents Related to Lesson: N/AMission Directorate(s): Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a71 Sciencea71 Space Op
26、erationsa71 Exploration SystemsAdditional Key Phrase(s): a71 Program Management.Acquisition / procurement strategy and planninga71 Program Management.a71 Engineering Design (Phase C/D).a71 Engineering Design (Phase C/D).Launch Systemsa71 Engineering Design (Phase C/D).Powera71 Engineering Design (Ph
27、ase C/D).Spacecraft and Spacecraft Instrumentsa71 Manufacturing and Assemblya71 Additional Categories.Energetic Materials - Explosive/Propellant/Pyrotechnica71 Additional Categories.Accident Investigationa71 Additional Categories.a71 Safety and Mission Assurance.Qualitya71 Safety and Mission Assuran
28、ce.Product Assurancea71 Safety and Mission Assurance.a71 Additional Categories.Flight Equipmenta71 Additional Categories.Flight Operationsa71 Additional Categories.Hardwarea71 Additional Categories.Launch Vehiclea71 Additional Categories.Payloadsa71 Additional Categories.SpacecraftAdditional Info: a71 Project: Orbiting Carbon ObservatoryApproval Info: a71 Approval Date: 2010-01-14a71 Approval Name: mbella71 Approval Organization: HQProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
