SEARCH · Search NASA
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
The off-scale low indications of the voltmeters for batteries one and two at initial powerup of the Apollo 16 lunar roving vehicle were analyzed. No single condition was found that would explain the anomalous meter indications. It is concluded that the intermittent conditions must have existed in the multiple wire splices to the meters.
Explore the source record for details and available documents.
There were two investigative aspects associated with the loss of the cryogenic oxygen tank pressure during the Apollo 13 flight. First, what was the cause of the flight failure of cryogenic oxygen tank 2. Second, what possible contributing factors during the ground history of the tank could have led to the ultimate failure in flight. The first flight indication of a problem occurred when the quantity measurement in the tank went full scale about 9 hours before the incident. This condition in itself could not have contributed to ignition in the tank, since the energy in the circuit is restricted to about 7 milli-joules. Data from the electrical system provided the second indication of a problem when the fans in tank 2 were activated to reduce any stratification which might have been present in the supercritical oxygen in the tank. Several short-circuits were detected and have been isolated to the fan circuits of tank 2. The first short-circuit could have contained as much as 160 joules of energy, which is within the current-protection level of the fan circuits. Tests have shown that two orders of magnitude less energy than this is sufficient to ignite the polytetrafluoroethylene insulation on the fan circuits in the tank. Consequently, the evidence indicates that the insulation on the fan wiring was ignited by the energy in the short-circuit.
Failure analysis of recovery flasing xenon lamp on Apollo 10 flight
High gain antenna acquisition problem during Apollo 13 flight
Analysis of anomalous jettisoning of service module during reentry of Apollo 11
The command module reaction control system is emptied of all remaining propellant using ground support equipment designed to provide an acid/base neutralization of the propellant in both the liquid and gaseous phases so that it may be disposed of safely. During the deactivation operation of the oxidizer from the Apollo 16 command module on 7 May 1972, the scrubber tank of the decontamination unit exploded, destroying the ground support equipment unit and damaging the building that housed the operation. Only minor injuries were received by the personnel in the area and the command module was not damaged. Test results show that the failure was caused by an insufficient quantity of neutralizer for the quantity of oxidizer. This insufficiency lead to exothermic nitration-type reactions which produced large quantities of gas at a very high rate and failed the decontamination tank.
The report by the Apollo 16 crew that the lunar roving vehicle rear steering was inoperative during the initial drive from the vehicle's deployment site was investigated. The malfunction, and the steering system are described. It is concluded that an open circuit occurred either in the hand controller potentiometer or between the potentiometer wiper and the summing node.
An explosive failure of a ground support equipment decontamination unit tank occurred during the postflight deactivation of the oxidizer (nitrogen tetroxide) portion of the Apollo 16 command module reaction control system. A discussion of the significant aspects of the incident and conclusions are included.
Results are presented of analyses conducted to determine why erroneous data were transmitted by 60 of the 1 sample-per-second telemetry channels of Apollo 17 for a 2-minute period beginning at about 191 hours 40 minutes. Reasons for the failure and corrective actions taken are described.
Approximately 2 minutes 13 seconds after lift-off of the Apollo 6 mission, abrupt changes of strain, vibration, and acceleration measurements were indicated in the S-IVB, instrument unit, adapter, lunar module, and command and service modules; photographs showed objects coming from the area of the adapter. The adapter, however, continued to sustain the required loads with no impairment of the mission. The investigation was first focused upon the understanding of the coupled vibration modes and characteristics of the launch vehicle and spacecraft.' Extensive test programs were conducted. It was eventually concluded that the adapter failure was not caused by vibration. Extensive study of the airborne photography and other evidence indicated that a large area of the adapter had lost inner facesheet from the honeycomb sandwich panels. Loads and stresses resulting from vibration were determined to be insufficient to initiate such a failure. The investigation was then directed toward determining the range of pressures that could have been trapped in the Apollo 6 adapter sandwich panels, and toward determining the tolerance of the panels to withstand pressure with various degrees of flaws such as adhesive voids and facesheet dents. The degradation effects of moisture and heat exposure on the adhesive strength were also studied and tested. These tests and analyses led to the conclusion that pressure internal to the sandwich panels could have caused the failure, if a large flaw existed. The pressure buildup would have been caused by aerodynamic heating effects on air and moisture trapped in the panel. The probable cause of the failure was found in the original ultrasonic inspection scan record of the affected adapter panel. In the center of the region where the adapter failed, horizontally along the station 709 panel splice, the record contained two thick anomalous lines extending several feet. Without an X-ray record of this region, the significance of this particular scan record cannot be fully understood. However, since all other evidence had indicated that the adhesive had to be weakened in a rather large area to initiate the failure, the investigation was focused intently upon the station 709 splices of other adapters. Sufficient information was developed to verify that deficient assembly techniques have consistently resulted in abnormalities in the structure at this station. These abnormalities were identified in adapters 12, 13, 14, 15, and 16. Before the splice abnormalities were pinpointed, corrective action was taken to reduce pressure "buildup in the honeycomb panels and to reduce heat degrading effects on the adhesive. This was done by drilling vent holes in the inner facesheet and covering the outer facesheet with cork. The adapters having identified abnormalities in the station 709 splice are being repaired, and the contractor is investigating ways of avoiding these -abnormalities in panels yet to be bonded.
This NASA Unmanned Flight Anomaly Report analyzes reported anomalies related to the in-flight performance of mechanisms on Jet Propulsion laboratory (JPL) unmanned space programs.
The various postflight reports prepared by the mission evaluation team, including the final mission evaluation report, report supplements, anomaly reports, and the 5-day mission report, are described. The procedures for preparing each report from the inputs of the various disciplines are explained, and the general method of reporting postflight results is discussed. Recommendations for postflight documentation in future space programs are included. The official requirements for postflight documentation and a typical example of an anomaly report are provided as appendixes.
The significant anomalies that occurred during the Apollo 15 mission are discussed. The five major areas are command and service modules, lunar module, scientific instrument module experiments, Apollo lunar surface experiment package and associated equipment, and government furnished equipment.
The significant anomalies that occurred on the Apollo 16 flight are presented. The major areas under which failures and anomalies are identified are: (1) command and service modules, (2) lunar module, (3) government-furnished equipment, lunar surface experiments, and orbital experiments. All times shown are elapsed time from range zero, established as the integral second before lift-off. Diagrams and photographs of equipment are included to clarify written explanations.
The significant anomalies that occurred during the Apollo 17 mission are investigated. The discussion is divided into five major sections: command and service modules, lunar module, government-furnished equipment, lunar surface experiments, and orbital experiments. All times are elapsed time from range zero, established as the integral second before lift-off.
This report summarizes and updates the annual on-orbit performance between January I and December 31, 1994, for spacecraft built by or managed by the Goddard Space Flight Center (GSFC). During 1994, GSFC had 27 active orbiting satellites and I Shuttle-launched and retrieved 'free flyer.' There were 310 reported anomalies among 21 satellites and one GSFC instrument (TOMS). GOES-8 accounted for 66 anomalies, and SAMPES reported 155 'anomalies'. Of the 155 anomalies reported for all but SAMPEX, only 4 affected the spacecraft missions 'substantially' or greater, that is, presented a loss of more than 33% of the total missions. The most frequent subsystem anomalies were Instrument/Payload(44), Timing Command and Control(40), and Attitude Control Systems(33). Of the non-SAMPEX anomalies, 29% had no effect on the missions and 28% caused subsystem or instrument degradation and, for another 28%, no anomaly effect on the mission could be determined. Fifty-three percent of non-SAMPEX anomalies could not be classified according to 'type'; the other most common types were 'systemic'(35), 'random'(19), and 'normal or expected operation'(15). Forty percent of the anomalies were not classified according to failure category; the remaining most frequent occurrences were 'design problems'(50) and 'other known problems'(35).
Thee unmanned planetary spacecraft to the outer planets have been controlled and operated successfully in space for an accumulated total of 66 years. The Voyager 1 and 2 spacecraft each have been in space for more than 26 years. The Galileo spacecraft was in space for 14 years, including eight years in orbit about Jupiter. During the flight operations for these missions, anomalies for the ground data system and the flight systems have been tracked using the anomaly reporting tool at the Jet Propulsion Laboratory. A total of 3300 incidents, surprises, and anomaly reports have been recorded in the database. This paper describes methods and results for classifying and identifying trends relative to ground system vs. flight system, software vs. hardware, and corrective actions. There are several lessons learned from these assessments that significantly benefit the design and planning for long life missions of the future. These include the necessity for having redundancy for successful operation of the spacecraft, awareness that anomaly reporting is dependent on mission activity not the age of the spacecraft, and the need for having a program to maintain and transfer operation knowledge and tools to replacement flight team members.