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At least 19 records

The JPL telerobot operator control station: Operational experiences

The Operator Control Station of the JPL/NASA Telerobot Demonstration System provides an efficient man-machine interface for the performance of telerobot tasks. Its hardware and software have been designed with high flexibility. It provides a feedback-rich interactive environment in which the Operator performs teleoperation tasks, robotic tasks, and telerobotic tasks with ease. The to-date operational experiences of this system, particularly related to the Object Designate Process and the Voice Input/Output Process are discussed.

Kan, Edwin P.

Magellan spacecraft team remote mission operations - Experience and application to future operations systems

The Magellan Venus radar mapping mission was NASA's first planetary launch in 11 years, heralding a successful return to unmanned planetary exploration. This paper first describes the spacecraft, its mission, and its Mission Operations System, including the remotely located spacecraft team. It then discusses how the flight team achieved mission success, in spite of the obstacles imposed by challenges from the spacecraft and its environment, which had to be resolved with the spacecraft team nearly 1000 miles distant from the rest of the flight team. Benefits of remotely distributed spacecraft operations are summarized and suggestions offered, based on Magellan experience, for future mission operations systems considering the use of distributed elements.

Ledbetter, Kenneth W.

NASA/ESA CT-990 Spacelab simulation. Appendix A: The experiment operator

A joint NASA/ESA endeavor was established to conduct an extensive spacelab simulation using the NASA CV-990 airborne laboratory. The scientific payload was selected to perform studies in upper atmospheric physics and infrared astronomy with principal investigators from France, the Netherlands, England, and several groups from the United States. Two experiment operators from Europe and two from the U.S. were selected to live aboard the aircraft along with a mission manager for a six-day period and operate the experiments in behalf of the principal scientists. This appendix discusses the experiment operators and their relationship to the joint mission under the following general headings: selection criteria, training programs, and performance. The performance of the proxy operators was assessed in terms of adequacy of training, amount of scientific data obtained, quality of data obtained, and reactions to problems that arose in experiment operation.

Reller, J. O., Jr.

Stirling machine operating experience

Numerous Stirling machines have been built and operated, but the operating experience of these machines is not well known. It is important to examine this operating experience in detail, because it largely substantiates the claim that Stirling machines are capable of reliable and lengthy lives. The amount of data that exists is impressive, considering that many of the machines that have been built are developmental machines intended to show proof of concept, and were not expected to operate for any lengthy period of time. Some Stirling machines (typically free-piston machines) achieve long life through non-contact bearings, while other Stirling machines (typically kinematic) have achieved long operating lives through regular seal and bearing replacements. In addition to engine and system testing, life testing of critical components is also considered.

Ross, Brad

Stirling machine operating experience

Numerous Stirling machines have been built and operated, but the operating experience of these machines is not well known. It is important to examine this operating experience in detail, because it largely substantiates the claim that Stirling machines are capable of reliable and lengthy lives. The amount of data that exists is impressive, considering that many of the machines that have been built are developmental machines intended to show proof of concept, and were not expected to operate for any lengthy period of time. Some Stirling machines (typically free-piston machines) achieve long life through non-contact bearings, while other Stirling machines (typically kinematic) have achieved long operating lives through regular seal and bearing replacements. In addition to engine and system testing, life testing of critical components is also considered.

Ross, Brad A.

Space Shuttle operations experience

Lessons learned from Shuttle operations are discussed with emphasis placed on: (1) reusability of flight systems, (2) orbiter ground turnaround, (3) flight design, (4) payload integration, and (5) training. Attention is also given to the impact of the Challenger accident on Shuttle operations. Operations experience in flight design, payload integration, and flight controller and astronaut training reveals that initial projections underestimated the compexity, time, and manpower required. This can be attributed to the demands of customizing each mission to maximize the science return in a shrinking Shuttle flight program, and to frequent changes of the cargo manifest to optimize the mix of science and applications payloads.

Gunn, Charles R.

Some Operating Experience and Problems Encountered During Operation of a Free-jet Facility

During a free-jet investigation of a 28-inch ram-jet engine at a Mach number of 2.35, flow pulsation at the engine inlet were discovered which proved to have an effect on the engine performance and operational characteristics, particularly the engine rich blowout limits. This report discusses the finding of the flow pulsations, their elimination, and effect. Other facility characteristics, such as the establishment of flow simulation and the degree of subcritical operation of the diffuser, are also explained.

Mcaulay, John E

Operational experiences of a commercial helicopter flown in a large metropolitan area

A survey of commercial helicopter-operating experiences was conducted using a helicopter flight recorder in order to provide a basis for extending helicopter design and service-life criteria. These data are representative of 182 flight hours accumulated during 1414 flights comprised of the separate legs of the total route structure employed. The operating experiences are presented in terms of the time spent within different airspeed brackets, within the classifiable flight conditions of climb, en route, and descent, at various rates of climb and descent, and at different rotor rotational speeds. The results indicated that the helicopter spent a majority of the flight time at airspeeds either below 40 knots or above 100 knots. Rates of climb and descent were concentrated at values below 5.1 m/s (1000 ft/min) particularly for higher airspeeds. Normal acceleration experiences were low, both in the total number and peak value realized; however, an extremely large number of pitch angular-velocity experiences were noted. Rotor rotational speeds were normal with no occurrences above the upper red-line limit.

Dicarlo, D. J.

A database containing operational experience in spaceflight

A relational data base, called the Operational Experience Data Base, was constructed to electronically store and organize human-factors information from the Skylab and Space Shuttle missions. The taxonomy used to organize this data base builds on the one used for the Skylab human-machine experiments. This information can be used by NASA engineers and operations personnel to remedy design problems, or expand on design successes. Work to improve and expand the data base is underway.

Callaghan, Thomas

International Space Station Operational Experience and Its Impacts on Future Mission Supportability

Operational experience gained on the International Space Station (ISS) has enabled significant improvements in failure rate estimates for various Orbital Replacement Units (ORUs). These improved estimates, in turn, allow more efficient and accurate spare parts allocations for future missions, enabling significant reductions in both logistics mass and risk. This paper examines the value of ISS experience to date in terms of its impact on supportability for future missions. A supportability model is presented that assesses the spares required as a function of mission endurance and risk, taking into account uncertainty in failure rate estimates. Changes in ISS Environmental Control and Life Support (ECLSS) ORU failure rate estimates are described and discussed, both in terms of the overall population of ORUs and the evolution of failure rate estimates over time for a particular item. The value of those updated failure rate estimates is assessed by calculating the estimated spares mass requirements for two cases, using the initial, pre-ISS estimates and using the estimates informed by on-orbit experience. Hidden risk resulting from underestimated failure rates is also assessed. These results indicate that, for a 1,200-day Mars mission, ISS experience has enabled a 3.9 t to 6.0 t reduction in ECLSS spares mass required and uncovered failure rate underestimates that would have resulted in an order of magnitude increase in risk had they not been discovered and corrected. The implications of these results for system development and mission planning are discussed, including approaches to accelerate the rate of failure rate refinement and the risks associated with making changes or introducing new systems. Overall, test time is a critical factor that must be carefully considered in system development, and new systems must budget appropriate time for testing in a relevant environment or accept higher risk and logistics requirements on future missions.

Owens, Andrew C.

Operating experiences of retardant bombers during firefighting operations

Data are presented on operational practices and maneuver accelerations experienced by two Douglas DC-6B airplanes converted to retardant bombers and used in firefighting operations. The data cover two fire seasons in the mountainous regions of the northwestern United States.

Jewel, J. W., Jr.