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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.

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At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Mission Analysis Program for Solar Electric Propulsion (MAPSEP). Volume 2: User's manual for earth orbital MAPSEP

The trajectory simulation mode (SIMSEP) requires the namelist SIMSEP to follow TRAJ. The SIMSEP contains parameters which describe the scope of the simulation, expected dynamic errors, and cumulative statistics from previous SIMSEP runs. Following SIMSEP are a set of GUID namelists, one for each guidance correction maneuver. The GUID describes the strategy, knowledge or estimation uncertainties and cumulative statistics for that particular maneuver. The trajectory display mode (REFSEP) requires only the namelist TRAJ followed by scheduling cards, similar to those used in GODSEP. The fixed field schedule cards define: types of data displayed, span of interest, and frequency of printout. For those users who can vary the amount of blank common storage in their runs, a guideline to estimate the total MAPSEP core requirements is given. Blank common length is related directly to the dimension of the dynamic state (NDIM) used in transition matrix (STM) computation, and, the total augmented (knowledge) state (NAUG). The values of program and blank common must be added to compute the total decimal core for a CDC 6500. Other operating systems must scale these requirements appropriately.

Source record↗
NASA NTRS1975

Apollo experience report: Engineering and analysis mission support

The tasks performed by the team of specialists that evaluated hardware performance during prelaunch checkout and in-flight operation are discussed. The organizational structure, operational procedures, and interfaces as well as the facilities and software required to perform these tasks are discussed. The scope of the service performed by the team and the evaluation philosophy are described. Summaries of problems and their resolution are included as appendixes.

Fricke, R. W., Jr.↗
NASA NTRS1976

Maximization of orbiter altitude at ALT interface airspeed, mission planning, mission analysis and software

The determination of the separation initial conditions (i.e. incidence angle) that maximize orbiter altitude at the ALT interface airspeed is considered. Optimum altitude airspeed profiles are generated for each orbiter incidence angle and tailcone configuration. Results show that the highest separation altitude does not result in the highest altitude at ALT interface airspeed. The altitude attainable at ALT interface airspeed should therefore be considered in the selection of the initial conditions (i.e. incidence angle). Without violating any known constraints, the incidence angles that maximize orbiter altitude at the ALT interface airspeeds are 7.0 deg for ALT free flight 1 and 5.5 deg for ALT free flight 6.

Glenn, G. M.↗
NASA NTRS1976

Proposed powered explicit guidance thrust integrals derivation/implementation. Mission planning, mission analysis and software formulation

A new exoatmospheric, powered explicit guidance (PEG) thrust integral formulation and a simple method of implementation are presented. The new thrust integral formulation is significantly simpler than that currently used in PEG. Preliminary estimates indicate a computer storage savings of 220 words, which is approximately 10 percent of the current PEG ascent program. Alternate methods of implementation that could produce even more savings are noted.

Jaggers, R. F.↗
NASA NTRS1976

Orbiter/carrier separation for the ALT free flight no. 1 reference trajectories. Mission planning, mission analysis and software formulation

Details of the generation of the separation trajectories are discussed. The analysis culminated in definition of separation trajectories between physical separation and orbiter/carrier vortex clearance. Specifications, assumptions and analytical approach used to generate the separation trajectories are presented. Results of the analytical approach are evaluated. Conclusions and recommendations are summarized. Supporting references are listed.

Glenn, G. M.↗
NASA NTRS1976

Orbiter altitude at ALT interface based on ALSES (Approach and Landing Shuttle Engineering Simulation) analyses. Mission planning, mission analysis and software formulation

The details of the orbiter altitude attainable at the approach and landing tests (ALT) interface determined by the approach and landing shuttle engineering simulation (manned) were documented. The analysis culminated in the verification of the trends observed in a similar analysis performed previously on the space vehicle dynamics simulation (unmanned). Altitude variations attributable to pilot steering variability ranged between 492 ft higher to 383 ft lower. The requirement for this parametric analysis is first elaborated. The specifications, assumptions, and analytical approach used to determine the orbiter altitude at the ALT interface are then presented, followed by the results of the analytical approach and the conclusions and recommendations.

Colwell, C. L.↗
NASA NTRS1976

Mission analysis to define satellite orbits for earth radiation budget measurements

Information is presented concerning the number of satellites, the orbit altitude, and the inclinations which will provide the spatial and temporal earth coverage required for accurate radiation measurements on regional, zonal, and global scales. Measurement considerations are discussed and an analysis is conducted regarding the selection of suitable orbit parameters. Attention is also given to the results of a simulation model study for the determination of the radiation which can be measured by satellite sensors in different orbits.

Harrison, E. F.↗
NASA NTRS1977

Space shuttle engineering and operations support. ALT separation reference trajectories for tailcone on orbiter forward and aft CG configurations. Mission planning, mission analysis and software formulation

A preflight analysis of the ALT separation reference trajectories for the tailcone on, forward, and aft cg orbiter configurations is documented. The ALT separation reference trajectories encompass the time from physical separation of the orbiter from the carrier to orbiter attainment of the maximum ALT interface airspeed. The trajectories include post separation roll maneuvers by both vehicles and are generated using the final preflight data base. The trajectories so generated satisfy all known separation design criteria and violate no known constraints. The requirement for this analysis is given along with the specifications, assumptions, and analytical approach used to generate the separation trajectories. The results of the analytical approach are evaluated, and conclusions and recommendations are summarized.

Glenn, G. M.↗
NASA NTRS1977

Smoothing of orbital tracking data: Mission planning, mission analysis and software formulation

The problem created by the presence of wild or outlying data points among orbital tracking data, is addressed. Consideration is given to the effects of such outliers on the orbit determination process, and methods for minimizing or even eliminating these effects are proposed. Some preliminary efforts implementing these new methods are described, and the results thus far obtained are summarized. Based on these ideas and results, recommendations are made for future investigation.

Vedder, J. D.↗
NASA NTRS1979

Modifications to give HOPE/MDC 2.0 the capability to solve for or consider vent forces: Mission planning, mission analysis, and software formulation

The modifications are described as necessary to give the Houston Operations Predictor/Estimator (HOPE) program the capability to solve for or consider vent forces for orbit determination. The model implemented in solving for vent forces is described along with the integrator problems encountered. A summary derivation of the mathematical principles applicable to solve/consider methodology is provided.

Zyla, L. V.↗
NASA NTRS1978

Photovoltaic mission analysis

Photovoltaic analysis was used to support the planning, development, and guidance of the National Photovoltaic program. The analysis identified and evaluated: (1) photovoltaic applications likely to have major energy impact; (2) appropriate strategies for stimulating the growth of photovoltaic markets; and (3) critical issues, define scope of subsequent examinations.

Leonard, S. L.↗
NASA NTRS1982

Mission analysis techniques for attached Shuttle payloads

Visibility times, i.e., times which desired targets are visible to a payload, are examined for attached Shuttle payloads. These times are affected by a number of constraints. Some constraints are examined along with mathematical or computer modeling techniques used to determine their effects. The constraints include: occultation of the earth, moon, and sun, and limb avoidance angles of each; orbit parameters such as inclination and ascending node, along with sensitivity to changes in each; TDRSS acquisition; South Atlantic Anomaly (SAA) avoidance, nighttime viewing only; bright earth avoidance angles; the field of view; Shuttle attitude, and Orbiter operational constraints. All of this information is integrated and, with computer programs, a schedule of observations and Shuttle attitudes is obtained.

Lambros, S.↗