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Hintz, G. R.

Publications and source records attributed to Hintz, G. R..

15 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Precision maneuver determination for trajectory corrections

The interplanetary navigation of a spacecraft requires precise calculation of trajectory correction maneuver parameters. Velocity increments must be found which make the required corrections, minimize propellant consumption, and do not violate hardware design constraints or scientific objectives. This process is illustrated by its application to the Galileo Mission. The paper describes inflight analysis techniques, mathematical modeling, and computational algorithms used in the precision maneuver calculation scenario.

Hintz, G. R.↗
NASA NTRS1985

Error analyses for the delivery of a spinning probe to Jupiter

The task of delivering the Galileo Probe to specified atmospheric entry conditions at Jupiter is especially challenging because tracking, trajectory corrections, and attitude adjustments are not possible after release of the Probe from the carrier vehicle. Statistical analysis of the spacecraft dynamics mapped into Probe dispersions in atmosphere-relative and relay-geometry parameters show that attitude stability, heating, and relay performance requirements can be satisfied. Reconstruction techniques are used to enhance estimates of the delivery parameters to permit correct interpretation of the scientific data for the Jovian atmosphere. A tradeoff which sacrifices some delivery accuracy and propellant is shown to guarantee satisfaction of a very tight reconstruction requirement for the trajectory considered in this report.

Hintz, G. R.↗
NASA NTRS1984

Design and analysis techniques for trajectory correction maneuvers

Selecting a spacecraft maneuver strategy usually involves tradeoffs of many competing factors. This paper describes such a tradeoff process. The method uses parametric data to cope with targeting requirements, thruster configuration and performance, hardware constraints, operational considerations, propellant optimization demands, and expected execution and orbit determination errors, while remaining flexible to react to new conditions.

Hintz, G. R.↗
NASA NTRS1980

An interplanetary targeting and orbit insertion maneuver design technique

The paper describes a tradeoff in selecting a planetary encounter aimpoint and a spacecraft propulsive maneuver strategy in the Pioneer Venus Orbiter Mission. The method uses parametric data spanning a region of acceptable targeting aimpoints in the delivery space and the geometric considerations. Real-time maneuver adjustments accounted for known attitude control errors, orbit determination updates, and late changes in a targeting specification.

Hintz, G. R.↗
NASA NTRS1979

Maneuver analysis

The maneuver design for Viking was accomplished in two phases. First, there was the preflight design and strategy development that was dictated by mission objectives and requirements. Orbit determination and maneuver execution accuracy statistics were used, together with propellant budget considerations, to determine specific maneuver requirements and strategies. The second phase of the maneuver design occurred in flight. The maneuver analyses that were performed in flight, the software that was employed, and the actual inflight results for the entire orbital phase of the nominal Viking Mission are described with emphasis on prelanding objectives and geometry considerations. The actual adaptive design and implementation of the maneuvers as the mission progressed are considered. This design process included the minimization of both propellant usage and the effects of maneuver execution errors, while complying with several mechanization constraints.

Mitchell, R. T.↗
NASA NTRS1979

Venus - Density of upper atmosphere from measurements of drag on Pioneer orbiter

Measurements of the changes in orbital period of the Pioneer Venus orbiter are used to estimate the density of the upper atmosphere of Venus at altitudes in the range from 150 to 200 km. At 150 km, the dayside mean density is 1.4 times 10 to the -13th g/cc and the nightside mean density is 4 times 10 to the -14th g/cc. The oscillatory patterns of density variation are described. The data for densities between 150 and 200 km on the dayside are sketchy but the data imply a scale height between 15 and 20 km.

Shapiro, I. I.↗
NASA NTRS1978

Orbit trim maneuver design and implementation for the 1975 Mars Viking Mission

The Viking Mission included the insertion of two unmanned spacecraft into orbit about Mars and the deployment of a soft-lander from each. A description is presented of the adaptive design and implementation of the spacecraft propulsive maneuvers as these flights progressed, taking into account also the inflight results for the orbital phase of the primary Viking mission. The design process included the selection of target parameters and the minimization of both propellant usage and the effects of execution errors, while complying with mission and operational constraints. All maneuvers performed to trim the spacecraft orbits are considered. Attention is given to navigation requirements, geometry definitions and terminology, maneuver mechanization and constraints, and maneuver capability.

Hintz, G. R.↗
NASA NTRS1974

Orbit trim strategies for the 1975 Mars Viking mission

Propulsive maneuver strategies have been developed for the Mars orbital phases of the Viking mission, including the activities before and after lander deployment. These strategies have been formulated as fixed sequences of orbit parameter-correction maneuvers which will be performed on specified spacecraft revolutions. Certain adaptive features are also available to ensure efficient use of propellants. Numerical simulations demonstrate that it is possible (to within a very high probability) to satisfy mission requirements on orbital navigation, using these strategies and Viking technology.

Hintz, G. R.↗
NASA NTRS1973

Maneuver analysis

The maneuver analysis for the Mariner 9 mission, both prelaunch and in-flight, was different from that of previous Mariners because of the requirement to insert the spacecraft into orbit about Mars and to trim the orbit to an unprecedented accuracy. The most apparent differences were in the spacecraft design, the software development, and the maneuver strategy required for each phase of the mission. The analysis that was performed and the software that was developed, with emphasis on the maneuver strategy and actual in-flight results are described.

Mitchell, R. T.↗
NASA NTRS1971

A Viking satellite orbit trim strategy

One strategy is submitted for meeting the varied and stringent requirements of the Viking Project on the control of the satellite orbit to obtain reconnaissance and to prepare for lander release. To satisfy these requirements, different orbit trim maneuver strategies were developed for two typical Viking missions. In addition, a summary of recent numerical results is included to show that this strategy satisfies the mission requirements which have been identified.

Hintz, G. R.↗