Engineering topics

Nock, K. T.

Publications and source records attributed to Nock, K. T..

25 records · Page 2

NASA NTRS1979

Galileo Jupiter encounter and satellite tour trajectory design

The trajectory design process for the Galilean satellite probe, expected to be launched in January 1982, is examined and its interplanetary path, emphasizing arrival dates and the Mars flyby, is presented. The Galileo spacecraft is of dual spin design, combining features of Pioneer, a spinning craft, and Voyager which was 3-axis stabilized. The design of the initial orbit from Orbiter deflection through Jupiter to the beginning of the satellite tour is discussed as well as the use of an Io gravity assist flyby to achieve Jupiter orbit insertion, and the effects of solar perturbation on the initial orbit. Detail is given to the entire satellite tour trajectory design process, starting from the requirements and constraints placed on the tour through the conic design to the final numerically integrated trajectories.

Diehl, R. E.↗

NASA NTRS1979

Satellite aided orbit capture

The paper surveys the developments leading to the use of satellites for orbit control. Previous satellite gravity assist work is analyzed, emphasizing powered and unpowered aided capture schemes. In addition, a parametric study characterizes potential gains of satellite aided capture for various satellite systems. Finally, potential applications of aided capture such as for the Galilean System and for Saturn and Titan are given.

Nock, K. T.↗

NASA NTRS1977

Atmospheric braking to circularize an elliptical Venus orbit

The use of atmospheric drag to circularize an elliptical spacecraft orbit at Venus is analyzed parametrically for the Venus Orbital Imaging Radar Mission (VOIR) in 1983. Navigation, maneuver, and guidance requirements are discussed for the decay of a 24-hr orbit to a close circular orbit in about 30-60 days. A prototype 'Aerobrake' is described which is approximately 5 m in diameter and 25 kg in mass and which replaces a chemical retroengine of about 1300 kg in mass (delta V = 2.5 km/s) by a 700 kg in-orbit mass. The aerobrake, a light deployable Inconel sheet, shields the spacecraft from the flow and radiates the aerodynamic heating.

Mcronald, A. D.↗

NASA NTRS1977

Venus Orbital Imaging Radar mission analysis

Mission objectives for the Venus Orbital Imaging Radar (VOIR) project are outlined with attention to its scientific instrumentation. Design parameters of the SAR (Synthetic Aperture Radar) are described, including a high resolution capability of 200 m from a circular orbit of 375 km, which will be able to map the entire surface of the planet. Nineteen atmospheric experiments are foreseen, among them: CO2 stability assays, measurements of vertical mass transfer rates, observations of cloud circulation and composition, and an evaluation of solar wind effects on atmospheric dynamics. Navigation and orbital injection plans are reviewed, noting that the 1983 launch window (using STS) is optimum.

Nock, K. T.↗

NASA NTRS1976

Mariner mission to Encke 1980

Experimental design for the Mariner mission to Comet Encke is considered, examining the following experiments: volatile and nonvolatile chemical analysis, an imaging system for the comet nucleus, the ultraviolet spectrometer, and magnetic field and plasma experiments. Mission design is discussed, emphasizing the mission profile, trajectory and targeting and the spacecraft design.

Yeates, C. M.↗

NASA NTRS1975

Early Mariner comet flyby

An inexpensive first mission to a faint short period comet utilizing the spare Mariner Venus/Mercury spacecraft is studied with regard to science rationale and instrumentation and engineering feasibility and design. The spare Mariner spacecraft, suitably modified, is shown to be compatible with science requirements of a first comet flyby. Important aspects of this early mission would be penetration of the comet's gaseous coma and the approach of the nucleus to within hundreds of km in order to obtain in situ measurements and imaging that will help to establish comet science models and determine the hazards of a comet environment to future comet missions.

Nock, K. T.↗

NASA NTRS1972

Mariner Mars 1971 adaptive mission planning.

A formal mission-planning process was developed for the Mariner Mars 1971 missions to allow large-scale mission-plan changes based upon flight experience. A modular approach was taken to the definition of requirements and constraints for elements of the mission. A set of rules for combining these modules was established. The concept of a standard mission day was developed in order to provide a consistent time framework for operations. The resulting process allowed for major mission revisions after the failure of Mariner 8 and again after a dust storm had obscured Mars. It allowed adaptive science planning on a short-term turnaround basis throughout the mission.

Haynes, N. R.↗