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Lyons, D.

Publications and source records attributed to Lyons, D..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2001

Aerobraking automation options

This paper will summarize some recent work to automate most of the commanding intensive activities associated with aerobraking.

aerobraking↗
NASA NTRS1999

Mars Pathfinder Project: Planetary Constants and Models

This document provides a common set of astrodynamic constants and planetary models for use by the Mars pathfinder Project. It attempts to collect in a single reference all the quantities and models in use across the project during development and for mission operations.

Mars Pathfinder Planetary Constants↗
NASA NTRS1998

Mars Global Surveyor: Aerobraking Mission Overview

The Mars Global Surveyor spacecraft was launched on November 6, 1996 and was captured into a highly elliptical, 45 hour orbit around Mars with a 973 m/s propulsive maneuver on September 12, 1997.

aerobraking↗
NASA NTRS1996

Aerobraking at Mars: The MGS Mission

The Mars Global Surveyor (MGS) mission, scheduled for launch in November 1996, will employ aerobraking as a means of reaching a low altitude, sun-synchronous mapping orbit. This technique is necessary to minimize the cost of the mission. The dry mass of the spacecraft and the launch vehicle capability do not permit an all-propulsive transfer to the desired orbit. Aerobraking concepts are discussed.

Mars↗
NASA NTRS1994

Spaceborne Photonics Institute

This report describes in chronological detail the development of the Spaceborne Photonics Institute as a sustained research effort at Hampton University in the area of optical physics. This provided the research expertise to initiate a PhD program in Physics. Research was carried out in the areas of: (1) modelling of spaceborne solid state laser systems; (2) amplified spontaneous emission in solar pumped iodine lasers; (3) closely simulated AM0 CW solar pumped iodine laser and repeatedly short pulsed iodine laser oscillator; (4) a materials spectroscopy and growth program; and (5) laser induced fluorescence and atomic and molecular spectroscopy.

Venable, D. D.↗
NASA NTRS1989

The Magellan Venus mapping mission

The April 1989 Magellan (MGN) Mission to Venus will initiate a new phase in the exploration of the solar system. In addition to being the first U.S. planetary mission in 10.5 years, it will also be the first such mission to use the Space Shuttle and IUS 2-Stage as launch vehicles. Upon arrival at Venus the spacecraft will begin a systematic mapping of the surface of that planet using side-looking SAR. This paper discusses some of the interesting trade-offs in mission design for this mission in the areas of launch and injection, interplanetary cruise, Venus Orbit insertion, and mapping. The Magellan mapping strategy is discussed briefly along with a few special experiments being considered for the MGN extended mission.

Cutting, E.↗
NASA NTRS1975

The dominant mode of standing Alfven waves at the synchronous orbit

Low-frequency oscillations of the earth's magnetic field recorded by a magnetometer on board ATS 1 have been examined for the 6-month interval between January and June 1968. Using evidence from OGO 5 and ATS 5 as well as the data from ATS 1, it is argued that the dominant mode at ATS 1 must be the fundamental rather than the second harmonic of a standing Alfven wave. It is concluded that these transverse oscillations are more accurately associated with magnetically disturbed days than with quiet days. From 14 instances when oscillations of distinctly different periods occurred during the same time interval at ATS 1, it is also concluded that higher harmonics can exist. The period ratio in seven of the 14 cases corresponds to the simultaneous occurrence of the second harmonic with the fundamental, and four other cases could be identified as the simultaneous occurrence of the fourth harmonic with the fundamental.

Cummins, W. D.↗
NASA NTRS1975

The dominant mode of standing Alfven waves at synchronous orbit

Low-frequency oscillations of the earth's magnetic field recorded by the UCLA magnetometer on board ATS-1, have been examined for the six-month interval, January-June, 1968. The initial interpretation, that these oscillations represent the second harmonic of a standing Alfven wave, has been re-examined, and it is concluded that this hypothesis must be withdrawn. Using evidence from OGO-5 and ATS-5, as well as the data from ATS-1, it is argued that the dominant mode at the synchronous orbit must be the fundamental rather than the second harmonic. From 14 instances when the oscillations of distinctly different periods occurred during the same time interval at ATS-1 it is concluded that higher harmonics can exist. The period ratio in 7 of the 14 cases corresponds to the simultaneous occurrence of the second harmonic with the fundamental, and 4 other cases could be identified as the simultaneous occurrence of the fourth harmonic with the fundamental.

Cummings, W. D.↗