Engineering topics

Wellman, J. B.

Publications and source records attributed to Wellman, J. B..

23 records · Page 2

NASA NTRS1978

Onboard processing for future space-borne imaging systems

There is a strong rationale for increasing the rate of information return from imaging class experiments aboard both terrestrial and planetary spacecraft. Future imaging systems will be designed with increased spatial resolution, broader spectral range and more spectral channels (or higher spectral resolution). The data rate implied by these improved performance characteristics can be expected to grow more rapidly than the projected telecommunications capability. One solution to this dilemma is the use of improved onboard data processing. The use of onboard classification processing in a multispectral imager can result in orders of magnitude increase in information transfer for very specific types of imaging tasks. Several of these processing functions are included in the conceptual design of an Infrared Multispectral Imager which would map the spatial distribution of characteristic geologic features associated with deposits of economic minerals.

Wellman, J. B.↗

NASA NTRS1976

Planetary imaging - Past, present, and future

Recent exploration of the planets has been highlighted by the development of visual imaging systems carried on board the spacecraft. This paper describes the evolution of planetary camera systems from the earliest reconnaissance flight to Mars in 1965 (Mariner 4) through the planned mission to Jupiter and Saturn in 1977. Advances in telecommunication performance, mission planning and operations, and digital processing of images are also discussed. Science objectives and changes in the imaging systems required to meet these objectives are discussed for the Mariner Mars 1971 (Mariner 9), Mariner Venus-Mercury (Mariner 10), Viking 1975 (Mars Orbiter), and Mariner Jupiter-Saturn 1977 missions. The last section of the paper describes future plans for imaging experiments based on cameras using solid-state sensors, particularly charge-coupled devices.

Masursky, H.↗

NASA NTRS1976

The Viking Orbiter Visual Imaging Subsystem

Two Viking spacecraft each consisting of an Orbiter and a Lander are on trajectories toward Mars with arrival dates in June and August 1976. A Visual Imaging Subsystem consisting of two slow-scan television cameras forms part of the scientific payload of each Orbiter. These cameras will be used to evaluate the potential landing sites on Mars and to conduct other scientific investigations of the planet. The camera system described in this paper was subjected to an extensive test and calibration program prior to launch. Based on this calibration and subsequent analyses, absolute photometric accuracies of 8.0% may be achieved. Surface resolution exceeding 100 meters will be achieved from the periapsis portion of the Viking orbits. The inherent geometric accuracies of the Orbiter cameras supersede those of previous planetary missions. The analyses of images acquired during the cruise phase of the mission confirms that the cameras have survived the rigors of launch and are performing in a manner consistent with the prelaunch calibrations.

Wellman, J. B.↗

NASA NTRS1972

Transonic divider for gas chromatograph effluents

Transonic effluent divider system was developed which permits varying mass input of gas chromatographic effluent into mass spectrometer without affecting performance of gas chromatograph. Mechanisms of operation are described.

Wellman, J. B.↗

NASA NTRS1968

Compact rotating cup anemometer

Compact, collapsible rotating cup anemometer is used in remote locations where portability and durability are factors in the choice of equipment. This lightweight instrument has a low wind-velocity threshold, is capable of withstanding large mechanical shocks while in its stowed configuration, and has fast response to wind fluctuations.

Wellman, J. B.↗