Engineering topics

Holt, A. C.

Publications and source records attributed to Holt, A. C..

6 records

NASA NTRS1986

Electromagnetic braking for Mars spacecraft

Aerobraking concepts are being studied to improve performance and cost effectiveness of propulsion systems for Mars landers and Mars interplanetary spacecraft. Access to megawatt power levels (nuclear power coupled to high-storage inductive or capacitive devices) on a manned Mars interplanetary spacecraft may make feasible electromagnetic braking and lift modulation techniques which were previously impractical. Using pulsed microwave and magnetic field technology, potential plasmadynamic braking and hydromagnetic lift modulation techniques have been identified. Entry corridor modulation to reduce loads and heating, to reduce vertical descent rates, and to expand horizontal and lateral landing ranges are possible benefits. In-depth studies are needed to identify specific design concepts for feasibility assessments. Standing wave/plasma sheath interaction techniques appear to be promising. The techniques may require some tailoring of spacecraft external structures and materials. In addition, rapid response guidance and control systems may require the use of structurally embedded sensors coupled to expert systems or to artificial intelligence systems.

Holt, A. C.↗

NASA NTRS1981

Crew optimized Shuttle/experiment pointing

The extensive participation of the Shuttle crewmembers (Commander, Pilot, Mission Specialist, and Payload Specialist) in Shuttle/experiment pointing is required to accomplish and enhance payload pointing operations and to optimize associated data collection. For payloads requiring extensive pointing operations, the degree of mission success which can be achieved by the involvement of the crew can not be matched by a combination of remote ground operations and automation. The importance of the use of the crew's manipulative skills, scientific judgment, and flexibility in the alteration of preplanned time lines was clearly demonstrated during the Skylab Apollo Telescope Mount solar experiment operations. The payload pointing operations associated with the Spacelab Instrument Pointing System and the Annular Suspension and Pointing System Gimbal System will also extensively use these crew capabilities. Crew operations will also play a potentially important role in the use of advanced pointing systems to accurately point experiments which have an extensive interaction with the surrounding environment, such as laser experiments.

Holt, A. C.↗

NASA NTRS1980

Prospects for a breakthrough in field-dependent 'propulsion'

If sufficient justification exists to start the development of a field physics laboratory, attention might well be given to the development of two advanced types of field-independent propulsion systems. These are gravimagnetic systems and field resonance systems. The first are multipurpose propulsion systems employing the 'gravitational' effects of coherent electromagnetic energy configurations. The second are deep-space propulsion systems which artificially generate an energy pattern that matches precisely, or resonates with, a virtual pattern associated with a distant space-time point. A new model of space-time/field interactions is used in the present paper to describe the potential characteristics of electromagnetic/gravitational field interactions and the performance capabilities of these two propulsion systems.

Holt, A. C.↗

NASA NTRS1980

Hydromagnetics and future propulsion systems

Futuristic hydromagnetic propulsion systems for spacecraft are examined with emphasis on systems that use regular coherent patterns of magnetic and electric fields of very high strength to interact with the structure of space-time to effect a quick translation from one space-time point to another. A particular type of this system is discussed: namely, the field resonance propulsion concept which will utilize superconducting magnets and a configuration of tunable free-electron lasers.

Holt, A. C.↗

NASA NTRS1979

Field resonance propulsion concept

A propulsion concept was developed based on a proposed resonance between coherent, pulsed electromagnetic wave forms, and gravitational wave forms (or space-time metrics). Using this concept a spacecraft propulsion system potentially capable of galactic and intergalactic travel without prohibitive travel times was designed. The propulsion system utilizes recent research associated with magnetic field line merging, hydromagnetic wave effects, free-electron lasers, laser generation of megagauss fields, and special structural and containment metals. The research required to determine potential, field resonance characteristics and to evaluate various aspects of the spacecraft propulsion design is described.

Holt, A. C.↗

NASA NTRS1977

Skylab simulator visual displays and training for joint observing programs

The complexity of the Skylab Apollo Telescope Mount (ATM) experiment operations necessitated the use of high fidelity simulations of the onboard visual displays and pointing system for crew training. The displays which were simulated included the H-alpha displays, XUV monitor display, XUV/slit/white light display, X-ray image display, and the white light coronagraph display. The pointing simulation was achieved by projecting film sequences which were subsequently viewed by TV cameras. An optical system in front of the vidicons simulated the pointing, roll, and zoom capabilities of the ATM and sensing systems. The simulation enabled the Skylab crewmen to obtain valuable integrated training combining such tasks as target recognition and status assessment, complex and the time dependent pointing operations, malfunction analyses, and rapid responses to flare and other transient events.

Holt, A. C.↗