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Chapman, P. K.

Publications and source records attributed to Chapman, P. K..

14 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Power for Commercial Space Applications

Since the proposed space station is intended to be a permanent installation, used in part by commercial organizations, its design requirements differ fundamentally from those in previous manned spacecraft. In particular, commercialization on a significant scale depends critically on the ability to control capital and operational costs, including the cost of energy, and this demands new approaches to systems such as the power supply for the space station. These considerations suggest guidelines for power plant development. The cost of energy in space, guidelines for power supply development, quality standards, and the role of government are discussed.

Chapman, P. K.↗
NASA NTRS1980

Technology alternatives for the SPS

Emerging technologies may offer advantages over those selected for the reference design adopted for the SPS. While it is not possible to list all the technological innovations that may affect the SPS, it is feasible to develop a systematic methodology for assessing technical alternatives. This may be of value in evaluating proposed technologies and identifying high priority areas for research. Such a methodology includes involves (1) variation of guidelines; (2) analysis of system functions; (3) analysis of system sensitivity; (4) analysis of technology status and risk; and (5) external costs, problem areas, and criticisms of the SPS concept. The methodology is a first step towards the creation of a formal decision analytic framework which can support design choices and program decisions as development proceeds.

Glaser, P.↗
NASA NTRS1980

Encounters between SPS power beams and satellites in lower orbits

Interference between the solar power satellite (SPS) power beam and other satellites in lower orbits is described. Measures which might be taken to reduce the frequency of beam/satellite encounters or to minimize the effects of the encounters are discussed.

Chapman, P. K.↗
NASA NTRS1979

Assessment of economic factors affecting the satellite power system. Volume 2: The systems implications of rectenna siting issues

The feasibility was evaluated of finding potential sites for Solar Power Satellite (SPS) receiving antennas (rectennas) in the continental United States, in sufficient numbers to permit the SPS to make a major contribution to U.S. generating facilities, and to give statistical validity to an assessment of the characteristics of such sites and their implications for the design of the SPS system. It is found that the cost-optimum power output of the SPS does not depend on the particular value assigned to the cost per unit area of a rectenna and its site, as long as it is independent of rectenna area. Many characteristics of the sites chosen affect the optimum design of the rectenna itself.

Chapman, P. K.↗
NASA NTRS1977

Studies of orbital Eoetvoes experiments

A direct force-balance technique was analyzed for carrying out the Eoetvoes experiment in space, which is intended to give sufficient sensitivity to allow investigation of the gravitational interactions of energy stored in the weak interaction. The heart of experiment is an exceedingly sensitive dual accelerometer, containing two proof masses constructed of the materials whose Eoetvoes ratio is to be compared. For use in development of the accelerometer, a magnetic microbalance is proposed in which the weight of the proof mass is supported by magnetic forces which vary very slowly with the proof mass position. It is shown that at least two different mechanizations of the magnetic suspension may be feasible.

Chapman, P. K.↗
NASA NTRS1976

Laser absorption phenomena in flowing gas devices

A theoretical and experimental investigation is presented of inverse Bremsstrahlung absorption of CW CO2 laser radiation in flowing gases seeded with alkali metals. In order to motivate this development, some simple models are described of several space missions which could use laser powered rocket vehicles. Design considerations are given for a test call to be used with a welding laser, using a diamond window for admission of laser radiation at power levels in excess of 10 kW. A detailed analysis of absorption conditions in the test cell is included. The experimental apparatus and test setup are described and the results of experiments presented. Injection of alkali seedant and steady state absorption of the laser radiation were successfully demonstrated, but problems with the durability of the diamond windows at higher powers prevented operation of the test cell as an effective laser powered thruster.

Chapman, P. K.↗
NASA NTRS1972

Visual phenomena induced by cosmic rays and accelerated particles

Experiments, conducted at cyclotrons together with observations by Apollo astronauts, suggest with little doubt that cosmic nuclei interacting with the visual apparatus cause the phenomenon of light flashes seen on translunar and transearth coast over the past four Apollo missions. Other experiments with high and low energy neutrons and a helium ion beam suggest that slow protons and helium ions with a stopping power greater than 10 to the 8th power eV/gram sq cm can cause the phenomenon in the dark adapted eye. It was demonstrated that charged particles induced by neutrons and helium ions can stimulate the visual apparatus. Some approaches to understanding the long term mission effects of galactic cosmic nuclei interacting with man and his nervous system are outlined.

Tobias, C. A.↗
NASA NTRS1972

Observations of cosmic ray induced phosphenes

Phosphene observations by astronauts on flights near and far from earth atmosphere are discussed. It was concluded that phosphenes could be observed by the naked eye. Further investigation is proposed to determine realistic human tolerance levels for extended missions and to evaluate the need to provide special spacecraft shielding.

Chapman, P. K.↗
NASA NTRS1971

An Eotvos experiment in earth orbit

The gravitational interactions of mass energy stored in the weak interaction are being investigated. The magnitude of possible Eotvos anomalies, such as weak interaction, gravitational self-energy, spin-orbit interactions, and electromagnetic radiation reaction, are considered. A sensitive experiment was designed to determine whether weak interaction energy violates the equivalence principle. Factors to be considered in spacecraft design for the experiment are presented.

Chapman, P. K.↗
NASA NTRS1971

Light flash phenomenon seen by astronauts

The results from experiments conducted to characterize and elucidate light flashes seen by astronauts on Apollo 11, 12, 13, and 14 during transluna or transearth orbit are presented. The data show cosmic nuclei interacting with the visual apparatus causes the light flash phenomenon. The data also suggest that slow protons and helium ions with a stopping power greater than 10 KeV/micron will cause light flashes and streaks in the partially dark adapted eye. The effects of galactic cosmic nuclei interacting with man during long term missions are discussed.

Budinger, T. F.↗