Universal structure of measurement-induced information in many-body ground states
Not provided.
Materials Science↗
Engineering topics
Potter, Andrew
Publications and source records attributed to Potter, Andrew.
A Small, Remotely Operated, Coronagraph located at Small Observatory to obtain Frequent Low-cost Remote Observations of the Lunar Exosphere
The sodium in the lunar exosphere is a marker for the study of the lunar exosphere because the sodium possesses two strong resonance transitions from the ground state whose wavelengths fall in the visible spectrum near 590 nm. Emissions at these wavelengths are thus, observable from Earth. Observations have shown that the exosphere responds in a complex way to the external processes (impact vaporization, sputtering, and photon stimulated desorption) that weather the lunar regolith to produce the sodium (Sarantos et aI., Icarus, 205, 2010). Unraveling the sodium production allows us to study the processes that weather the regolith. Obtaining the extensive time sequence of observations required to unravel the sources of sodium using conventional observatories is impractical, and too expensive. Effectively imaging the lunar sodium exosphere close to the Moon requires an off-axis rejection of scattered light that can only be obtained with a coronagraph sited at an observatory dedicated to remote robotic observing (the Winer Observatory in Sonoita Arizona) that can obtain the quality and quantity of lunar sodium observations needed to answer these questions, and at modest cost. The design uses Commercial Off the Shelf Technology (COTS). We are working to begin routine the observations before the launch of the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission.
Morgan, Thomas↗
The historical contribution of solid rocket motors to the one centimeter debris population
The measured small particle population in earth orbit contains cm-sized objects that are not accounted for by breakup fragments. It was proposed that slag ejection during solid rocket motor burn is a contributor to this population. The direct evidence for such slag ejection follows from: observations of the exhausts of vehicles in flight, and engineering data from static firings. A source model is presented to account for the contribution of slag expulsion from solid rocket motors to the debris population. The mass and velocity distribution of the slag effluents are taken into account and used as a source term in the debris environment model. The model is based on the available observation data and on models for slag development and ejection.
Jackson, Albert↗
Orbital debris: Technical issues and future directions
An international conference on orbital debris sponsored jointly by the American Institute of Aeronautics and Astronautics, NASA, and the Department of Defense, was held in Baltimore, Maryland, 16-19 Apr. 1990. Thirty-three papers were presented. The papers were grouped into the areas of measurements, modeling, and implications of orbital debris for space flight. New radar and optical measurements of orbital debris were presented that showed the existence of a large population of small debris. Modeling of potential future environments showed that runaway growth of the debris population from random collisions was a real possibility. New techniques for shielding against orbital debris and methods for removal of satellites from orbit were discussed.
Potter, Andrew↗
Observational studies of the exospheres of the Moon and Mercury
The sodium and potassium atmospheres of Mercury and the Moon are mapped using spectroscopic measurements of resonance scattered sunlight. The objective is to define the sources and sinks for these atmospheric constituents, and in doing so, provide a better understanding of atmospheric processes on these bodies. These bodies are unique in that their atmospheres consist solely of an exosphere with the planetary surface at its base.
Potter, Andrew↗
Micrometeoroids and debris
The materials with vulnerability to micrometeoroids and space debris are discussed. It is concluded that all materials are vulnerable to hypervelocity impacts and that the importance of these impacts depends on the function of material. It is also concluded that low earth orbits are the most significant region relative to orbital debris. The consequences of aerospace environment effects are discussed.
Potter, Andrew↗
Working group written presentation: Meteoroid/orbital debris effects on materials
Low earth orbit (LEO) is the most significant region relative to orbital debris, since the flux of orbital debris peaks in the region from 800 to 1000 kilometers, and the relative velocities of objects in LEO are about 10 kilometers per second. The flux and relative velocities of objects in geosynchronous orbit (GEO) are small, so that debris is not considered to be a problem in GEO. The meteoroid environment is independent of orbit or altitude, so that its effects are the same in LEO and GEO. The effects of orbital debris and meteoroid impacts can be divided into two broad regions: (1) Erosion and pitting; Small particles (less than 100 microns) are very numerous. Impacts from these generally do not lead to penetration of surfaces, but cause pitting and erosion. The Solar Max surfaces were peppered with thousands of tiny impact pits. (2) Catastrophic impacts; Large debris particles are few in number relative to small debris, so that the probability of an impact is low. However, the effects of an impact of a large particle at 10 kilometers per second are devastating. These effects are examined.
Potter, Andrew↗
Interfacing the expert: Characteristics and requirements for the user interface in expert systems
Because expert systems deal with new sets of problems presenting unique interface requirements, special issues requiring special attention are presented to user interface designers. External knowledge representation (how knowdedge is represented across the user interface), modes of user-system interdependence (advisory, cooperative, and autonomous), and management of uncertainty (deciding what actions to take or recommend based on incomplete evidence) are discussed.
Potter, Andrew↗