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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Response to Comment on “Radiation-Belt Remediation Using Space-Based Antennas and Electron Beams” by G. Ganguli and C. Crabtree

Ganguli and Crabtree have written a comment about a recent article by the authors listed above on radiation-belt remediation. They have objected to our evaluation of the Naval Research Laboratory’s chemical release concept which states that this concept may be impractical due to an apparently low overall efficiency. In their comment, they provide a scientific argument and refer to the published literature to counter our statement. Here, in this response, we provide more details on our numerical calculations and experimental results which led to this evaluation.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

Low Size, Weight, and Power Space-Based Imaging System

The proposed low-SWAP solution is a FPA focus mechanism which is composed of an actuator motor, attached to a flexure that holds the camera sensor while imaging. The mechanism, while moderately complex, allows for large changes in the focal plane while also maintaining the ability to make small adjustments to produce the best possible data. This solution does the best job at accounting for thermal gradients within the optical components that tend to degrade the image quality.

42 ENGINEERING↗
DOE OSTI2023

The Vela Hotel Program: The AEC's Space-Based Nuclear Detection and Treaty Verification Program [Slides]

Early Interest in "Detection": "I would suggest that the best way to get reliable information in a short time would be to send from the States a man qualified to do the testing of the samples on the spot. This man should be officially a representative of the State Department, and his detecting devices, such as small portable Geiger Counters, could then go into Switzerland in the diplomatic pouch via air from Southern Italy. This man could then contact, through the Embassy, suitable people who could collect the water samples without arousing too much curiosity. A fishing trip in a boat would probably give the best disguise, as the fisherman could carry a water bottle in his lunch basket, and fill it after drinking the original contents. The water should be collected from the center of the river, to get the swiftest flowing water, so that the holdup could be minimized. In the lake, the water should be collected as near to the suspected site as possible, or as near to each of the inlet rivers as can be done. Speed in getting from the collection point to the counting room is of great importance, as you are, no doubt, aware." - Luis Alvarez to Major Furman, May 1944.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2023

Possible routes to a strong science case for a joint CLEoPATRA-Roman microlensing survey

The Contemporaneous LEnsing Parallax and Autonomous TRansient Array (CLEoPATRA) is a mis sion concept for a space-based microlensing survey, proposed to enhance science for the Roman Space Telescope (RST) microlensing survey. From CLEoPATRA’s planned vantage point in geosynchronous equatorial orbit (GEO), it will observe microlensing events simultaneously and from a different point of view to RST at L2. This joint L2-GEO observation baseline gives a projected angular separation of order the size of the characteristic angular lensing scale of Free-Floating-Planets (FFPs) in the Galaxy, making it powerful for constraining FFP properties. We find that a strong science case will demonstrate which parts of the FFP parameter space a joint RST-CLEoPATRA survey will give lead ing lens constraints compared with competing ground- and space- based RST observatory companions (e.g., PRIME, Euclid). Both the simulations and framework that connect telescope capabilities to physical constraints already exist for RST FFPs and can be used to demonstrate the power of joint RST-CLEoPATRA survey, with the addition of a simulated CLEoPATRA event blending distribution. Population-level FFP constraints could also be calculated by adapting ongoing black hole microlensing research at Lawrence Livermore National Laboratory. We also find that considering CLEoPATRA as a third space-based observatory (in addition to RST and Euclid/PRIME), which will break microlensing degeneracies leading to unambiguous FFP constraints, is worth investigating as part of a science case. Finally, we highlight possible auxiliary CLEoPATRA science cases including relieving tension between the RST Core Community Surveys.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2022

Constraining time dependent dark matter signals from the Sun

Dark matter (DM) particles captured by the Sun can produce high-energy electrons outside the Sun through annihilating into meta-stable mediators. The corresponding cosmic-ray electron signals observed by the space-based experiments will be time dependent due to the orbital motion of the space-based detectors. The shape of this time dependence is predictable given the orbital information of the detectors. Since the high-energy CR electron (with energy E > 100 GeV) fluxes are expected to be constant in time, non-observation of such time variation can be used to place upper limits on the DM annihilation cross section. Here we analyze the time dependence of dark matter cosmic-ray signals in three space-based experiments: AMS-02, DAMPE and CALET. Under the assumption that no time dependent signal is observed, we derive the 95% C.L. exclusion limits on the signal strength from the current data. We map our limits onto the parameter space of the dark photon model and find that the constraints are comparable with that derived from the supernova SN1987A.

79 ASTRONOMY AND ASTROPHYSICS↗