Results for “ErU” | Engineering Papers

DOE OSTI2020

Materials Data on ErU by Materials Project

UEr is Magnesium-derived structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. U is bonded to six equivalent U and six equivalent Er atoms to form UEr6U6 cuboctahedra that share corners with eighteen equivalent UEr6U6 cuboctahedra, edges with six equivalent UEr6U6 cuboctahedra, edges with twelve equivalent ErEr6U6 cuboctahedra, faces with eight equivalent UEr6U6 cuboctahedra, and faces with twelve equivalent ErEr6U6 cuboctahedra. All U–U bond lengths are 3.20 Å. All U–Er bond lengths are 3.41 Å. Er is bonded to six equivalent U and six equivalent Er atoms to form ErEr6U6 cuboctahedra that share corners with eighteen equivalent ErEr6U6 cuboctahedra, edges with six equivalent ErEr6U6 cuboctahedra, edges with twelve equivalent UEr6U6 cuboctahedra, faces with eight equivalent ErEr6U6 cuboctahedra, and faces with twelve equivalent UEr6U6 cuboctahedra. All Er–Er bond lengths are 3.20 Å.

36 MATERIALS SCIENCE↗

NASA NTRS1990

Project LOCOST: Laser or Chemical Hybrid Orbital Space Transport

A potential mission in the late 1990s is the servicing of spacecraft assets located in GEO. The Geosynchronous Operations Support Center (GeoShack) will be supported by a space transfer vehicle based at the Space Station (SS). The vehicle will transport cargo between the SS and the GeoShack. A proposed unmanned, laser or chemical hybrid orbital space transfer vehicle (LOCOST) can be used to efficiently transfer cargo between the two orbits. A preliminary design shows that an unmanned, laser/chemical hybrid vehicle results in the fuel savings needed while still providing fast trip times. The LOCOST vehicle receives a 12 MW laser beam from one Earth orbiting, solar pumped, iodide Laser Power Station (LPS). Two Energy Relay Units (ERU) provide laser beam support during periods of line-of-sight blockage by the Earth. The baseline mission specifies a 13 day round trip transfer time. The ship's configuration consist of an optical train, one hydrogen laser engine, two chemical engines, a 18 m by 29 m box truss, a mission-flexible payload module, and propellant tanks. Overall vehicle dry mass is 8,000 kg. Outbound cargo mass is 20,000 kg, and inbound cargo mass is 6,000 kg. The baseline mission needs 93,000 kg of propellants to complete the scenario. Fully fueled, outbound mission mass is 121,000 kg. A regeneratively cooled, single plasma, laser engine design producing a maximum of 768 N of thrust is utilized along with two traditional chemical engines. The payload module is designed to hold 40,000 kg of cargo, though the baseline mission specifies less. A proposed design of a laser/chemical hybrid vehicle provides a trip time and propellant efficient means to transport cargo from the SS to a GeoShack. Its unique, hybrid propulsion system provides safety through redundancy, allows baseline missions to be efficiently executed, while still allowing for the possibility of larger cargo transfers.

Dixon, Alan↗