2,945 research outputs found
Functional requirements for onboard management of space shuttle consumables, volume 1
A study was conducted to determine the functional requirements for onboard management of space shuttle consumables. A generalized consumable management concept was developed for application to advanced spacecraft. The subsystems and related consumables selected for inclusion in the consumables management system are: (1) propulsion, (2) power generation, and (3) environmental and life support
Characterization of the Heavy Metal Pyrochlore Lattice Superconductor CaIr2
We report the electronic properties of the cubic laves phase superconductor
CaIr2 (Tc = 5.8 K), in which the Ir atoms have a Pyrochlore lattice. The
estimated superconducting parameters obtained from magnetization and specific
heat measurements indicate that CaIr2 is a weakly coupled BCS superconductor.
Electronic band structure calculations show that the Ir d-states are dominant
at the Fermi level, creating a complex Fermi surface that is impacted
substantially by spin orbit coupling.Comment: 6 pages, 4 figs and 1 table. arXiv admin note: text overlap with
arXiv:1406.295
Spacelab simulation using a Lear Jet aircraft: Mission no. 4 (ASSESS program)
The fourth ASSESS Spacelab simulation mission utilizing a Lear Jet aircraft featured trained experiment operators (EOs) in place of the participating scientists, to simulate the role and functions of payload specialists in Spacelab who may conduct experiments developed by other scientists. The experiment was a broadband infrared photometer coupled to a 30-cm, open port, IR telescope. No compromises in equipment design or target selection were made to simplify operator tasks; the science goals of the mission were selected to advance the mainline research program of the principle investigator (PI). Training of the EOs was the responsibility of the PI team and consisted of laboratory sessions, on-site training during experiment integration, and integrated mission training using the aircraft as a high-fidelity simulator. The EO permission experience in these several disciplines proved adequate for normal experiment operations, but marginal for the identification and remedy of equipment malfunctions. During the mission, the PI utilized a TV communication system to assist the EOs to overcome equipment difficulties; both science and operations were successfully implemented
Controlled Contact to a C60 Molecule
The conductance of C60 on Cu(100) is investigated with a low-temperature
scanning tunneling microscope. At the transition from tunneling to the contact
regime the conductance of C60 adsorbed with a pentagon-hexagon bond rises
rapidly to 0.25 conductance quanta G0. An abrupt conductance jump to G0 is
observed upon further decreasing the distance between the instrument's tip and
the surface. Ab-initio calculations within density functional theory and
non-equilibrium Green's function techniques explain the experimental data in
terms of the conductance of an essentially undeformed C60. From a detailed
analysis of the crossover from tunneling to contact we conclude that the
conductance in this region is strongly affected by structural fluctuations
which modulate the tip-molecule distance.Comment: 4 pages, 3 figure
NASA/ESACV-990 spacelab simulation. Appendix B: Experiment development and performance
Eight experiments flown on the CV-990 airborne laboratory during the NASA/ESA joint Spacelab simulation mission are described in terms of their physical arrangement in the aircraft, their scientific objectives, developmental considerations dictated by mission requirements, checkout, integration into the aircraft, and the inflight operation and performance of the experiments
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