urn:esa:psa:context:instrument:uly.gas 1.0 1.11.0.0 Product_Context urn:nasa:pds:context:instrument:gas.uly 2021-02-24 1.0 Changed inst LIDs from u:n:p:c:i:instID.scID to u:n:p:c:i:scID.instID Changed LIDs from urn:nasa:pds: to urn:esa:psa: And per "Guide toPDS4 Context Products" v1.7, changed all lidvid_reference to lid_reference urn:esa:psa:context:instrument_host:spacecraft.uly instrument_to_instrument_host Witte, M., H. Rosenbauer, E. Keppler, H. Fahr, P. Hemmerich, H. Lauche, A. Loidl, and R. Zwick. The Interstellar Neutral-Gas Experiment On Ulysses, Astron. Astrophys. Suppl. Ser., 333, 1992. reference.WITTEETAL1992 Witte, M., H. Rosenbauer, M. Banaszkiewics, and H. Fahr, The Ulysses Neutral Gas Experiment: determination of the velocity and temperature of the interstellar neutral Helium, Adv. Space Res., 13, (6)121, 1993. reference.WITTEETAL1993 GAS INSTRUMENT Particle Detector not applicable not applicable Instrument Overview =================== (excerpted from [WITTEETAL1992]) Abstract. -- The properties (density, bulk velocity relative to the solar system, and temperature) of the local interstellar gas, represented by neutral helium penetrating the heliosphere, will be measured in-situ for the first time by the ULYSSES GAS instrument. By employing the solar gravitational field as a natural velocity analyser, the bulk velocity relative to the solar system and the temperature of the E as can be derived from the angular distributions of the particles measured in at least two widely separated points in the heliosphere. The gas density can be determined if a composition corresponding to cosmic abundances is assumed. The neutral particles are detected via the secondary electrons or ions which are emitted upon particle impact from a freshly deposited lithium-fluoride (LiF) layer. The physical principles and assumptions on which the experiment is based, the main technical features of the instrument, and first measurements in space are briefly described.