urn:nasa:pds:context:instrument_host:spacecraft.soho 1.0 1.7.0.0 Product_Context 2016-10-01 1.0 extracted metadata from PDS3 catalog and modified to comply with PDS4 Information Model urn:nasa:pds:context:investigation:mission.solar_and_heliospheric_observatory::1.0 instrument_host_to_investigation urn:nasa:pds:context:instrument:lasco.soho::1.0 instrument_host_to_instrument urn:nasa:pds:context:target:sun.sun::1.0 instrument_host_to_target Fleck B., V. Domingo, A.I. Poland, The SOHO Mission, Solar Phys., 162, 1-531, 1995. reference.FLECKETAL1995 SOLAR AND HELIOSPHERIC OBSERVATORY Spacecraft SOHO Instrument Host Overview ======================== The SOHO spacecraft was launched in December 1995, however the LASCO instrument did not begin regular observing until January 21, 1996. It has operated nearly continuously since then except for an interruption from June 25, 1998 until October 22, 1998. Smaller unplanned interruptions have occurred periodically, and pre-planned interruptions for routine maintenance, calibration, and satellite control have occurred, and will continue to occur until the conclusion of the mission. The SOHO spacecraft is three-axis stabilized and pointed towards the Sun with an accuracy of +/- 10 arcsec per 15 min. It consists of a Payload Module to accommodate the instruments and a Service Module carrying the spacecraft subsystems and solar arrays. SOHO occupies a halo orbit at the Earth-Sun L1 Lagrangian point to obtain uninterrupted sunlight. The design life was two years, but on-board consumables were sufficient for at least an extra four years of operations, and the nominal mission end is now March 2007. Twelve instruments comprise the payload, producing a continuous stream of data at 40 kbs, except when the solar oscillations imager Michelson Doppler Imager (MDI) operates in high-bit-rate mode, producing 160 kbs. The high-bit-rate mode is used during scheduled daily eight-hour periods or during dedicated campaigns. Magnetic tape stores data between telemetry contacts with the Experiment Operations Facility, located at NASA-GSFC. For more information, see B. Fleck, V. Domingo, and A. I. Poland, eds., Solar Physics, V. 162, 1995 [FLECKETAL1995]. Author ------- The text in this file was compiled by Matthew Knight, University of Maryland from online resources made publicly available by the SOHO website.