Ulysses

Ulysses is a joint NASA / ESA mission designed to study the polar regions of the Sun. Originally named the International Solar Polar Mission, Ulysses' primary scientific objectives are to investigate, as a function of solar latitude, (1) the properties of the solar corona, (2) the solar wind, (3) the structure of the Sun-wind interaction, (4) the heliospheric magnetic field, (5) solar and non-solar cosmic rays, (6) solar radio bursts and plasma waves, (7) solar x-rays, and (8) interstellar / interplanetary neutral gas and dust. The spacecraft was placed onto a trajectory that intercepted Jupiter and used the gas-giant's gravity to leave the ecliptic plane. Ulysses' first pass above the Sun's southern pole was completed in November 1994, and its first pass above the northern pole was completed in Ulysses completed in October l995, ending the primary mission. The mission was subsequently extended to permit further observations.

Spacecraft
Spin stabilized at 5 rpm (Earth pointing). X-, S- band communications using 1.65 m HGA. RTG used for power generation, provides 285 W (BOL). Hydrazine propulsion for trajectory correction maneuvers. Redundant tape recorders store 46 Mb each. 3 deployable booms for science instruments.

Payload
Ulysses carries 9 instruments in addition to using the radio system for scientific investigations. Total payload mass is 55 kg. Magnetometer (VHM/FGM) - designed to measure changes in the interplanetary magnetic field at different heliographic latitudes, Solar Wind Plasma Experiment (SWOOPS) - studies protons, electrons and heavy ions in the solar wind and their dependence on distance from the Sun and heliospheric latitude, Solar Wind Ion Composition Instrument (SWICS) - studies the elemental and ionic-charge composition, and the mean temperatures and mean speeds of all solar-wind ions from hydrogen to iron, Unified Radio and Plasma Wave Instrument (URAP) - designed to determine the direction and polarization of distant radio sources, as well as radio bursts from charged particles in the solar wind, Energetic Particle Instrument (EPAC) - measures intensities and energies of interplanetary ions to resolve their masses and to observe helium penetrating the heliosphere from interstellar space, Heliosphere Instrument for Spectral, Composition and Anisotropy at Low Energies (HISCALE) - designed to measure elemental abundances of interplanetary ions and electrons, Cosmic Ray and Solar Particle Instrument (COSPIN) - will resolve outstanding problems in solar, interplanetary and cosmic-ray physics for which observations far out of the ecliptic plane are required, Solar X-Ray and Cosmic Gamma-Ray Burst Instrument (GRB) - measures electrons in solar flares and determines the direction of gamma-ray bursts from distant galaxies, Cosmic Dust Experiment (CDE) - will provide direct observations of particulate matter and its interaction with solar radiation as a function of ecliptic latitude. Additionally, the spacecraft's radio subsystem will be used to measure density, turbulence and velocity of the plasma in the Sun's corona, as well as search for the presence of passing gravity waves.

Country of Origin	International
Customer/User	ESA, NASA, JPL
Manufacturer(s)	Dornier Systems
Size	3 m x 3 m x 2 m
Orbit	Jupiter gravity assist and plane change (JGA) with Jupiter closest approach on February 8, 1992 : Heliocentric, 5 x 1.3 AU, polar
Design Life	5 years
Related Sites	JPL Ulysses Page Ulysses Mission Home Page ESA Ulysses Page

Launch Facts

Name	Int'l Desig.	Date	Site	Vehicle	Orbit	Mass(kg)
Notes
Ulysses	1990-090B	10/6/90	ESMC	STS 41	Solar	367
Deployed from STS 41 10/6/90; solar research