Ulysses (spacecraft)
Names | Odysseus |
---|---|
Mission type | Heliophysics |
Operator | NASA / ESA |
COSPAR ID | 1990-090B |
SATCAT no. | 20842 |
Website | NASA Page ESA Page |
Mission duration | 18 years, 8 months, 24 days[1] |
Spacecraft properties | |
Manufacturer | Astrium GmbH, Friedrichshafen (formerly Dornier Systems) |
Launch mass | 371 kg (818 lb)[2] |
Payload mass | 55 kg (121 lb) |
Dimensions | 3.2 m × 3.3 m × 2.1 m (10.5 ft × 10.8 ft × 6.9 ft) |
Power | 285 watts |
Start of mission | |
Launch date | 6 October 1990, 11:47:16 UTC[2] |
Rocket | Space Shuttle Discovery (STS-41) with Inertial Upper Stage and PAM-S |
Launch site | Kennedy Space Center, LC-39B |
Contractor | NASA |
End of mission | |
Disposal | Decommissioned |
Deactivated | 30 June 2009 |
Orbital parameters | |
Reference system | Heliocentric orbit |
Perihelion altitude | 1.35 AU |
Aphelion altitude | 5.40 AU |
Inclination | 79.11° |
Period | 2,264.26 days (6.2 years) |
Flyby of Jupiter (gravity assist) | |
Closest approach | 8 February 1992 |
Distance | 440,439 km (6.3 Jupiter radii) |
Ulysses mission patch |
Ulysses (
To study the Sun at all latitudes, the probe needed to change its
The
Spacecraft
The spacecraft was designed by ESA and built by
Ulysses was
The spacecraft used S-band for uplinked commands and downlinked telemetry, through dual redundant 5-watt transceivers. The spacecraft used
Dual tape recorders, each of approximately 45-megabit capacity, stored science data between the nominal eight-hour communications sessions during the prime and extended mission phases.
The spacecraft was designed to withstand both the heat of the inner Solar System and the cold at Jupiter's distance. Extensive blanketing and electric heaters protected the probe against the cold temperatures of the outer Solar System.
Multiple computer systems (CPUs/microprocessors/Data Processing Units) are used in several of the scientific instruments, including several radiation-hardened RCA CDP1802 microprocessors. Documented 1802 usage includes dual-redundant 1802s in the COSPIN, and at least one 1802 each in the GRB, HI-SCALE, SWICS, SWOOPS and URAP instruments, with other possible microprocessors incorporated elsewhere.[8]
Total mass at launch was 371 kg (818 lb), of which 33.5 kg was hydrazine propellant used for attitude control and orbit correction.
Instruments
The twelve different Instruments came from ESA and NASA. The first design was based on two probes, one by NASA and one by ESA, but the probe of NASA was defunded and in the end the instruments of the cancelled probe were mounted on Ulysses.[9]
- Radio/Plasma antennas: Two beryllium copper antennas were unreeled outwards from the body, perpendicular to the RTG and spin axis. Together this dipole spanned 72 meters (236.2 ft). A third antenna, of hollow beryllium copper, was deployed from the body, along the spin axis opposite the dish. It was a monopole antenna, 7.5 meters (24.6 ft) long. These measured radio waves generated by plasma releases, or the plasma itself as it passed over the spacecraft. This receiver ensemble was sensitive from DC to 1 MHz.[10]
- Experiment Boom: A third type of boom, shorter and much more rigid, extended from the last side of the spacecraft, opposite the RTG. This was a hollow carbon-fiber tube, of 50 mm (2 in.) diameter. It can be seen in the photo as the silver rod stowed alongside the body. It carried four types of instruments: a solid-state magnetic search coilantenna measured AC magnetic fields.
- Body-Mounted Instruments: Detectors for electrons, ions, neutral gas, dust, and cosmic rays were mounted on the spacecraft body around the quiet section.
- Lastly, the radio communications link could be used to search for Doppler shifts) and to probe the Sun's atmosphere through radio occultation. No gravitational waves were detected.
- Total instrument mass was 55 kg.
- Magnetometer (MAG): MAG measured the magnetic field in the heliosphere. Measurements of Jupiter's magnetic field were also performed. Two magnetometers performed Ulysses' magnetic field measurements, the Vector Helium Magnetometer and the Fluxgate Magnetometer.[12]
- Solar Wind Plasma Experiment (SWOOPS): detected the solar wind at all solar distances and latitudes and in three dimensions. It measured positive ions and electrons.[13]
- Solar Wind Ion Composition Instrument (SWICS): determined composition, temperature and speed of the atoms and ions that comprise the solar wind.[14][15]
- Unified Radio and Plasma Wave Instrument (URAP): picked up radio waves from the Sun and electromagnetic waves generated in the solar wind close to the spacecraft.
- Energetic Particle Instrument (EPAC) and GAS: EPAC investigated the energy, fluxes and distribution of energetic particles in the heliosphere. GAS studied the uncharged gases (helium) of interstellar origin.
- Low-Energy Ion and Electron Experiment (HI-SCALE): investigated the energy, fluxes and distribution of energetic particles in the heliosphere.
- Cosmic Ray and Solar Particle Instrument (COSPIN): investigated the energy, fluxes and distribution of energetic particles and galactic cosmic rays in the heliosphere.
- Solar X-ray and Cosmic Gamma-Ray Burst Instrument (GRB): studied cosmic gamma ray bursts and X-rays from solar flares.
- Dust Experiment (DUST): Direct measurements of interplanetary and interstellar dust grains to investigate their properties as functions of the distance from the Sun and solar latitude.
Mission
Planning
Until Ulysses, the Sun had only been observed from low solar latitudes. The Earth's orbit defines the ecliptic plane, which differs from the Sun's equatorial plane by only 7.25°. Even spacecraft directly orbiting the Sun do so in planes close to the ecliptic because a direct launch into a high-inclination solar orbit would require a prohibitively large launch vehicle.
Several spacecraft (Mariner 10, Pioneer 11, and Voyagers 1 and 2) had performed gravity assist maneuvers in the 1970s. Those maneuvers were to reach other planets also orbiting close to the ecliptic, so they were mostly in-plane changes. However, gravity assists are not limited to in-plane maneuvers; a suitable flyby of Jupiter could produce a significant plane change. An Out-Of-The-Ecliptic mission (OOE) was thereby proposed. See article Pioneer H.
Originally, two spacecraft were to be built by NASA and ESA, as the International Solar Polar Mission. One would be sent over Jupiter, then under the Sun. The other would fly under Jupiter, then over the Sun. This would provide simultaneous coverage. Due to cutbacks, the U.S. spacecraft was cancelled in 1981. One spacecraft was designed, and the project recast as Ulysses, due to the indirect and untried flight path. NASA would provide the Radioisotope Thermoelectric Generator (RTG) and launch services, ESA would build the spacecraft assigned to Astrium GmbH, Friedrichshafen, Germany (formerly Dornier Systems). The instruments would be split into teams from universities and research institutes in Europe and the United States. This process provided the 12 instruments on board.
The changes delayed launch from February 1983 to May 1986 when it was to be deployed by the
Launch
Ulysses was deployed into low Earth orbit from the Space Shuttle Discovery. From there, it was propelled on a trajectory to Jupiter by a combination of solid rocket motors.[17] This upper stage consisted of a two-stage Boeing IUS (Inertial Upper Stage), plus a McDonnell Douglas PAM-S (Payload Assist Module-Special). The IUS was inertially stabilised and actively guided during its burn. The PAM-S was unguided and it and Ulysses were spun up to 80 rpm for stability at the start of its burn. On burnout of the PAM-S, the motor and spacecraft stack was yo-yo de-spun (weights deployed at the end of cables) to below 8 rpm prior to separation of the spacecraft. On leaving Earth, the spacecraft became the fastest ever artificially-accelerated spacecraft, and held that title until the New Horizons probe was launched.
On its way to Jupiter, the spacecraft was in an elliptical non-Hohmann transfer orbit. At this time, Ulysses had a low orbital inclination to the ecliptic.
Jupiter swing-by
It arrived at Jupiter on 8 February 1992 for a
Polar regions of the Sun
Between 1994 and 1995 it explored both the southern and northern polar regions of the Sun, respectively.
Comet C/1996 B2 (Hyakutake)
On 1 May 1996, the spacecraft unexpectedly crossed the ion tail of Comet Hyakutake (C/1996 B2), revealing the tail to be at least 3.8 AU in length.[18][19]
Comet C/1999 T1 (McNaught–Hartley)
An encounter with a comet tail happened again in 2004
Second Jupiter encounter
Ulysses approached
Comet C/2006 P1 (McNaught)
In 2007, Ulysses passed through the tail of comet
Extended mission
ESA's Science Program Committee approved the fourth extension of the Ulysses mission to March 2004 [24] thereby allowing it to operate over the Sun's poles for the third time in 2007 and 2008. After it became clear that the power output from the spacecraft's RTG would be insufficient to operate science instruments and keep the attitude control fuel, hydrazine, from freezing, instrument power sharing was initiated. Up until then, the most important instruments had been kept online constantly, whilst others were deactivated. When the probe neared the Sun, its power-hungry heaters were turned off and all instruments were turned on.[25]
On 22 February 2008, 17 years and 4 months after the launch of the spacecraft, ESA and NASA announced that the mission operations for Ulysses would likely cease within a few months.[26][27] On 12 April 2008, NASA announced that the end date will be 1 July 2008.[28]
The spacecraft operated successfully for over four times its design life. A component within the last remaining working chain of X-band downlink subsystem failed on 15 January 2008. The other chain in the X-band subsystem had previously failed in 2003.[29]
Even before the downlink signal was lost due to distance, the
The previously announced mission end date of 1 July 2008, came and went but mission operations continued albeit in a reduced capacity. The availability of science data gathering was limited to only when Ulysses was in contact with a ground station due to the deteriorating S-band downlink margin no longer being able to support simultaneous real-time data and tape recorder playback.[30] When the spacecraft was out of contact with a ground station, the S-band transmitter was switched off and the power was diverted to the internal heaters to add to the warming of the hydrazine. On 30 June 2009, ground controllers sent commands to switch to the low gain antennas. This stopped communications with the spacecraft, in combination with previous commands to shut down its transmitter entirely.[4][31]
Results
During cruise phases, Ulysses provided unique data. As the only spacecraft out of the ecliptic with a
Additional discoveries:[32][33]
- Data provided by Ulysses led to the discovery that the Sun's magnetic field interacts with the Solar System in a more complex fashion than previously assumed.
- Data provided by Ulysses led to the discovery that dust coming into the Solar System from deep space was 30 times more abundant than previously expected.
- In 2007–2008 data provided by Ulysses led to the determination that the magnetic field emanating from the Sun's poles is much weaker than previously observed.
- That the solar wind has "grown progressively weaker during the mission and is currently at its weakest since the start of the Space Age".[31]
Fate
Ulysses will most likely continue in heliocentric orbit around the Sun indefinitely. However, there is a chance that in one of its re-encounters with Jupiter a close fly-by with one of the Jovian moons would be enough to alter its course and so the probe would enter a hyperbolic trajectory around the Sun and leave the Solar System.[34]
See also
- Advanced Composition Explorer – NASA satellite of the Explorer program
- List of heliophysics missions
- List of missions to the outer planets
- Parker Solar Probe – NASA robotic space probe of the outer corona of the Sun
- Solar and Heliospheric Observatory – European space observatory
- STEREO – Solar observation mission (2006–present)
- TRACE – NASA satellite of the Explorer program
- WIND – NASA probe to study solar wind, at L1 since 1995
- Solar Orbiter – European space-based solar observatory
References
- ^ "Ulysses". NASA's Solar System Exploration website. Retrieved 25 September 2023.
- ^ a b "Ulysses". NASA's Solar System Exploration website. Retrieved 2 December 2022.
- ^ "Welcome to the HIA Ulysses Project". Herzberg Institute of Astrophysics. Archived from the original on 17 August 2011.
The Herzberg Institute of Astrophysics (HIA) of the National Research Council of Canada provided instrumentation and test equipment for the COsmic ray and Solar Particle INvestigation (COSPIN) on the Ulysses spacecraft. The COSPIN instrument consists of five sensors which measure energetic nucleons and electrons over a wide range of energies. This was the first participation by Canada in a deep-space interplanetary mission.
- ^ a b "Ulysses: 12 extra months of valuable science". European Space Agency. 30 June 2009. Retrieved 1 July 2009.
- ^ The odyssey concludes ... Archived February 24, 2012, at the Wayback Machine
- ^ https://rps.nasa.gov/missions/13/ulysses/
- ISBN 0-7106-0860-8
- ^ Ulysses NASA Documentation Archive Archived March 17, 2013, at the Wayback Machine This article incorporates text from this source, which is in the public domain.
- ^ "Ulysses factsheet". esa.int. Retrieved 7 May 2021.
- ^ Unified Radio and Plasma Wave Investigation, JPL Archived January 17, 2009, at the Wayback Machine
- ^ The Gravity Wave Experiment, Astronomy and Astrophysics Archived December 19, 2008, at the Wayback Machine
- Bibcode:1992A&AS...92..221B.
- ^ Goldstein, Bruce. SWOOPS/Electron – User Notes Archived September 27, 2006, at the Wayback Machine, Jet Propulsion Laboratory
- PMID 7754380.
- S2CID 189797680.
- ^ A Deathblow to the Death Star: The Rise and Fall of NASA's Shuttle-Centaur, ArsTechnica, October 2015
- ^ ESA—Space Science—Sun to set on Ulysses solar mission on 1 July
- S2CID 4418311.
- ^ a b Ulysses Catches Another Comet by the Tail
- ISBN 9781402028311.
- ^ G. Gloeckler et al. Cometary Ions Trapped in a Coronal Mass Ejection
- ^ Ulysses - Science - Jupiter Distant Encounter Selected References Archived September 23, 2008, at the Wayback Machine This article incorporates text from this source, which is in the public domain.
- doi:10.1086/521019.
- ^ ESA Science & Technology: Ulysses Mission Extended
- ^ ESA Portal - Ulysses scores a hat-trick
- ^ "Ulysses mission coming to a natural end". European Space Agency. 22 February 2008. Retrieved 23 February 2008.
- ^ "International Solar Mission to End Following Stellar Performance". NASA. 22 February 2008. Retrieved 23 February 2008. This article incorporates text from this source, which is in the public domain.
- ^ "RIP: Ulysses solar probe coming to end soon - Yahoo! News". Archived from the original on 17 June 2008. Retrieved 15 January 2017.
- ^ "February 2003 Operations". European Space Agency. Archived from the original on 3 July 2009.
- ^ Ulysses Mission Ops—No more data playback Archived December 2, 2008, at the Wayback Machine
- ^ a b "Ulysses Spacecraft Ends Historic Mission of Discovery". Jet Propulsion Laboratory. 30 June 2009. Archived from the original on 16 July 2009. Retrieved 1 July 2009. This article incorporates text from this source, which is in the public domain.
- ^ "International Mission Studying Sun to Conclude". NASA Jet Propulsion Laboratory (JPL). 12 June 2008. Retrieved 1 August 2021.
- ^ "Missions: Ulysses". Retrieved 1 August 2021.
- ^ "Solar orbiter Ulysses ends mission after 18 years". Reuters. July 2009.
External links
- ESA Ulysses website
- ESA Ulysses mission operations website
- ESA Ulysses Home page
- NASA/JPL Ulysses website
- Ulysses Measuring Mission Profile by NASA's Solar System Exploration
- ESA/NASA/JPL: Ulysses subsystems and instrumentation in high detail
- Where is Ulysses' now!
- Max Planck Institute Ulysses website
- Interview with Ulysses Mission Operations Manager Nigel Angold on Planetary Radio Archived 20 February 2012 at the Wayback Machine
- Interactive 3D visualisation of Ulysses Jupiter gravity assist and polar orbit around the Sun