Over more than 18 years of observations above and below the poles of the Sun, the ESA/NASA Ulysses mission has made fundamental contributions to our understanding of the Sun itself, its sphere of influence (the heliosphere), and our local interstellar neighbourhood. The mission provided the first-ever map of the heliosphere in the four dimensions of space and time.
Ulysses was launched by Space Shuttle Discovery in October 1990. It headed out to Jupiter, arriving in February 1992 for the gravity-assist manoeuvre that swung the craft into its unique solar orbit. It orbited the Sun three times and performed six polar passes.
The mission will be shut down on 30 June 2009.
Credits: ESA (image by C.Carreau)
The orbit of Ulysses was chosen so as to chart the heliosphere – the sphere of influence of the Sun carved out by the solar wind that extends beyond the outer fringes of the Solar System - at all solar latitudes.
Ulysses’s orbit is an ellipse with the Sun at one focus (heliocentric), and is inclined 80° with respect to the Sun’s equator (polar). The orbital period is 6.2 years. Maximum distance from the Sun (aphelion) is reached at about 810 million km (or 5.4 AU; one AU or Astronomical Unit equals the average distance between Earth and the Sun, or about 150 million km) and minimum distance (perihelion) is at about 200 million km (or 1.3 AU).
Ulysses was launched on 6 October 1990. It then headed out to Jupiter, arriving on 8 February 1992 for the gravity-assist manoeuvre that swung the craft into its unique solar orbit.
Over more than 18 years of operation, Ulysses orbited the Sun three times and performed six polar passes, during which the spacecraft was above 70° heliospheric latitude in either hemisphere (South pole: June–November 1994, September 2000 – January 2001, November 2006 – April 2007. North pole: June–September 1995, August–December 2001, November 2007 – March 2008).
As of early 2009, Ulysses has travelled 8.6 thousand million km (or 57.65 AU) at an average speed of 56 000 km/hr.
Credits: ESA (animation by C.Carreau)