Plus a “Goodbye” to Ulysses
Greenbelt MD, USA — EIT (Extreme ultraviolet Imaging Telescope) images the solar atmosphere at several wavelengths, and therefore, shows solar material at different temperatures. (Source: http://umbra.nascom.nasa.gov/eit/)

In the images taken at 304 Angstroms (example shown here) the bright material is at 60,000 to 80,000 Kelvin. (Image courtesy NASA)

In other images such as those those taken at 171 Angstroms, at 1 million Kelvin. 195 Angstrom images correspond to about 1.5 million Kelvin, 284 Angstrom to 2 million degrees.

The hotter the temperature, the higher you look in the solar atmosphere.

Visit SOHO Explore! to learn more about the Sun. (http://sohowww.nascom.nasa.gov/explore/)

About the SOHO Mission

SOHO, the Solar & Heliospheric Observatory, is a project of international collaboration between ESA and NASA to study the Sun from its deep core to the outer corona and the solar wind.

SOHO was launched on December 2, 1995. The SOHO spacecraft was built in Europe by an industry team led by prime contractor Matra Marconi Space (now EADS Astrium) under overall management by ESA.

The twelve instruments on board SOHO were provided by European and American scientists.

Nine of the international instrument consortia are led by European Principal Investigators (PI’s), three by PI’s from the US. Large engineering teams and more than 200 co-investigators from many institutions supported the PI’s in the development of the instruments and in the preparation of their operations and data analysis.

NASA was responsible for the launch and is now responsible for mission operations. Large radio dishes around the world which form NASA’s Deep Space Network are used for data downlink and commanding. Mission control is based at Goddard Space Flight Center in Maryland.

Further information about SOHO: * SOHO Fact Sheet (PDF) (http://soho.esac.esa.int/about/docs/SOHO_Fact_Sheet.pdf)

NOTE: Upon receipt of the last command from Earth, the transmitter on Ulysses switched off on June 30, 2009, bringing one of the most successful and longest missions in spaceflight and solar study history to an end.

After 18.6 years in space and defying several earlier expectations of its demise, the joint ESA/NASA solar orbiter Ulysses achieved ‘end of mission’. The craft is nearly out of hydrazine fuel for its stabilizing thrusters, and there’s not enough money to continue the mission for another year.

A final communication pass with a ground station enabled the final command to be issued to switch the satellite’s radio communications into ‘monitor only’ mode. No further contact with Ulysses is planned.

Ulysses is the first spacecraft to survey the environment in space over the poles of the Sun in the four dimensions of space and time.

Among many other ground-breaking results, the hugely successful mission showed that the Sun’s magnetic field is carried into the solar system in a more complicated manner than previously believed. Particles expelled by the Sun from low latitudes can climb up to high latitudes and vice versa, even unexpectedly finding their way down to planets.

Regions of the Sun not previously considered as possible sources of hazardous particles for astronauts and satellites must now be carefully monitored.

“Ulysses has taught us far more than we ever expected about the Sun and the way it interacts with the space surrounding it,” said Richard Marsden, ESA’s Ulysses Project Scientist and Mission Manager.

So farewell, and congratulations on a job exceedingly well done.