INFO 23-1995: ESA innovation rescues Ultraviolet Observatory
16 October 1995The International Ultraviolet Explorer (IUE) spacecraft, launched in January 1978, is one of the longest living and most successful spacecraft ever launched. For 18 years the IUE spacecraft was operated jointly by ESA and NASA, where spacecraft control and science operations were distributed with 16 hours science operations from the NASA IUE observatory at GSFC in Maryland and 8 hours from the ESA IUE Observatory at VILSPA near Madrid, Spain.
Astrophysicist Freeman J. Dyson from the Institute for Advanced Studies in Princeton characterizes IUE as, "A little half-meter mirror sitting in the sky, unnoticed by the public, pouring out results."
By use of the IUE satellite, astronomers obtain access to the ultraviolet radiation of celestial bodies in unique ways not available by any other means, neither from the ground nor by any other spacecraft currently in orbit.
IUE serves a wide community of astronomers all over Europe, the United States and many other parts of the world. It allows the acquisition of critical data for fundamental studies of comets and their evaporation when they approach the Sun, of the mechanisms driving the stellar winds which make many stars lose a significant fraction of their mass (before they die slowly as White Dwarfs or in sudden Supernova explosions), as well as in the search to understand the ways in which black holes possibly power the violent nuclei of Active galaxies.
One year ago the project was threatened with termination and serious concern was expressed by astronomers about the potential loss of IUE's capabilities, as a result of NASA not continuing to operate the spacecraft. Under the leadership of ESA, the three Agencies involved in the operations of IUE (ESA, NASA and the United Kingdom's Particle Physics and Astronomy Research Council, PPARC), reviewed the operations agreements of the Project.
A minor investment allowing the implementation of modern management and engineering techniques as well as a complete revision of the communication infrastructure of the project and continuous improvements in efficiency in the ESA management, also taking advantage of today's technologies, both in computing and communications, have made it possible to continue IUE operations within the financial means available, with ESA taking up most of NASA's share in the operations. According to Dr. Willem Wamsteker, ESA's Dutch IUE Project Scientist, "it was a extremely interesting experience to have the opportunity to do an in-depth review of operational procedures established in 1978 and be given the chance to streamline these through the application of the tools available to engineers and scientists in 1995."
The innovative arrangements were designed and developed at the ESA IUE Observatory, which is located in Spain at ESA's Villafranca Satellite Tracking Station in Villanueva de la Canada near Madrid. As a result, ESA is now performing all of IUE's science observations (16 hours per day) from the Villafranca station. All the processing of the observations transmitted by the satellite and the subsequent rapid data distribution to the research scientists world-wide is now done from Villafranca. NASA does maintain its role in the programme in the area of operational spacecraft maintenance support, satellite communications and data re-processing for IUE's Final Archive.
Thus the IUE Project could be extended and the final IUE observing program can now be implemented. In particular, this will involve critical studies on comets (e,g. on Comet Hale-Bopp), on stellar wind structures, on the enigmatic mini-quasars (which are thought to power the nuclei of Active Galaxies), as well as performing pre- studies which will optimize the utilization of the Hubble Space Telescope.
Prof. R.M. Bonnet, Director of the ESA Science Programme comments: "I am quite pleased that we have been able to secure the extension of our support for the scientists in Europe and the world to this highly effective mission. Also the scientists can be proud of the utilization of IUE, with more than 3000 learned publications and 200 Doctoral dissertations based on data from IUE. Through this they demonstrate in turn to be very appreciative of our efforts in the Science Programme."