The ESA IUE Observatory

The ESA IUE Observatory was established in 1977 at the Villafranca Satellite Tracking Station, Madrid, Spain (VILSPA) in fulfillment of the requirements of the Memorandum of Understanding (M.O.U.) establishing the operations of the International Ultraviolet Explorer (IUE) satellite, between the IUE Project Partners NASA (National Aeronautics and Space Administration), the European Space Agency (ESA) and the British Science and Engineering Research Council (SERC). The ESA IUE Observatory was established solely to maintain and support the scientific operations of IUE for the European Astronomers, who visit this Observatory as Guest Observers.

Now its role, both in the International Astronomical Community as well as within Spanish Astrophysics and Space Sciences in general, has grown far beyond the scope foreseen. Also the impact of the IUE mission surpassed the original expectations and the innovative activities in th project, but especially the ESA IUE Observatory, which is not associated with any major scientific institute or scientific center, has established a world wide recognition in its 15 years of existence. This is the motivation for its presentation for the Premio "Principe de Asturias".

THE IUE MISSION

On the 26th of January 1978 the International Ultraviolet Explorer (IUE) was launched by a Thor-Delta rocket from Cape Canaveral and transferred to a geosynchronous orbit over the Atlantic Ocean. Even though the Satellite Tracking Station at Villafranca del Castillo, Madrid, Spain, was officially inaugurated by their Majesties the King and Queen of Spain on May 12, 1978 the ESA IUE Observatory was already opened to guest observers of the European scientific community on April 3, 1978. In the fifteen years of operations this small extraordinarily successful instrument has collected more than 90,000 ultraviolet spectra of all classes of astronomical objects.

HISTORICAL BACKGROUND.

The IUE project dates originally back to 1968, when it was still known as SAS-D (Small Astronomical Satellite). After various iterations it took its final form in 1974 when the three Agencies, NASA for the United States, ESA for Europe and SERC for the United Kingdom, signed the M.O.U. defining the IUE Project as an orbiting telescope with 45 cm aperture for spectroscopy in the ultraviolet wavelength domain between 115 nm and 320 nm. NASA agreed to build the telescope, the spectrographs, and the spacecraft, as well as to provide one Observatory. SERC provided the four spectrograph detectors, together with the necessary software. ESA built the solar panels and supplied the second Observatory at VILSPA, the ESA IUE Observatory. Since then, more than 1000 European programmes have been carried out at VILSPA on the Solar System, Stars and Interstellar Medium, Galaxies and Active Galactic Nuclei. More than 23,000 spectra from more than 10,000 celestial objects have been collected, processed for direct interpretation, and deposited in a public domain archive together with the data collected by NASA. The ESA IUE Observatory has been responsible for the management, maintenance and support for the access to this archive outside the US and UK. Access to the archival data, under the responsibility of the ESA IUE Observatory, amounts to more than 50% of the total usage of the data at a rate of 3 spectra per hour.

THE IUE SPACECRAFT.

The scientific instrumentation of the satellite consists of a Ritchey- Chretien Cassegrain telescope (0.45m; f/15), a Fine-Error-Sensor, two spectrographs and their cameras.

The satellite points anywhere on the celestial sphere, except within 45 of the Sun, with a stability better than 1 arcsec. The attitude control system moves the satellite over wide angle slews at a rate of 4.5 per minute. The desired target star falls at manoeuvre termination within the 16 arcmin. field of view of the fine guidance system. The spacecraft contains the subsystems necessary to support operation of such a scientific instrument such as: Communications, Command and Data Handling, Stabilization, Control and Power Systems. The high precision of the spacecraft attitude control system has been maintained over the years, even with the current set of only two Gyroscopes (6 at Launch). This extended life has enhanced the possibilities for innovations, even though the project at launch was already a unique facility.

BASIC ACTIVITIES:

The ESA IUE Observatory has over the extended 15 year lifetime of the IUE Satellite, not only fulfilled its original task, but has actually been able to break new terrain in the functionality of such a Space-Observatory Control Center, highlighting the importance of such a scientifically driven institute with a strong international, even though restricted, mandate. In spite of its small scientific staff, the ESA IUE observatory has, together with the support staff, been able to establish a widely recognized center, which has been driving innovative approaches in the areas of:
  1. the operations of Spacecraft Observatories,
  2. the support and development of international collaborations
  3. astrophysical research in a variety of fields, and
  4. the utilization of Archival Astronomical data.

Especially in this field the ESA IUE Observatory has impacted far beyond the countries supporting IUE directly. The developments at the ESA IUE Observatory have made it possible for scientists from developing countries to participate also in front line science through the innovative Archival structure, which was at the same time cost effective and versatile. Also institutes with limited resources can have efficient access to IUE data, just as the scientists in the developed countries. This was done through the development of the IUE Uniform Low Dispersion Archive (ULDA) with its associated Support Software Package (USSP). This development has made, through the 21 National ULDA Host Institutes, prime space science data from IUE available to scientists from 34 countries. A continuously growing User Community of 800 Astronomers have been able and are continuing to use the facilities supplied. These data are not only of importance for current direct research but also allow planning of observations with other instruments and for future projects.

SUPPORT OF SPACE SCIENCES DEVELOPMENT IN OTHER COUNTRIES

Although the IUE Project due to its nature has already some international aspects, the stimulus from the ESA IUE Observatory with its broader international outlook, has supported many scientists from countries not participating in the IUE Project. It also supplied access to its direct observing facilities. This special international outlook can also be recognized through the participation of its staff in the activities associated with the efforts of the Outer Space Division of the United Nations where important contributions have been made in the generation of coordination and cooperation between the space scientists both in developing as well as developed countries.

STIMULATION IN THE CONTEXT OF THE IBERIAN SPACE SCIENCE

The role of the ESA IUE Observatory in the context of Iberian Astrophysics is clearly recognized through the number of master's and doctoral Thesis which have been supported by the Observatory at different Universities. A significant group of young Spanish astrophysicists have received an important part of their professional formation in the ESA IUE Observatory (9 Masters Theses and 7 Ph.D Theses have been obtained under the full or partial supervision of the Observatory staff while currently 4 more Ph.D's are in progress). The staff of the ESA IUE Observatory has participated in the teaching of many astrophysics curricula at Spanish Universities. The newly formed Spanish Space Research Laboratory (Laboratory for Space Astrophysics and Fundamental Physics, LAEFF) has been established in 1990 on the premises of the Villafranca Satellite Tracking Station to establish an even closer cooperation between the Spanish Space research community and the ESA IUE Observatory. The staff of the ESA IUE Observatory has played prominent roles in the organization both scientifically and administratively of 4 International Conferences in Astrophysics and 2 Workshops held in Spain. Also 6 International Conferences and 1 Workshop in different countries.

STIMULATION OF COLLABORATION BETWEEN SCIENTISTS AND OBSERVATORIES ON A WORLDWIDE BASIS

The prominent scientific position of the ESA IUE Observatory has made it possible to stimulate, organize, and lead some of the major international collaborative research efforts in observational Astrophysics such as
  1. the 2nd largest (after the International Halley Watch) multi-spacecraft observing effort under the ROSAT-IUE-All Sky Survey (RIASS), in which not only these two spacecraft but also the Japanese X- Ray satellite GINGA and many ground based observatories have collaborated,
  2. the AGN Watch, a consortium of astrophysicists joining efforts to tackle the intriguing problems associated with the possible existence of Black holes in the nuclei of galaxies has been formed (62 participating scientists) under the leadership and the initiative of the ESA IUE Observatory, and
  3. The World Astronomy Days, a major effort associated with the International Space Year to stimulate and facilitate coordination of observations in astrophysics on a scale never attempted before.
The stimulus for collaboration in a way where the scientists are supported in the use of many facilities at the same time, without having to address these on an individual basis presents a major innovation in the way astrophysical observations could be made in the future.

Also the Observatory staff contributes actively to the divulgation of astronomical knowledge through all media in the Ibero-American World.

SPECIAL PUBLICATIONS AND CONFERENCE PROCEEDINGS PRODEUCED UNDER THE RESPONSIBILITY OF THE ESA IUE OBSERVATORY:

PROCEEDINGS:

  1. Proceedings of Workshop: Ultraviolet Stellar Classification, (VILSPA, Madrid), 1981, ESA SP-182
  2. Proceeedings of an ESA Workshop (Remeis Observatory, Germany): Recent Results on Cataclysmic Variables. 1985, ESA SP-236.
  3. Proceedings of the 2nd European IUE Conference, (AIT, Tubingen) 1980 ESA SP- 157
  4. Proceedings of the 3rd European IUE Conference, (CSIC, Madrid) 1982 ESA SP-176
  5. Proceedings of the 4th European IUE Conference, (CNRS, Rome) 1984 ESA SP-218
  6. Proceedings of an International Symposium (UCL London): New Insights in Astrophysics, 1986, ESA SP-263.
  7. Proceedings Celebratory Symposium, (GSFC, Greenbelt) A Decade of UV Astronomy with the IUE Satellite, 1988, ESA SP-281.
  8. Proceedings of an International Conference (CNES,Toulouse),1990, Evolution in Astrophysics, ESA SP-310.
  9. Physics of Classical Novae, Proceedings of the IAU Coll. 122, (Madrid) 1989, Lecture Notes in Phys. vol. 369, eds. A. Cassatella and R. Viotti.

SPECIAL PUBLICATIONS:

  1. IUE Low Dispersion Spectra Reference Atlas, 1984,ESA SP-1052, A. Heck, D. Egret, M. Jaschek and C. Jaschek.
  2. An Atlas of Ultraviolet Spectra of Supernovae, 1982,ESA SP-1046, P. Benvenuti, L. Sanz Fernández de Córdoba, W. Wamsteker, F. Machetto, G.C. Palumbo and N. Panagia.
  3. IUE-ULDA Access Guide #1:Dwarf Novae and Nova-like Stars, 1989, ESA SP- 1114, C. la Dous.
  4. IUE ULDA Access Guide #2: Comets, 1990, ESA SP-1134, M. Festou.
  5. IUE ULDA Access Guide #3: Normal Galaxies, 1992, ESA SP-1152, G. Longo and M. Cappaccioli.
  6. IUE ULDA Access Guide #4: Active Galaxies, 1992, ESA SP-1153, T. Courvoisier and S. Salvati.
  7. Be Star Atlas of Far UV and Optical High Resolution Spectra, ESA SP-1147, V. Doazan, G. Sedmak, M. Barylak and L. Rusconi.

OTHER INFORMATION ABOUT THE IUE DATA

Number of Ph.D's obtained using IUE data in 19 countries (Not including USA): 129

IUE data retrieval supported under ESA IUE Observatory: >160000 (50% of total). Users in 34 countries.

Number of publications (world wide) in the refereed litterature based on IUE data: >2500

Number of Guest observers and visiting scientists at the ESA IUE Observatory: >1000

Conferences organized: Madrid (Novae: 1992); Madrid (IUE: 1983), Salamanca (ISO: 1982); Toledo (mm Astronomy: 1981); London (IUE: 1986); Washington (IUE: 1988); Toulouse (IUE: 1990); Tubingen (IUE: 1980); Rome (IUE: 1984).

Workshops organized: Madrid (UV Classification: 1981); Bamberg (Cataclysmic Variables: 1983); Segovia (AGN: 1986)

ULDA National Hosts: Spain, Italy, Germany (2), United Kingdom, Sweden, France, Belgium, the Netherlands, Switzerland, Canada, United States, Brazil, Chile, Taiwan, Peoples Republic of China, Japan, Turkey, Israel, Former Soviet Union, Costa Rica