1992: Instrument (part of the EURECA mission) able to measure ozone, NO2, aerosols and water vapor in the near infrared, visible and near UV.
The Occultation Radiometer (ORA) instrument (part of the science panel of ESA’s European Retrievable CArrier (EURECA) mission) is a radiometer capable of measuring ozone, NO2, aerosols and water vapor by means of the occultation technique in the near infrared, visible and near UV. The mission was launched in 1992. It operated until 1993.
The Engineering service was responsible for the mechanical structure and the UV-visible unit. Also the electronics unit and the associated software were developed in-house.
Delivery year: 1992
ORA flight instrument
EURECA stands for EUropean REtrievable CArrier and was the name of a 4.5 tons heavy ESA spacecraft. On July 1st 1993 the EURECA satellite returned to Earth after a stay of 11 months in space. It was recovered from space by a Canadian robotic arm and placed in the cargo bay of the American Space Shuttle Endeavour. EURECA was built by the German company MBB-ERNO and onboard this satellite there were several European scientific instruments, a few of which were developed in Belgium.
EURECA spacecraft placed in space and retrieved by a Canadian robot arm onboard the Space Shuttle
After its launch on July 31st 1992 from the Kennedy Space Center in Florida, US, the American Space Shuttle Atlantis released the EURECA satellite into space on August 2nd 1992. It was placed in a circular orbit around the Earth with an inclination of 28.45° and at an altitude of 508 kilometers. Five days after its release it started its scientific observations. The satellite carried a number of microgravity experiments, some instruments for observation of the Earth’s atmosphere and the Sun and also a few instruments for material research. In total there were 15 active scientific instruments onboard and a few passive payloads. In total 71 scientific experiments were carried out during EURECA’s stay in space.
EURECA spacecraft placed in space and retrieved by a Canadian robot arm onboard the Space Shuttle
To foresee all this equipment with power EURECA was equipped with two solar panels, each with a surface of nearly 100 square meters and a maximum power of 1.500 Watts.
The original goal was to bring EURECA five times into space, with each time a different scientific payload. But after the first flight the satellite was never launched again. Today EURECA can be admired in the Swiss Transport Museum in Luzern.
ORA Filter Module
BIRA-IASB was involved in two instruments, one for the observation of the Sun and one for atmospheric research. This last instrument was called ORA. It was developed in collaboration with the Department of Atmospheric, Oceanographic and Planetary Physics of the University of Oxford. ORA, which stands for Occultation RAdiometer, is an instrument that could measure small amounts of gases and aerosols in the atmosphere of the Earth. For that purpose, a measurement was done during three minutes of the solar light that travelled through the atmosphere just before sun set or just after sun rise. This method is called the solar occultation technique. During these moments of sunrise and sunset, the solar light carries along spectral information about the chemical constitution of the atmosphere at different heights.
ORA flight model after return from space (BIRA-IASB museum)
EURECA turned around the Earth 16 times per day. In each revolution, ORA had the opportunity to measure a sunset and a sunrise. Like that a total of more than 7000 observations were performed. By coincidence, ORA was in space on the right time to see the huge injection of aerosols in the Earth’s atmosphere due to the eruption of the Pinatubo volcano in June 1991.
Publications
- Fussen, D.; Arijs, E.; Nevejans, D. (1995), “Nine months of atmospheric observation from the orbiting EURECA platform”, Nouvelles de la Science et des Technologies, Vol. 13, Issue 2-4, 155-160
- Arijs, E.; Nevejans, D.; Fussen, D.; Frederick, P.; Van Ransbeeck, E.; Taylor, F.W.; Calcutt, S.B.; Werrett, S.T.; Hepplewhite, C.L.; Pritchard, T.M.; Burchell, I.; Rodgers, C.D. (1995), “The ORA occultation radiometer on EURECA. Instrument description and preliminary results”, Advances in Space Research, Vol. 16, Issue 8, 33-36, DOI: 10.1016/0273-1177(95)00264-F
- Arijs, E.; Nevejans, D.; Fussen, D.; Frederick, P.; Van Ransbeeck, E.; Kotsira, C. (1994), “The ORA radiometer on EURECA: measurements of atmospheric minor constituents with a satellite borne radiometer”, (Vanderborght, O., Ed.), IGBP and 'Global Change' related research in Belgium II, 90-91
- Arijs, E.; Nevejans, D.; Fussen, D.; Frederick, P.; Van Ransbeeck, E. (1994), “ORA occultation radiometer on EURECA instrument description and preliminary results”, Space Scientific Research In Belgium, Vol. II Space Sciences, Issue Part 2, 61-78
- Fussen, D.; Arijs, E.; Nevejans, D.; Vanhellemont, F.; Brogniez, C.; Lenoble, J. (1998), “Validation of the ORA spatial inversion algorithm with respect to the Stratospheric Aerosol and Gas Experiment II data”, Applied Optics, Vol. 37, Issue 15, 3121-3127, DOI: 10.1364/AO.37.003121
- Nevejans, D.; Arijs, E.; Fussen, D. (1990), “The electronic and software design of the ORA occultation radiometer”, Proceedings of the IVth International Seminar: Manufacturing of Scientific Space Instrumentation, USSR, Frunze, September 18-24, 1989, Vol. 2, 61-73
