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Odin celebrates 15 years in orbit

20 February 2016

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The Swedish-led Odin satellite, developed in collaboration with Canada, Finland and France, celebrated its 15 year anniversary on 20 February 2016. Since 2008 the satellite is also part of ESA's Third Party Mission fleet. Odin is currently in good shape and continues collecting important atmospheric data.

The Odin satellite was designed and launched when ozone related measurements were of special interest. After its launch in February 2001, Odin was in place to monitor a unique event when the ozone hole over the South Pole was split into two parts during a few days. The long operational life of Odin has enabled collection of long time-series of various atmospheric data, thus contributing to climate relevant research.

Odin was designed as an observatory, with a capability to point into different directions and to be tuned to detect various substances, thus offering a considerable flexibility to scientists. Odin carries two instruments, Swedish SMR and Canadian OSIRIS, and by combining these two, scientists have been able to study e.g. noctilucent clouds and to carry out simultaneous measurements of water vapour. Another interesting example is measurements of nitrogen oxide transport from the upper atmosphere, where aurora related processes take place, to lower altitudes, where nitrogen oxide can affect the ozone layer.

The design lifetime of Odin was two years. The fact that Odin is still in such a good shape after 15 years in orbit can be explained by several reasons. One aspect is the fact that there is no fuel on-board, and the satellite is powered by solar cells that show only very slight degradation. Odin has a sun-synchronous orbit, and solar activity has been rather low during the last solar cycle, thus the orbital altitude has not decayed as much as initially predicted. During the solar eclipse season, Odin is powered by two NiCd batteries. The batteries undergo careful conditioning process before every eclipse season. These batteries have now been charged and discharged around 23,000 times.

Another reason for the long life of Odin is the fact that its initial orbit altitude was 600 km, which is a rather calm place. Odin's solar panels are exposed to the Sun whereas the temperature of the satellite is close to normal room temperature. The on-board computer has not been rebooted since the launch of the satellite, thus leading to a good stability of all systems. The only redundant part that has been taken in to use is a spare reaction wheel.

Odin operations are the responsibility of the Swedish National Space Board. Since 2008, Odin is a Third Party Mission within ESA's Earhnet programme. ESA contributes to the funding of operations, which go beyond the expected lifetime of the satellite. Within the Earthnet programme, ESA makes available data from over 30 satellites to scientific users in Europe and worldwide.