At the present international space symposium in Visby, Sweden, one of the topics is the Swedish satellite Odin, which is now on its seventh year of operations. Quite recently, scientists have discovered that Odin's measurements can be used also to study the presence of clouds and aerosols in the stratosphere. Clouds and aerosols may have a cooling effect on our planet, as against the warming effect of carbon dioxide.

Today, scientists do not have sufficient knowledge about the possible cooling effect of clouds. Measurements made in space could determine how much of the sunlight is reflected back into space by clouds. Odin has measured, and is still measuring, the amount of clouds, both visible and invisible to the human eye, and Odin data have indicated significant divergence from existing forecast models. This kind of information could help us improve our knowledge about the processes of global warming. We need more knowledge about our climate, and we need it soon, in order to improve exisiting models in this field.

Since 2001, Odin has continuously studied the chlorine chemistry in the ozone layer. Chlorine compounds break up the ozone and make the gaseous layer thinner. Observations made by Odin aim to evaluate exisiting theories about the ozone depletion. For these studies, it is important to do research during a long period of time.

Although the Odin satellite has exceeded its planned lifetime by five years, it is not immortal. It is therefore important that Odin gets a successor which can continue to provide us with information about our climate and our environment.

A small step in the right direction is the further development of a sofisticated instrument, a radiometer, which is used on Odin. This development work is performed by SSC within the frame of a study for the Swedish National Space Board, for use by the European Space Agency, ESA. The main objective of the instrument is to investigate the climate changes in the upper troposphere and the lower stratosphere.

About Odin

Odin was developed by SSC för the space agencies of Sweden, France, Canada and Finland. Since it was launched in 2001, Odin has had two missions; astronomy and aeronomy. The astronomy studies were completed in spring 2007, and Odin is now only used for atmosphere research. Odin was designed for two years' operations but after more than six years, it is still working well and providing valuable data.