Solar, a spaceborne observatory that had continuously monitored solar activity for the past nine years was switched off by the European Space Agency (ESA) on February 15, 2017. The last operation of this observatory was carried out by the French astronaut Thomas Pesquet. It was launched in February 2008 on the Space Shuttle Atlantis and was installed in the External Payload Facility of the Columbus laboratory, attached to the International Space Station.

In addition to helping us better understand the physics governing stars such as our Sun, Solar increases our knowledge of the solar energy that irradiates the Earth’s atmosphere. Understanding this energy and its fluctuations is a key to atmospheric modeling, atmospheric chemistry and climatology.

Solar is a suite of instruments mounted in a frame that rotates around two axes – the Coarse Pointing Device – to keep it pointing towards the Sun as the Space Station orbits the Earth. Its three instruments analyzed the complete spectrum of solar radiation, from extreme ultra-violet to infrared: SOVIM (Solar Variable and Irradiance Monitor), SOLSPEC (SOLar SPECtral Irradiance measurements) and SolACES (SOLar Auto-Calibrating Extreme UV/UV Spectrophotometers). Our Turin plant designed, built and integrated Solar, then Cannes carried out certain tests.

Solar’s prime objective was to measure the solar spectrum with unprecedented accuracy to calculate the “solar constant” and its variations very accurately – an extremely important parameter when assessing the total input of energy into the Earth-Atmosphere System for studies of atmospheric dynamics and Earth’s energy cycle. Scientists never expected Solar to collect data for nearly an entire solar cycle, but the suite has far exceeded everyone’s expectations. Solar’s results are an outstanding legacy for the scientific community. And our own teams have supported operations over these years, allowing them to broaden their scope of expertise.

Thales Alenia Space has been involved in ISS development since the outset. It has built several Space Station modules, and also contributed to operations, via logistics and engineering support, mission integration, etc. Astronauts have lived in our modules and used our facilities for months at a time, for example taking pictures from the Cupola we built, like Thomas Pesquet does these days, or Paolo Nespoli in the past… and other astronauts will in the near future!

Photos copyrights: © ESA/NASA