Max Planck Institute for Solar System Research | 2019 Oct 07
The balloon mission Sunrise is to take off again in two years. The telescope’s main mirror has now been coated with a fresh layer of aluminum.
The balloon mission Sunrise, which aims a high-resolution telescope at the Sun from a flight altitude of more than 35 kilometers, is preparing for its next flight. The observatory is scheduled to embark on its third expedition in the summer of 2021. Preparatory work on the main mirror measuring one meter in diameter has already begun. At the Calar Alto Observatory in southern Spain, the mirror has now been coated with a new layer of aluminum. Scientists and engineers from the Max Planck Institute for Solar System Research (MPS) in Germany, which leads the mission, accompanied the work on site.
The Sunrise mission is an adventure: carried by a giant helium balloon, the unmanned observatory peers at the Sun from an altitude of more than 35 kilometers; several days of flight are followed by a parachute landing. Twice already, the delicate main mirror of Sunrise’s telescope has survived this daring expedition undamaged. "But such a flight does not leave the mirror completely unscathed," explains Sunrise project manager Dr. Andreas Lagg from MPS. The quality of the outer layer of reflective aluminum is impaired; it must be renewed before every additional flight.
Telescopes that look into space from the ground face a similar problem: wind and weather affect their thin aluminum layer. The Calar Alto Observatory in the Sierra de los Filabres in southern Spain, which is operated by the Andalusian Institute for Astrophysics (IAA), a partner of the Sunrise mission, is therefore equipped with its own facility for re-aluminizing mirrors. There, the Sunrise mirror has now been spruced up for its next mission. ...