Satellites could experience increased drag due to the cooling of the upper atmosphere following changes in the current solar cycle identified by a Nasa mission.

Nasa’s thermosphere-ionosphere-mesosphere energetics and dynamics (TIMED) mission has observed a dramatic cooling of the upper atmosphere in response to the declining phase of the current solar cycle.

The TIMED mission has been developed to explore the Earth’s atmosphere above 60km altitude. It was launched in December 2001.

At present, the end of solar cycle 23 has offered TIMED an opportunity to study the radiative cooling in the thermosphere under exceptionally quiescent conditions.