The European Space Agency's Aeolus mission, designed to study the world's winds, is on track for a 2016 take-off. Following a troubled development process, the two lasers central to the project are now complete, allowing the team to ramp up testing ahead of launch.
Part of ESA's Earth Explorers program, the Aeolus mission is designed to improve our understanding of the planet's atmosphere and weather systems, monitoring the weather in different part of the world to build complex models of the environment. The findings are expected to lead to improved weather forecasting.
In order to achieve that goal, the satellite needs to carry some advanced technology, much of which is being developed specifically for the project. At the heart of the satellite will be a custom wind lidar, known as Aladin, incorporating a telescope, two lasers (one active and one spare) and a number of sensitive receivers.
In order to study the winds that swirl around the Earth, the onboard laser will generate UV light, beaming it down towards the planet. As the light travels, it will bounce off molecules in the air – as well as particles of dust and ice, and water droplets in the atmosphere – with the frequency of the light being altered as it interacts with the tiny obstacles.
The small amount of light that is scattered back towards the orbiting satellite will then be collected by Aladin's telescope. Measuring the returned light and comparing it with the properties of the original laser will allow scientists to study the winds below.
The development of the two lasers that form part of Aladin was troubled. The team encountered numerous difficulties over more than a decade of work, with issues particularly focused on making sure the equipment functioned properly in a vacuum. Both lasers are now complete and ready to be integrated with the rest of the instrument at the Airbus Defence and Space facility in Toulouse, France.
Once Aladin is in its final form, testing will begin on the complete instrument, with the goal of being ready for insertion into orbit by the end of the year.