Author Archives: Guest Blogger

Gaia lift-off time

Launching a satellite seems fairly simple: put it onto a rocket and launch it into space. Of course it’s a bit more complicated than this and some missions are more complex than others. In the case of Gaia we have to launch at a very specific time each day. This lift-off time is determined by the Libration Point Mission Analysis Group of ESOC. In this blog entry I’ll explain why this launch time is so constrained and how we determine the exact lift-off time. There are three major factors that contribute to this launch: – The destination of Gaia, the Sun-Earth libration point, or Lagrange point 2 – The programming of the...

Gaia goes to L2 – what’s an “ell-two&...

Just like observatories on Earth, space observatories like Gaia like it quiet and dark. In space “quiet and dark” means far away from Earth. At large distances from Earth, the motion of spacecraft are no longer controlled only by the gravity of Earth, but also by other gravitational sources – most prominently by the Sun. The orbital motion of Earth around the Sun also influences the motion of spacecraft. The good thing about these forces – if you are a spacecraft – is that in five locations, all these forces balance out to create a stable location from which to study the wider Universe. These points are called the “Lagrange points”, or...