Tag Archives: l2

… and we got there!

ESA’s billion-star surveyor Gaia is now in its operational orbit around a gravitationally stable virtual point in space called ‘L2’, 1.5 million km from Earth. Via ESA web

The flight dynamics expertise behind Gaia’s criti...

Today is a big day for the flight dynamics experts who determine and predict trajectories, prepare orbit manoeuvres and determine satellite attitudes. At around 19:58 CET this evening, five of Gaia's eight thrusters will be commanded to fire an automated burn lasting almost two hours. It's a critical manoeuvre meant to bring Gaia onto its planned operational orbit about the L2 Lagrange point (a second, smaller, burn on 14 January will complete the process). The event may appear straightforward, but it marks the culmination of years of careful mission analysis work supported by orbital calculations. The ease of getting into the proper orbit – denoted by a mere two lines in the mission...

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...

Update on Planck’s Big Burn

Update from ESA's Steve Foley at ESOC, the Spacecraft Operations Manager for Planck. We started the large manoeuvre last night at 23:00 local and watched as the 20N thrusters started up and began to push Planck ever further from her parking position at SEL2. The manoeuvre will take nearly two days as we only fire for a few seconds every minute as we spin around the principle axis at 1 rpm. We checked early this morning on Estrack Malargüe and the burn was on-going, on schedule with all systems nominal. We had used around 20kg of fuel during the night and had achieved a little more than 20% of the required delta-V....

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...

The best spot for space astronomy

Editor's note: Today's post was contributed by Markus Landgraf from the Mission Analysis Section at ESA's ESOC establishment, Darmstadt, Germany. It highlights the detailed assessment of options, scientific and practical factors that must be taken into account before any mission can be flown. If we are to explore not only our solar system, but also the cosmos in more general, we have to rely on telescopes to collect starlight. For most applications this is most efficiently done outside the Earth’s atmosphere and thus follows the need for installation and operation of space telescopes. Globally speaking Europe leads astronomy research, not only due to our history, but also due to the missions currently...