Gaia is a planned European Space Agency's (ESA) space observatory that will aim to chart a three-dimensional map of our Galaxy, the Milky Way. It is planned to operate around the Sun–Earth $L_2$ (SEL2) Lagrangian point. What is the flight plan to get Gaia in orbit around SEL2? We can break this down into a few sub-questions:

  • How many Earth flybys are planned?
  • Will the Moon be used as gravity assist?
  • Does it need lots of fuel to slow down near L2?

2 Answers 2


Spaceflight Now has a detailed overview of Gaia's launch sequence. There don't seem to be any Earth flybys or gravity assists planned. Just a single orbit around Earth after launch, then the burn to inject Gaia into its L2 transfer trajectory.
Gaia launch sequence When it arrives at L2, a delta-V of 180 meters per second inserts Gaia into its orbit around L2.
Note that seems to disagree with ESA's Gaia website, which states that Gaia will spend 4 days in Earth orbit for systems checks before the L2 injection burn.


Arianespace’s sixth Soyuz launch from the Guiana Space Center will carry the Gaia space telescope into orbit on L2 next 19th of December at 09:12:18 UTC. More detail about the launch sequence can be read from ESA site


and arianespace launch kit:


Day - 4



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