Webb and Gaia welcome Euclid to L2

In the month after its launch on 1 July, Euclid has travelled 1.5 million kilometres from Earth towards the Sun-Earth Lagrange point L2, meaning it has ‘arrived’ at its destination orbit.

This animation showcases the orbits of Euclid (green), the James Webb Space Telescope (blue), and the Gaia mission (yellow) around this unique position in space. The positions of the spacecraft in this animation don’t correspond to their current positions in space.

Located about 1.5 million kilometres from Earth in the opposite direction from the Sun, L2 is about four times further away than our Moon. Several other space missions like Webb and Gaia also orbit L2 as it offers the perfect vantage point to study the Universe.

At L2, the spacecraft can keep the Sun, Earth and Moon behind them at all times, so they don’t interfere with observations, while at the same time getting a clear view of deep space and pointing an antenna back to Earth to remain in close communication.

Euclid and Webb’s halo orbit around L2 is big. In terms of distance, the ‘radius’ of Euclid’s orbit varies from about 400 000 kilometres at its closest to the centre, and up to 800 000 kilometres at its furthest. By the time Euclid has completed one full revolution around L2, the Moon will have circled the Earth six times. Gaia orbits L2 in a Lissajous orbit, with a maximum distance of around 350 000 km from its centre.

The region around L2 is big and even though the orbits of these spacecraft seem to cross in the animation, in reality there is plenty of space and a collision can be easily avoided. For example, Webb and Gaia are between 400 000 and 1 100 000 km apart, depending on where they are in their respective orbits.

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