Artist’s impression of Euclid.

Status
Implementation

Objective
To understand the nature of dark energy and dark matter by accurate measurements of both the accelerated expansion of the Universe and the strength of gravity on cosmological scales.

Mission
Euclid is a space telescope designed to explore the dark Universe. The mission will map out the large-scale structure of the Universe across 10 billion light years, revealing the history of its expansion and the growth of structure during the last three-quarters of its history.

ESA's Cosmic Vision 2015-2025

Launch date: 2020

What’s special?
Euclid will map the 3D distribution of up to two billion galaxies and dark matter associated with them, spread over most of the sky outside our Milky Way.

Euclid is optimised to tackle some of the most important questions in modern cosmology: How did the Universe originate and why is it expanding at an accelerating rate, rather than slowing down due to the gravitational attraction of all the matter in it?

The discovery of this cosmic acceleration in 1998 was rewarded with the Nobel Prize for Physics in 2011 and yet we still do not know what causes it. The term 'dark energy' is often used to signify this mysterious force, but by using Euclid to study its effects on the shapes and locations of galaxies across the Universe, astronomers hope to come much closer to understanding its true nature and influence.

Spacecraft
Euclid comprises a 1.2m diameter telescope and two scientific instruments: a visible-wavelength camera and a near-infrared camera/spectrometer.

Journey
Euclid will launch on a Soyuz vehicle from Europe's Spaceport at Kourou, French Guiana.

It will orbit around the Sun, at an average distance of 1.5 million km beyond Earth’s orbit. This special location, known as the L2 Lagrangian point, keeps pace with Earth as we orbit the Sun.

Euclid’s nominal mission lifetime is six years.

Euclid logo

History
Euclid emerged from two mission concepts that were proposed in response to the ESA Cosmic Vision 2015-2025 Call for Proposals, issued in March 2007: Dune, the Dark Universe Explorer, and Space, the Spectroscopic All Sky Cosmic Explorer. Both missions proposed complementary techniques to measure the geometry of the Universe, and after an assessment study phase, a combined mission resulted. The new mission concept was called Euclid, honouring the Greek mathematician Euclid of Alexandria (~300 BC) who is considered as the father of geometry.

In October 2011 Euclid was selected by ESA’s Science Programme Committee for implementation, and in June 2012 it was formally adopted.

Partnerships
Nearly 1000 scientists from 100 institutes form the Euclid Consortium building the instruments and participating in the scientific harvest of the mission. The Euclid Consortium comprises scientists from 13 European countries: Austria, Denmark, France, Finland, Germany, Italy, Netherlands, Norway, Spain, Switzerland, Portugal, Romania and the UK. It also includes a US NASA team of scientists.