Euclid (spacecraft)

Euclid is a wide-angle space telescope with a 600-megapixel camera to record visible light, a near-infrared spectrometer, and photometer, to determine the redshift of detected galaxies. It was developed by the European Space Agency (ESA) and the Euclid Consortium, and was launched on 1 July 2023. After approximately one month, it reached its destination, a halo orbit around the Sun-Earth second Lagrange point L2, at an average distance of 1.5 million kilometers beyond Earth's orbit (or about four times the distance from the Earth to the Moon). There the telescope is expected to remain operational for at least six years. It joins the Gaia and James Webb Space Telescope missions at L2. The objective of the Euclid mission is to better understand dark energy and dark matter by accurately measuring the accelerating expansion of the universe. To achieve this, the Korsch-type telescope will measure the shapes of galaxies at varying distances from Earth and investigate the relationship between distance and redshift. Dark energy is generally accepted as contributing to the increased acceleration of the expanding universe, so understanding this relationship will help to refine how physicists and astrophysicists understand it. Euclid's mission advances and complements ESA's Planck telescope (2009 to 2013). The mission is named after the ancient Greek mathematician Euclid. Euclid is a medium-class ("M-class") mission and is part of the Cosmic Vision campaign of ESA's Science Programme. This class of missions have an ESA budget cap at around €500 million. Euclid was chosen in October 2011 together with Solar Orbiter, out of several competing missions. Euclid was launched by a Falcon 9. Euclid will probe the history of the expansion of the universe and the formation of cosmic structures by measuring the redshift of galaxies out to a value of 2, which is equivalent to seeing back 10 billion years into the past. The link between galactic shapes and their corresponding redshift will help to show how dark energy contributes to the increased acceleration of the universe.