Geometry runs back thousands of years and it is no coincidence that the ESA's mission that just took off from Cape Canaveral was named after the Greek mathematician and philosopher Euclid of Alexandria, who is best known for his postulates that have revolutionized the measurement of space. Euclid is one of ESA's most ambitious scientific endeavors in which Italy, through the Italian Space Agency (ASI), the National Institute of Astrophysics (INAF) and the National Institute of Nuclear Physics (INFN) is playing a leading role.

Euclid is equipped with a 1.2 m reflecting telescope and two scientific instruments: the VISible instrument, (VIS) the Near-Infrared Spectrometer and Photometer, (NISP). They are designed to provide very sharp images of a large fraction of the extragalactic sky and perform near-infrared spectroscopy of hundreds of millions of galaxies and stars over the same sky.Euclid's overarching scientific goal is to reach a detailed understanding of dark matter and dark energy, that are among the most intriguing themes of modern astrophysics since these two mysterious and invisible components make up 95% of the Universe. The mission will be able to fulfil its goal by observing and studying two different and independent cosmological phenomena: weak gravitational lensing, that is the apparent distortion of the images of distant galaxies induced by the light passing through non-uniform distribution of dark matter along the line of sight, and acoustic oscillations in the visible baryonic matter of the universe and the clustering pattern of galaxies.

This two-tier study will condition the equation describing the properties of dark energy thus revealing, for instance, whether it evolves with cosmic expansion or whether changes to Einstein's general relativity theory should be considered. Euclid, with a mass in orbit of 2 tonnes, took off today onboard SpaceX Falcon 9 from Cape Canaveral’s Space Launch Complex 40. In the next weeks, it will travel towards Sun-Earth Lagrange point 2, one of the equilibrium points of the Sun-Earth system located 1.5 million km beyond Earth’s orbit..

Teodoro Valente, president of the Italian Space Agency said: "Today we're celebrating yet another major scientific and industrial achievement in Space. The Euclid mission will pave the way to a new understanding of ourselves and the Universe around us. Missions such as this are further proof of the role scientific research plays in advancing knowledge and promoting growth as a whole. This is a most important program which the Agency is part of coordinating a remarkable group of national entities and through it conferring their outstanding expertise and knowledge to such an ambitious European project securing our country a lead actor role. Over 200 Italian scientists and researchers are involved in the project. It is proof of excellence that gives prestige to Italy's Space endeavors".

The Italian Space Agency in cooperation with the National Institute of Astrophysics (INAF) and the National Institute of Nuclear Physics (INFN) has led the industrial team that designed and built the contributions Italy to the mission. A temporary association of company was set up with OHB as agent and SAB Aerospace and Temis as principals. ESA selected Thales Alenia Space Italia of the Leonardo group as prime contractor for the construction of the satellite and its Service Module.

Antonio Zoccoli, INFN president, said: "Euclid is the Institute's first project dedicated to dark matter. The INFN has contributed to the development of the NISP and will be involved in the analysis of the data the telescope will collect, also providing computing resources with the main objective of studying dark matter and measuring neutrino mass. Research on dark matter is new to our Institute whose flagship research regards direct and indirect measurements of neutrino properties.Thanks to the participation in the Euclid mission, the INFN will be able to incorporate a new type of data acquired through astrophysical technologies into its long standing traditional activities." Moreover the Italian Agency also supports the INAF in the key role it plays at the helm of the Science Ground Segment (SGS), as well as in the development of the software of the two on-board instruments and supporting all of the research entities participating in the activities of the Science Working Groups. Finally, the agency has selected ALTEC for the industrial activities of designing and developing Italy's Euclid INAF-led Science Data Center. The INFN will provide INAF with further computing resources to analyse data and carry out simulations on scientific results.

Marco Tavani, INAF president said: "The Euclid mission ushers in a new era in cosmology. It is unsettling to think that 95% of our Universe continues to elude us, despite the enormous breakthroughs that have been made over the past decades in understanding the cosmos. What is the nature of the mysterious dark matter, which holds all cosmic structures together and seems to outweigh visible matter roughly five to one? And what about dark energy, which is even more elusive and that drives the current accelerated expansion of the cosmos? These are the fascinating questions that Euclid, an incredible European space mission, in which Italy is one of the key participants, will address. Italy is responsible for about a quarter of all the effort required to build and operate the satellite, as well as drawing on the mission's scientific results. The National Institute of Astrophysics has to perform the prestigious and delicate task of leading the entire Science Ground Segment, which coordinates the processing and analysis of the immense amount of data collected by the probe and fed to Earth. INAF has also designed the software for the two on-board instruments, the scientific brain of the mission, and will manage the operations of one of them, the NISP, the near-infrared spectrograph, once in orbit."

Over 200 Italian scientists, women and men from INAF, INFN and several universities, such as University of Bologna, University of Ferrara, University of Genoa, Università Statale di Milano, University of Rome "Roma Tre", University of Trieste, SISSA, CISAS, have come together to take part in the Euclid mission.The launch will be followed by an intense three-month period of testing and calibration of the spacecraft and its scientific instruments in preparation for the observations. Euclid will observe a third of the sky with unprecedented accuracy and sensitivity over a period of six years. By the end of its nominal mission lifetime, which currently is estimated to be around six years, Euclid will have taken images and photometric data of more than a billion galaxies and millions of galaxy spectra. They will be fundamental also to promote the advancement of many other astrophysical sectors. The Italian Space Agency also participated in the launch operations. It tracked the satellite from its Luigi Broglio Space Centre in Malindi, Kenya. The ground stations of the Broglio Space Centre are located in a privileged position to allow then to monitor the key events of the mission. The Malindi Center has provided support activities from the early stages of the mission tracking the Falcon 9 launcher's trajectory and acquiring Euclid's first signal just 30 minutes after take-off, and then monitoring for up to six hours after the launch.