Euclid design approved, ESA mission will explore the “Dark Universe”

Last year was crucial for Euclid, the European Space Agency (ESA) mission to investigate the “Dark Universe” (mainly the largely unknown “dark energy”, thought to be responsible for the accelerating expansion of the universe). Euclid has now passed its Preliminary Design Review (PDR), allowing actual construction of the spacecraft and its payload to start. Satellite prime contractor Thales Alenia Space completed the selection of its industrial partners in 2015: more than 100 companies from 18 European countries will build components for this spacecraft.

One of the primary focuses in astrophysics today is improving our knowledge of dark matter and energy. Euclid will contribute to this research by surveying the extragalactic sky, free from the contamination of light from our own Solar System and galaxy. It will be fitted with a 1.2-meter-diameter telescope that feeds two instruments, a visible imager (VIS) and a near infrared spectrometer and photometer (NISP). The survey will be organized in small squares, measuring half a degree on a side, each of which will be observed by the telescope for about one and a half hours, in different modes. The spacecraft will be positioned at the second Lagrange point of the Sun-Earth system (L2), approximately 1.5 million kilometers from the Earth.

ESA and Thales Alenia Space signed the original contract in 2013, designating Thales Alenia Space as prime contractor for the satellite. The basic design requirements are optical system quality and stability, acquisition speed and completeness, pointing accuracy and stability, and data transmission reliability. The design proposed by Thales Alenia Space Italy is based on its experience with the Herschel/Planck mission, which offered excellent performance in orbit, along with an innovative, agile and precise pointing system and state-of-the-art telecommunications capabilities.