Spaceflight Insider

Euclid spacecraft set to unravel the universe’s mysteries

Artist's impression of Euclid. Image Credit: ESA

Artist’s impression of Euclid. Image Credit: ESA

Dark matter and dark energy are two of the greatest mysteries of the universe, perplexing scientists worldwide. Solving these scientific riddles may require a comprehensive approach in which theories, computations and ground-based observations are complemented by a fleet of spacecraft studying the “dark” universe.

One of the space missions that could be essential to our understanding of these mysteries – is the European Space Agency’s (ESA) Euclid probe (which includes contributions from NASA). This space-based telescope is designed to unveil the secrets of dark energy and dark matter by accurately measuring the acceleration of the universe.

The Euclid spacecraft will carry a payload module (depicted in this drawing) with a 1.2-m-diameter telescope and two state-of-the art scientific instruments: a visible-light camera and a near-infrared camera/spectrometer.

The Euclid spacecraft will carry a payload module (depicted in this drawing) with a 1.2-m-diameter telescope and two state-of-the art scientific instruments: a visible-light camera and a near-infrared camera/spectrometer. Image Credit: Airbus Defence & Space

“Euclid is designed primarily to help us understand the properties of dark energy. However, in doing so, it will utilize the exquisite precision only available to a space-based instrument to make measurements of dark matter over an unprecedented area of the sky. Thus, it will be a real breakthrough in our understanding of both dark matter and dark energy,” Ulf Israelsson, NASA Euclid project manager, told

The spacecraft is currently in the construction phase after successfully passing its Preliminary Design Review in the Fall of last year (2015). It is scheduled to be launched in 2020 on a Soyuz rocket from Europe’s Spaceport located in Kourou, French Guiana. After liftoff it will be sent into orbit around the Sun-Earth L2 point which is located approximately 1.5 million kilometers from our world.

In order to help increase our understanding about dark matter and dark energy, Euclid will employ two primary scientific methods.

Artist's impression of Euclid.

Artist’s impression of Euclid. Image Credit: ESA/C. Carreau

“The first is weak gravitational lensing, whereby the apparent shapes of background galaxies are distorted by foreground dark matter. The second is galaxy clustering, looking at the three dimensional distribution of galaxies,” Jason Rhodes, NASA Euclid Deputy Project Scientist and the US Science Lead for Euclid, told SpaceFlight Insider.

The spacecraft will map the shapes, positions and movements of two billion galaxies, delivering astronomers a vast set of important data for further studies. The space-based telescope is expected to produce numerous deep images and spectra over at least half of the entire sky.

To achieve its ambitious scientific goals, Euclid will be equipped with two main instruments: the visible imaging instrument (VIS) and the Near Infrared Spectrometer and Photometer (NISP). These large format cameras will be used to characterize the morphometric, photometric and spectroscopic properties of galaxies.

“Euclid will have two instruments. The first is the visible imaging instrument. It will use a single very wide filter to perform photometry of visible light over a 15,000 square degree area on the sky. The second is the Near Infrared Spectrometer and Photometer. This instrument will use NASA-provided near infrared detectors to perform 3-band photometry in near infrared light over the same 15,000 square degrees as well as providing grism spectroscopy in the near infrared over the same area,” Israelsson explained.

The mission is scheduled to last for some six years and will be tasked with surveying the sky in ‘step-and-stare’ mode. What this means is the telescope will point to a position in the sky; it will then produce imaging and spectroscopic measurements on an area of about 0.5 square degrees around that position.

The wide-survey should cover 15,000 square degrees of extragalactic sky and the deep survey is expected to cover approximately 40 square degrees, consisting of patches of at least 10 square degrees which are about two magnitudes deeper than the wide-survey.

NASA made several contributions to this mission including infrared detectors for one instrument and science and data analysis.

“NASA is providing near infrared detectors and associated electronics for the NISP instrument. NASA is also developing the Euclid NASA Science Center at IPAC [Infrared Processing and Analysis Center], a node in Euclid’s distributed Science Ground Segment that will process the Euclid data. The third contribution is in support of about 70 U.S. scientists who are part of the 1,300 member Euclid Consortium,” Rhodes said.

Video courtesy of the European Space Agency


Tomasz Nowakowski is the owner of Astro Watch, one of the premier astronomy and science-related blogs on the internet. Nowakowski reached out to SpaceFlight Insider in an effort to have the two space-related websites collaborate. Nowakowski's generous offer was gratefully received with the two organizations now working to better relay important developments as they pertain to space exploration.

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