NASA has agreed to provide infrared detectors for the European Space Agency's Euclid dark energy mission, a contribution worth approximately $50 million which buys U.S. scientists membership in a consortium of researchers steering the project's scientific objectives.

Artist's concept of the Euclid spacecraft. Credit: ESA
 
The Euclid mission, due to launch in 2020, is devoted to unraveling the nature of dark matter and dark energy, two constituencies making up more than 95 percent of the universe. Euclid will carry two science instruments and a 3.9-foot telescope to map the shape, distribution and brightness of two billion galaxies up to 10 billion years old.

Euclid will chart the rate of the universe's expansion over the last three-quarters of its history. Scientists attribute the universe's accelerating expansion to dark energy, a mysterious force comprising more than two-thirds of the mass-energy content in the cosmos.

Traditional matter, the stuff we can see and touch, makes up 4 percent of the universe. Dark matter, a more exotic set of poorly understood, invisible particles, fills a quarter of the universe.

Dark energy makes up about 70 percent of the composition of the cosmos. It's enough to counteract the gravitation pull of normal matter and dark matter, forcing the frontiers of the universe outward and accelerating the rate of its expansion.

Euclid will address the origin of dark energy, helping scientists determine if the force is a cosmological constant, an exception to Einstein's theory of general relativity, or some other property. During its six-year mission, Euclid will also yield clues about the fate of the universe.

NASA will provide 16 infrared detectors and four spare detectors for one of Euclid's two science instruments, the space agency announced Thursday.

"NASA is very proud to contribute to ESA's mission to understand one of the greatest science mysteries of our time," said John Grunsfeld, associate administrator for the agency's science mission directorate.

Euclid will cost ESA more than 600 million euros, or about $808 million. ESA's member states, funding the mission outside of ESA's collective framework, will fund nearly 25 percent of Euclid's cost.

Europe's financing, coupled with the value of NASA's contributions, will put Euclid's total cost at about $1 billion.

The 4,600-pound spacecraft is scheduled to launch on a Soyuz rocket in 2020. It will be stationed at the L2 Lagrange point one million miles from Earth.

NASA has nominated 40 scientists for the Euclid Consortium, an international group of 1,000 scientists overseeing development of Euclid's instruments and in charge of analyzing data from the mission after its launch.

"ESA's Euclid mission is designed to probe one of the most fundamental questions in modern cosmology, and we welcome NASA's contribution to this important endeavor, the most recent in a long history of cooperation in space science between our two agencies," said Alvaro Gimenez Canete, ESA's director of science and robotic exploration.

NASA is working on a U.S.-led mission to study dark energy. The Wide-Field Infrared Survey Telescope, or WFIRST, could launch by 2025 with adequate funding, according to NASA officials.