NASA has officially joined the European Space Agency’s Euclid mission, a space telescope that will launch in 2020 to study the mysterious dark matter and dark energy pervading the universe.

NASA will contribute 16 infrared detectors and four spares for one of the Euclid telescope‘s two planned science instruments, agency officials announced today (Jan. 24). NASA has also nominated 40 new members for the Euclid Consortium, an international body of 1,000 scientists that will oversee the mission and its development.

“NASA is very proud to contribute to ESA’s mission to understand one of the greatest science mysteries of our time,” John Grunsfeld, associate administrator for NASA’s Science Mission Directorate, said in a statement.

Astronomers think the “normal” matter we can see and touch makes up just 4 percent of the universe. The rest is comprised of dark matter and dark energy — strange stuff whose existence scientists infer from its influence on the 4 percent.

Dark energy is especially intriguing, since many researchers believe it to be the strange force responsible for the accelerating expansion of the universe. But just what it is remains a mystery.