NASA is preparing to launch its next flagship space observatory — one scientists plan to use to investigate some of the universe’s biggest mysteries, including dark energy and dark matter, while also testing gravity at vast scales and hunting ​for planets beyond our solar system.

The Nancy Grace Roman Space Telescope is a roughly $4 billion project. At the time of writing, it was planned for a Sunday launch from the NASA Kennedy Space Center in Florida. The observatory will be lofted into orbit aboard a SpaceX Falcon Heavy rocket.

The telescope is named after the late Nancy Grace Roman, NASA’s first chief astronomer. It is a follow-on to the Hubble Space Telescope, launched in 1990, and the James Webb Space Telescope, launched in 2021, and has capabilities that can expand on the knowledge gained by those pioneering observatories, both of which also still operate.

The telescope’s main survey will take more than ​a year, per Roman’s senior project scientist Julie McEnery.

“The survey will contain over two billion galaxies and enable us to study how the structures in our universe — the stars, the galaxies, the clusters of galaxies — grew and evolved. We’ll ​also measure how our universe has expanded over time,” she said.

After launch and separation from the rocket, the telescope will travel towards a location called Lagrange point 2, about 1.6 million km from the earth. Webb also resides at this location.

U.S. ​President Donald Trump tried during both his first and second terms to reduce or eliminate funding for Roman but Congress preserved it.