In 2010 Soares-Santos became a Research Associate in Astrophysics at the Fermi National Accelerator Laboratory, in Batavia, near Chicago. Her research at Fermilab was focused on the characteristics of gravitational waves and in dark energy. There, Soares-Santos contributed to the construction of the Dark Energy Camera, one of the largest telescope cameras in the world, which she employed to search for gravitational wave-emitting collisions of neutron stars and black holes. Work at Fermilab continued until 2017, when she became assistant professor of Physics in Brandeis University.