NASA Prepares to Launch New Roman Space Telescope

The telescope has a surprising history. Around fifteen years ago, NASA was designing an instrument to hunt exploding stars called supernovas. At that moment the National Reconnaissance Office (NRO), the agency that runs American spy satellites, offered NASA a spacecraft it had never used. The suggestion was simple: point it up at the sky instead of down at Earth. After heavy modification, that spare satellite became a major science mission. Roman sees as sharply as the Hubble Space Telescope, but its field of view is at least a hundred times wider. Project scientist Julie McEnery says one month of Roman observations would survey the Milky Way galaxy, work that would keep Hubble busy for about a century.

Scientists want Roman to measure dark energy, the mysterious force pushing the universe apart, and to test whether current ideas about that expansion are right. It should also map billions of galaxies, study black holes and find planets that other methods cannot see. Scott Gauti of Ohio State University expects it to spot distant worlds through gravitational microlensing. Albert Einstein described that effect in 1936 but thought it would never be practical. The mission should last five years, and its catalogues will be public.