The Roman Space Telescope launches August 30. Here is what it is going after.

The Nancy Grace Roman Space Telescope is launching on August 30, 2026. That is eight months ahead of its previously planned date, which is a meaningful rescheduling for a mission that has been in development for over a decade. It will ride a SpaceX Falcon Heavy from Kennedy Space Center to the Sun-Earth L2 point, around 1.5 million kilometres from Earth.

Roman is a different kind of telescope to Webb. Where Webb stares at single targets in extraordinary depth, Roman takes wide-angle surveys. Its field of view is more than 100 times larger than Hubble's, and it can cover the same area roughly 1,000 times faster while maintaining comparable sensitivity in infrared wavelengths.

The headline science goals are substantial. Over its planned five-year mission, Roman expects to measure light from roughly a billion galaxies, giving cosmologists the statistical power to say something definitive about dark energy. Nobody knows what dark energy actually is. It appears to be accelerating the expansion of the universe. Roman's survey data should either confirm the standard model or crack it open.

Dark matter is the other target. By mapping how light from distant galaxies is distorted by mass between them and us (gravitational lensing), Roman will build the most detailed map yet of where invisible mass is hiding in the universe.

The exoplanet programme runs alongside. A microlensing survey of the inner Milky Way is expected to detect more than 1,000 exoplanets, including free-floating worlds that orbit no star. Roman will also directly image nearby exoplanets by blocking starlight with a coronagraph, a technology being tested at operational scale for the first time.