Two mirrors, each small enough to fit in the palm of your hand, are set to change how we understand the cosmos.

The launch window for NASA’s Nancy Grace Roman Space Telescope is about to open. The telescope’s primary instrument is due to inform practically every area of astrophysics, but also tucked inside the telescope is a specialized coronagraph, an experimental apparatus that will attempt to directly capture starlight reflected off a planet’s surface for the first time. It’s an ambitious project that NASA hopes will pave the way for a space telescope that can one day provide a glimpse of an Earthlike planet orbiting a sunlike star.

That’s a feat far beyond the power of current engineering—hence taking the basic technique for a spin on Roman. “We’ll test them in space for the first time, and we’ll understand what work still is left to go,” says Vanessa Bailey, an astrophysicist at NASA’s Jet Propulsion Laboratory and instrument scientist for the coronagraph.

At its core, a coronagraph is just a science-minded sunshade that can block out the light of a bright star and reveal a fainter object otherwise lost in the glare. Such instruments have flown in space before—both the Hubble and James Webb space telescopes carry coronagraphs. But Roman’s is light-years more sophisticated than its predecessors, thanks largely to technology called adaptive optics, which deforms a telescope’s mirror to cancel out these light distortions. It still faces a monumental challenge, though: NASA compares the task of Roman’s coronagraph to photographing a firefly perched next to a floodlight—from across the country.