India, Aug. 31 -- Nasa on Sunday launched the Nancy Grace Roman Space Telescope, a $4.3 billion observatory built around a repurposed spy satellite that will scan the universe in wide, panoramic sweeps in an effort to unlock the nature of dark matter and dark energy.

The telescope lifted off from the Kennedy Space Center in Cape Canaveral, Florida, at 7:26 am local time, riding a SpaceX Falcon Heavy rocket through clear skies. The mission is designed to run for five years, though Nasa has said it carries enough fuel to potentially double that lifespan. The spacecraft is also engineered to be refuelled in orbit, an option that could extend its working life further if a robotic tanker becomes available in the coming decade.

The observator...