Live coverage: SpaceX Falcon Heavy launches NASA’s Psyche on mission to a metal asteroid

SpaceX simulated an in-flight emergency Sunday to verify the company’s Crew Dragon spacecraft has the capability to catapult away from a failing Falcon 9 rocket.

After four years of brainstorming, custom tool development and training, two astronauts plan to venture outside the International Space Station Friday for the first of four spacewalks to repair a $2 billion cosmic ray detector. The excursions are considered the most challenging since work to service the Hubble Space Telescope.

Officials from NASA, research institutions and companies involved in the development and launch of the Transiting Exoplanet Survey Satellite briefed reporters in the mission Sunday, the day before its scheduled liftoff from Cape Canaveral.