[Follow two NASA astronauts’ return trip aboard SpaceX’s Crew Dragon capsule.]

The first crewed mission is a final step for SpaceX to verify that its Falcon 9 rocket and Crew Dragon capsule meet NASA’s requirements. SpaceX conducted a successful demonstration flight — without astronauts aboard — in March last year, but then ran into further obstacles and delays.

In January, SpaceX conducted another critical test, launching the capsule without anyone aboard and deliberately destroying the rocket to show that the escape system was capable of whisking astronauts to safety in case of an emergency.

May’s flight will carry two NASA astronauts: Douglas G. Hurley and Robert L. Behnken. Both have been to space before on space shuttle missions, and Mr. Hurley was the pilot on the last Atlantis mission.

Although NASA has greatly cut back on work at its centers during the coronavirus outbreak — most of its employees are working at home, even for tasks such as directing the Curiosity rover on Mars — the SpaceX flight is regarded as essential work. Florida’s Brevard county, home to NASA’s Kennedy Space Center, has not been among the hardest hit areas so far, reporting 192 cases and six deaths through Friday afternoon.

Currently there are only three astronauts aboard the International Space Station — two Russians, Anatoly Ivanishin and Ivan Vagner, and one NASA astronaut, Christopher J. Cassidy.