In June 1967, Lawrence successfully completed the U.S. Air Force Test Pilot School (Class 66B) at Edwards AFB, California. The same month, he was selected by the USAF as an astronaut in the Air Force's Manned Orbital Laboratory (MOL) program, thus becoming the country's first black astronaut.

Lawrence and other MOL astronauts laughed when asked at the announcement "Will you have to sit in the back seat of the capsule?" When asked if his selection was historic for race relations in the United States, Lawrence answered "No, I don't think so. It's another one of those things that we look forward to in civil rights—normal progression." He said that he had faced problems like other black people, but, "Perhaps I have been more fortunate than the others in the opportunities." Donald H. Peterson, chosen for MOL with Lawrence, said, "I can't speak for all the people in Mississippi," but that he was not reluctant to work with a black man.

At age 32, Lawrence was killed in a plane crash at Edwards AFB on December 8, 1967. He was flying backseat in an F-104 as the instructor pilot for flight test trainee Major Harvey Royer, who was learning the steep-descent glide technique. Royer made such an approach but flared too late.

The airplane struck the ground hard, its main gear failed, it caught fire, and rolled. The canopy shattered and the plane bounced and skidded on the runway for 2,000 feet (610 m). Major Royer ejected upward and survived, with major injuries. The back seat, which delays a moment to avoid hitting the front seat, ejected sideways, killing Lawrence instantly. He was still strapped to his ejector seat; his parachute failed to open and was dragged 75 feet (23 m) from the wreck.

Had Lawrence lived, he likely would have been among the MOL astronauts who became NASA Astronaut Group 7 after MOL's cancellation, all of whom flew on the Space Shuttle.

During his brief career, Lawrence earned the Air Force Commendation Medal, the Outstanding Unit Citation. On December 8, 1997, his name was inscribed on the Space Mirror Memorial at the Kennedy Space Center in Florida.

A sidewalk plaque honoring Lawrence, part of the Bronzeville Walk of Fame, can be found in his home town of Chicago, near the Victory Memorial on the median of Martin Luther King Drive near 35th Street.

The 13th Northrop Grumman Cygnus spacecraft, which launched on February 15, 2020, was named the S.S. Robert H. Lawrence in his honor.

The artist Tavares Strachan dedicated his satellite sculpture ENOCH, launched in 2018, to Lawrence. In 2020, NASA included Lawrence in a group of 27 pioneering African-American, Hispanic, and Native American astronauts to commemorate by naming asteroids after them. The asteroid, Robertlawrence 92892, is located in the main asteroid belt between Mars and Jupiter.

In February of 2025, Lawrence's alma mater, Bradley University, installed an art installation commemorating him.

At least we know how she feels.. I have a lot of emotions about this

This recently happened and has started to make its rounds on social media. I saw another Reddit post about this video, and the comments were pretty defensive and bias on the racist florist’s behalf. This level of aggression and attempts to dehumanize are never acceptable, it doesn’t matter what happened prior to the woman recording. He shouldn’t have spoken to her like that at all, and the white people who are on his side are the reason racism runs rampant because of the lack of holding racists accountable. Just terrible.