The first government contract for a commercial rocket launch is in the hands of a company directed by one of the original Mercury astronauts, who is eager to send a scientific payload into space next year.

Space Services Inc. of Houston will get $1 million to fire its two-stage Starfire rocket on a sub-orbital mission in March from White Sands Missile Range, N.M., according to the National Aeronautics and Space Administration."We're delighted," said company President Deke Slayton after NASA officials made the announcement. "We've been working on commercial launches for a long time."

Slayton, one of the seven original Mercury astronauts, was grounded in the early 1960s because of an irregular heartbeat but later was cleared for flight and commanded the 1975 Apollo-Soyuz mission in which he and two other American astronauts docked with two Soviet cosmonauts.

Explaining his company's success to a news conference in Cocoa Beach, Fla., Slayton said, "Our main line of course is still doing orbital launches. But we became aware of some of these sub-orbitals . . . so we view that as something we know how to do very well, and we might as well pursue that too."

The black, white and gray Starfire stands 55 feet including its payload and is propelled by solid fuel. Its lower stage was built by the Morton Thiokol Co. of Brigham City, Utah.