Ryker, the son of an interior painter, was born in Tacoma, Washington, and received an MS degree in engineering from the University of California at Berkley in 1951. He then went to work for North American Aviation's Rocketdyne rocket engine division. The slender, crew-cut engineer was working in North Americans' missile division in 1960 when he was selected by Harrison Storms to head up the company's Apollo proposal effort.
He supervised the proposal group by putting his desk on the stage at the front of the company auditorium where the team of hundreds was working. After North American won the Apollo spacecraft award, he was named assistant chief engineer under Charlie Feltz. Ryker's design for an outward-, quick-opening hatch for the spacecraft was rejected by NASA, sealing the fate of the Apollo 1 astronauts six years later. He headed the gruelling contract negotiations for the program with NASA, ending up suffering a heart attack from the stress in 1965.
He took up a strict regimen of diet and exercise thereafter, and in 1976 was named president of the Rocketdyne Division of what was by then part of the Rockwell International Corporation. He led the rocket team there until 1983, developing and flying the Space Shuttle Main Engine.
He left Rocketdyne in 1983, taking executive positions at the Pneumo and Cross and Trecker corporations, before retiring in 1991.
Birth Place: Tacoma, Washington.