Ellison Shoji Onizuka (Japanese: エリソン・ショージ・オニヅカ, 鬼塚 承次, Hepburn: Onizuka Shōji, June 24, 1946 – January 28, 1986) was an American astronaut, engineer, and U.S. Air Force flight test engineer from Kealakekua, Hawaii, who successfully flew into space with the Space Shuttle Discovery on STS-51-C.

Onizuka had two older sisters, Shirley and Norma, and a younger brother, Claude, who became the family spokesman after the Challenger disaster.

Onizuka participated in U.S. Air Force ROTC during his time there and is an alumnus of Triangle Fraternity, as well as a member of the Tau Beta Pi honor society.

At NASA, Onizuka worked on the Shuttle Avionics Integration Laboratory (SAIL) test and revision software team.

During the mission, Onizuka was responsible for the activities of the primary payloads, which included the unfolding of the Inertial Upper Stage (IUS) surface.

The shuttle was destroyed when a flame jet leaking from a solid rocket booster ruptured the liquid hydrogen fuel tank 73 seconds after launch.

Following the Challenger disaster, examination of the recovered vehicle cockpit revealed that three of the crew members' Personal Egress Air Packs were activated: those of Onizuka, Resnik, and Smith.

[14] Onizuka belonged to the following organizations: Society of Flight Test Engineers, the Air Force Association, the American Institute of Aeronautics and Astronautics, Tau Beta Pi, Sigma Tau, Arnold Air Society, and Triangle Fraternity.

They not only feature Onizuka's personal items, but also the only Moon rock in Hawaii and the space suit from Apollo 13 astronaut Fred Haise.

(At the time of the Challenger disaster, his older daughter, Janelle, attended Clear Lake High School.

It includes a Visitor Information Station as well as dining, lodging, office, and maintenance facilities for observatory staff and astronomers.

Smead Aerospace Engineering Sciences building at the University of Colorado at Boulder features a conference room named after Onizuka on the third floor.

[22] The students at the United States Air Force Test Pilot School present the Onizuka Prop Wash Award to the classmate who contributed most to class spirit and morale.

Morikami Museum and Japanese Gardens has a memorial and lamp dedicated to the seven astronauts who died on the Challenger, including Ellison Onizuka.