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dwarf tree

(Encyclopedia)dwarf tree, in horticultural practice, a tree artificially kept to a smaller size than is normal for average members of the species. This is usually accomplished either by limiting its root space and ...

NASA

(Encyclopedia)NASA: see National Aeronautics and Space Administration. ...

Sagan, Carl Edward

(Encyclopedia)Sagan, Carl Edward sāˈgən [key], 1934–96, American astronomer and popularizer of science, b. New York City. Early in his career he investigated radio emissions from Venus and concluded that the c...

Strategic Air Command

(Encyclopedia)Strategic Air Command (SAC), former command of the U.S. air force (see Air Force, United States Department of the) charged with organizing, training, equipping, administering, and preparing strategic ...

European Astronaut Center

(Encyclopedia)European Astronaut Center (EAC): see European Space Agency. ...

European Launcher Development Organization

(Encyclopedia)European Launcher Development Organization (ELDO): see European Space Agency. ...

pump

(Encyclopedia)pump, device to lift, transfer, or increase the pressure of a fluid (gas or liquid) or to create a vacuum in an enclosed space by the removal of a gas (see vacuum pumps under vacuum). The centrifugal ...

Ultima Thule

(Encyclopedia)Ultima Thule, in astronomy and space exploration, nickname for Arrokoth. ...

Mather, John Cromwell

(Encyclopedia)Mather, John Cromwell, 1946–, American astrophysicist, b. Roanoke, Va., Ph.D. Univ. of California, Berkeley, 1974. He has been a researcher at NASA's Goddard Space Flight Center in Greenbelt, Md., s...

Shepard, Alan Bartlett, Jr.

(Encyclopedia)Shepard, Alan Bartlett, Jr., 1923–98, American astronaut, b. East Derry, N.H., grad. Annapolis, 1944. He served on a destroyer during World War II and later had extensive experience as a test pilot....