Clone: The asexual creation of an exact replica of another individual, using any body cell except a sperm or ovum: a process known as cloning. The problems of being a clone are strikingly delineated by Kate Wilhelm in "Where Late the Sweet Birds Sang", and by Nancy Freedman in "Joshua, Son of None." The basic thesis of cloning is that all genetic information required to reproduce an organism is encoded in the nucleus of each living cell. The word clone is from a Greek term meaning botanical twig or shoot.

Doppler Navigation: Spatial orientation determined by measuring doppler-effect echoes from spacecraft-originated radiant energy beams. Gives a continuous indication of position.

Fishbowl Effect: A term coined by Ted Krulik, a New York science fiction instructor. A goldfish, contentedly swimming in a tank, regards that restrictive environment as his familiar, non-thought-provoking "universe". If the fish is yanked from the water, it is exposed to an astonishingly different gestalt, which theoretically kindles fresh perspectives. Jerking readers from their individual fishbowls and exposing them to new gestalts is one of science fiction’s functions- the igniting of wonder mixed with expanded comprehension. In Daniel Keyes’s "Flowers for Algernon", Charlie Gordon becomes a "fish out of water", able to perceive his previous limited world, and comprehend his newly expanded world, with incisive insights.

G Force: Strong inertial force exerted on a person or object - by gravity or reaction to acceleration or deceleration - stemming from abrupt directional changes. Normally expressed in multiples of terrestrial gravity. (One G is the gravitational pull needed to accelerate a falling body 32.2 feet-per-second.) The effect on a spaceman would be most obvious in an overly sudden power dive or upswing. Due to centrifugal pressure on his bones, flesh, and blood his face would flush and he would see red before his eyes at three or four G’s. At five or more G’s, he would black out, recovering consciousness only when the centrifugal force faded as the spacecraft leveled out.

Launch Window: The exact spot from which - and precise time at which - a spacecraft must be launched to implement a desired rendezvous, encounter, impact, or other mission. In addition, a proper window must be calculated for re-entry.

Milk Run: Slang for an uneventful space fligh

Robot:   The word derives from a Czechoslovakian term for "worker", and was first used by Karel Capek in his play, "R.U.R.", produced in 1921. R.U.R. means "Rossum’s Universal Robots". These initial robots were essentially man-like androids mass-produced chemically. (In a pure sense, android is a science fiction term for a human-appearing robot, as opposed to a metal one, though the distinction is frequently ignored.) Capek wasn’t the first writer whose theme was the creation of artificial life. He’d been preceded by Mary Shelley, with "Frankenstein"; and by Ambrose Bierce, with "Moxon’s Master".

Scrub:   To cancel - for any of a variety of reasons - a scheduled spacecraft launching before or during countdown.

Thermodynamics: First Law of Energy can neither be created nor destroyed: it merely changes place or form.

Umbra: On a non-self-luminous celestial body, such as a planet or moon, the darkest part of a shadow from which all light is cut off.