GLOSSARY

Abort
to cut a mission or activity short due to a serious problem that arises during flight

Aerodynamics
the science that deals with the motion of air and other gases; also, the science of the forces acting on bodies when the bodies move through air or other gases

Aerodynamic forces
the forces exerted by moving air or other gases upon a body completely immersed in those gases

Air pressure
the force created by air confined in a restricted space

Airlock
a chamber that can be completely sealed and provides for passage between two places of different pressure (for example, between the pressurized interior of the International Space Station and the vacuum of space); the station's airlock allows astronauts to carry out spacewalks even when a space shuttle is not docked at the station

Asteroid
one of the many small celestial bodies revolving around the sun; some are hundreds of kilometres in diameter, while others are too small to measure; most asteroids are in orbit between the orbits of Mars and Jupiter

Atmosphere
the envelope of air surrounding the Earth; also the body of gases surrounding or making up any planet or other celestial body

Aviation
the skill or practice of aircraft operation; the designing and building of aircraft

Ballistic rocket
a missile that operates according to the laws of ballistics (see ballistics definition below); a rocket or missile that is guided during part of its flight (usually the upward portion) and is under no thrust from its propelling system during the latter part of its flight; the path taken by a ballistic missile is similar to that of an artillery shell

Ballistics
the science that deals with the motion, behaviour, and effects of projectiles, especially bullets, aerial bombs, and rockets

Barnstormer
a pilot who carries out stunt-flying performances

C.E.
abbreviation of Common Era, used to indicate years A.D.; e.g. World War I began in 1914 C.E.

Circumference
the distance around a spherical object

Civilian
a person who is not in the armed forces or police

Clearcut logging
the logging practice of cutting down all trees in an area, instead of just selected ones

Cold War
term used to describe the power struggle between the Western states (the United States, Great Britain, Western Europe, and their allies) and the Communist powers (the Soviet Union and its allies) from the end of World War II to 1989; in a cold war, opponents use political, economic, and psychological tactics instead of military action

Comet
a luminous celestial body that is made up of a head (a nucleus of ice, frozen gas, and dust, surrounded by a hazy cloud) and often a spectacular gas tail extending a great distance from the head; comets travel in oval orbits around the sun

Composition
the make-up of anything; for example, the air we breathe is composed of nitrogen, oxygen, argon, carbon dioxide, and small quantities of inert gases

Cosmic rays
high-energy, electrically charged particles (mostly protons) that travel the solar system at almost the speed of light and bombard Earth from all directions; it is believed that some originate in the sun (solar cosmic rays), while others originate outside the solar system (galactic cosmic rays); the radiation they produce in space is dangerous to astronauts

Cosmonaut
Russian term for astronaut

Depressurize
depressurize: to decrease the atmospheric pressure inside a spacecraft or spacesuit; this could easily be fatal for astronauts, as the air they need would escape into the vacuum of space

Ethanol
ethyl alcohol; commonly known as grain alcohol

Elevation
the height of a landform or flying object

Fuselage
the main body of an aircraft; wings are attached to the fuselage

Geostationary
an orbit in which an artificial satellite remains above the same point on the Earth's surface

Glide
a controlled descent by a heavier-than-air aircraft or spacecraft under little or no engine thrust; forward motion is maintained by gravity and vertical descent is controlled by lift forces

Glider
a fixed-wing aircraft specially designed to glide; ordinarily, this kind of aircraft does not create its own power

Gravity
a force that attracts objects toward the centre of Earth or other celestial bodies; an invisible force that pulls things toward each other

Gunpowder
a powder that explodes upon contact with fire; used in guns, fireworks, and blasting

Habitat module
section of the International Space Station in which astronauts will eat and sleep

Latitude
the distance of a location north or south of the planet's equator; latitude is measured in degrees; most of the border separating Canada and the United States is 49 degrees north of the equator--that's why it is called "the 49th parallel"

Lift
force exerted on a wing (or other airfoil) by a flow of air over and around it; lift acts at right angles to the direction of flight; the force opposed to gravity

Longitude
the east-west location of a place, measured in degrees; longitude is based on the zero-degree line of longitude that runs through Greenwich, England; a location's longitude determines what time of day it is in relation to other places

Lunar
of or having to do with the moon

Magnetic field
a region of space around a magnetic body (such as the Earth or sun) where magnetic forces can be detected

Magnetic observatory
an observatory that uses special equipment to monitor the Earth's magnetic field

Meteorite
any meteoroid (see meteoroid definition below) that has reached the surface of Earth without being completely vaporized

Meteoroid
a solid object moving in outer space, of a size considerably smaller than an asteroid and considerably larger than an atom or molecule

Microbes
tiny living organisms such as bacteria or microscopic fungi

Microgravity
term used to describe the relative weightlessness of outer space; there is some gravity in space--for example, the force exerted by the planets, moon and sun--but it is too slight for people to notice without special instruments; astronauts experience microgravity aboard a spacecraft orbiting Earth

Micrometeorites
a very small meteorite with a diameter (in general) less than a millimetre

Module
a self-contained unit of a launch vehicle or spacecraft that serves as a building block for the overall structure; a module is usually named after its main function, such as command module, lunar landing module, habitation module, etc.

Molten
liquid, due to high temperature and pressure; the term is usually used to describe rock or metal

Nodes
passageways that connect various modules of the International Space Station

Nucleus
solid part of a comet's head, made up of ice, frozen gas, and dust

Observatory
building or place equipped with a telescope and/or other equipment for observing stars and other celestial bodies

Oceanographic
of the exploration and study of the world's oceans; of the science of the sea

Orbit
the curved path an object (such as a satellite or spacecraft) follows as it travels through outer space around a planet, moon, or other celestial body; also, one complete trip around the Earth along this path is called an orbit

Plates
the extremely large pieces of the Earth's crust that together make up our planet's surface

Pressure
atmospheric pressure; the pressure at any point in an atmosphere due solely to the weight of the atmospheric gases above the point concerned

Propellant
rocket fuel, commonly in either liquid or solid form

Radar
acronym for RAdio Detection And Ranging; by bouncing electronic signals off of an object, radar can tell how far away the object is and how fast it is moving; some kinds of radar are used in photography and mapping

Radiation
the emission of energy as waves or as moving particles; examples of radiation include heat, light, and x-rays

Rendezvous
a French word meaning "to have a meeting"; the space program uses the word to mean "two objects meet in space"

Resolution
amount of detail that can be seen

Rocket
a projectile, pyrotechnic device (e.g. fireworks), or flying vehicle propelled by one or more solid- or liquid-fuel engines; a rocket does not require intake of air or oxygen, as it contains everything needed for its operation

Rover
a remote-controlled surface vehicle

Satellite
an object that is bound by gravity to orbit another, larger object; for example, the moon is a satellite of Earth; human-made satellites are launched into orbit for communications and observation of the planet and outer space

Sediment
fine sand and organic matter that is swept along by moving water and eventually settles to the bottom

Solar arrays
wing-like structures that convert the sun's energy into electrical power; also known as solar panels

Solar flares
tremendous explosions from relatively small areas on the sun; these bright outbursts shoot material from the sun out into space

Solar panel
device that uses the sun's energy to generate electricity; a solar panel contains solar cells, small units that convert light into electrical energy; also known as solar arrays

Solar wind plasma
the continuous flow of charged particles (e.g. protons and electrons) coming out of the sun; these particles travel in all directions at very high speeds (on average, about 400 kilometres per second or 1 million miles per hour); solar wind plasma is responsible for the shape of the magnetic fields around the planets; solar wind can also affect the flight paths of spacecraft

Sound barrier
the speed of sound (about 1192 km/h or 740.7 mph); also, the increased drag and difficulty in control that planes experience as they approach the speed of sound

Space age
current period of history, marked by the first efforts of human beings to explore outer space; the space age began on October 4, 1957 when the Soviet Union launched the world's first satellite, Sputnik 1

Space race
competition between the United States and Soviet Union over developments and achievements in space exploration; the space race began on October 4, 1957 when the Soviet Union launched the world's first satellite, Sputnik 1

Spacewalk
any activity performed by astronauts in space outside their spacecraft; also known as extravehicular activity (EVA)

Suborbital
being or involving less than one full orbit of the Earth

Thrust
force exerted in one direction that sends an object in another direction (e.g. the forced ejection of gases from the rear of a rocket that propels the rocket forward)

Trajectory
the path of a spacecraft or rocket during ascent, orbit, or landing

Truss
a bridge-like, linear structure; all parts of the International Space Station will be attached to the truss

Vacuum
the almost total absence of gases in outer space; most gas molecules are pulled toward the surface of stars and planets (e.g. Earth's atmosphere), leaving the space between nearly empty

Warhead
the explosive cap of a missile, torpedo, or similar weapon

Weightlessness
term used to describe the apparent lack of gravity in outer space; there is some gravity in space--for example, the force exerted by the planets, moon and sun--but it is too little for people to notice without special instruments; astronauts experience weightlessness aboard a spacecraft orbiting Earth; also known as microgravity