0.05 g 60,000 miles Geosynchronous Earth orbit 22,300 miles Hard vacuum 1,000 miles Medium Earth orbit begins 300 miles 0.95 g 100 miles Low Earth orbit begins 60 miles Astronaut wings awarded 50 miles Limit for ramjet engines 28 miles Limit for turbojet engines 20 miles Stratosphere begins 10 miles Earth NASA photo On the following pages appears a variety of information and statistical material about space—particularly military activity in space. This almanac was compiled by the staff of Air Force Magazine, with assistance and information from Dr. R. W. Stur- devant, Air Force Space Command History Office; Tina Thomp- son, editor of TRW Space Log; Phillip S. Clark, Molniya Space Consultancy, Whit- ton, UK; Theresa Foley; and Air Force Space Command Public Affairs Office. SpaceCompiled by Tamar A. Mehuron,Almanac Associate Editor Figures that appear in this section will not always agree because of different cutoff dates, rounding, or different methods of reporting. The information is intended to illustrate trends in space activity. Space Terms Ferret. A satellite whose Polar orbit. Earth orbit with a primary function is to gather 90° inclination. Spacecraft on electronic intelligence, such as this path could pass over every Aerospace. A physical region microwave, radar, radio, and Magnetosphere. A region spot on Earth as Earth rotates made up of Earth’s atmosphere voice emissions. dominated by Earth’s mag- under the satellite’s orbit (see and the space beyond. netic field, which traps charged orbital inclination). Geostationary Earth orbit. A particles, including those in the Aerospace plane. A reusuable geosynchronous orbit with 0° Van Allen belts. It begins in the Remote imaging. Images of spacecraft able to operate ef- inclination in which the space- upper atmosphere, where it Earth generated from a space- fectively in both the atmosphere craft circles Earth 22,300 miles overlaps the ionosphere, and craft that provide data for map- and space. Also known as a above the equator and appears extends several thousand miles ping, construction, agriculture, “transatmospheric vehicle” or, from Earth to be standing still. farther into space. oil and gas exploration, news more currently, “spaceplane.” media services, and the like. Geosynchronous Earth orbit Medium Earth orbit (MEO). Apogee. The point of great- (GEO). An orbit at 22,300 Flight path between LEO, Rocket. An aerospace vehicle est distance from Earth (or the miles that is synchronized with which ends at about 300 miles that carries its own fuel and moon, a planet, etc.) achieved Earth’s rotation. If a satellite in altitude, and GEO, which is at oxidizer and can operate out- by a body in elliptical orbit. Usu- GEO is not at 0° inclination, its an average altitude of 22,300 side Earth’s atmosphere. ally expressed as distance from ground path describes a figure miles. Earth’s surface. eight as it travels around Earth. Semisynchronous orbit. Mesosphere. A region of the An orbit set at an altitude of Atmosphere. Earth’s envelop- Geosynchronous transfer atmosphere about 30 to 50 12,834 miles. Satellites in this ing sphere of air. orbit (GTO). An orbit that miles above Earth’s surface. orbit revolve around Earth in originates with the parking orbit exactly 12 hours. Boost phase. Powered flight of Orbital decay. A condition in a ballistic missile—i.e., before and then reaches apogee at the GEO. which spacecraft lose orbital Single-stage-to-orbit (SSTO) the rocket burns out. altitude and orbital energy system. A reusable single- Burn. The process in which Ground track. An imaginary because of aerodynamic drag stage rocket that can take off rocket engines consume fuel or line on Earth’s surface that and other physical forces. and land repeatedly and is able other propellant. traces the course of another to boost payloads into orbit. imaginary line between Earth’s Orbital inclination. Angle of That section Circumterrestrial space. “In- center and an orbiting satellite. flight path in space relative Stratosphere. ner space” or the atmospheric to the equator of a planetary of atmosphere about 10 to 30 region that extends from 60 High Earth orbit (HEO). Flight body. Equatorial paths are 0° miles above Earth’s surface. path above geosynchronous al- miles to about 50,000 miles from for flights headed east, 180° for An titude (22,300 to 60,000 miles Sun synchronous orbit. Earth’s surface. those headed west. orbit inclined about 98° to the from Earth’s surface). Constellation. A formation of Outer space. Space that equator and at LEO altitude. At satellites orbiting for a specific High-resolution imagery. De- extends from about 50,000 this inclination and altitude, a combined purpose. tailed representations of actual miles above Earth’s surface to satellite’s orbital plane always objects that satellites produce a distance of about 480,000 maintains the same relative Deep space. All space beyond electronically or optically on miles. orientation to the sun. the Earth-moon system, or from displays, film, or other visual The thin atmo- about 480,000 miles altitude devices. Parking orbit. Flight path in Thermosphere. outward. which spacecraft go into LEO, sphere about 50 to 300 miles Inertial upper stage. A two- circle the globe in a waiting above Earth’s surface. It expe- Eccentric orbit. An extremely stage solid-rocket motor used posture, and then transfer pay- riences dramatically increased elongated elliptical orbit. to propel heavy satellites into load to a final, higher orbit. levels of heat compared to the mission orbit. lower layers. Ecliptic plane. The plane Payload. Any spacecraft’s defined by the circle on the ce- Ionosphere. A region of elec- crew or cargo; the mission Transfer. Any maneuver that lestial sphere traced by the path trically charged thin air layers element supported by the changes a spacecraft orbit. of the sun. that begins about 30 miles spacecraft. A radar or radio above Earth’s atmosphere. Transponder. Elliptical orbit. Any non circular, Perigee. The point of minimum set that, upon receiving a des- closed spaceflight path. Low Earth orbit (LEO). Flight altitude above Earth (or the ignated signal, emits a radio Exosphere. The upper limits path between Earth’s atmo- moon, a planet, etc.) main- signal of its own. sphere and the bottom of the of Earth’s atmosphere, ranging tained by a body in elliptical The region of Van Allen belts, i.e., from about Troposphere. from about 300 miles altitude to orbit. the atmosphere from Earth’s 60 to 300 miles altitude. about 2,000 miles altitude. Period. The amount of time surface to about 10 miles Expendable launch vehicle a spacecraft requires to go above the equator and five (ELV). A launch vehicle that through one complete orbit. miles above the poles. This is cannot be reused after one where most clouds, wind, rain, flight. and other weather occurs. Van Allen belts. Zones of intense radiation trapped in Earth’s magnetosphere that could damage unshielded spacecraft. 20 AIR FORCE Magazine / August 1997 May 24 Atlas D/Agena A performs first spacebased de- July 20 Apollo 11 puts first booster places MIDAS II, first tection of a nuclear explosion. human, Neil A. Armstrong, on Space Firsts early warning satellite, in orbit. the moon. July 28, 1964 First close-up June 22 US performs first lunar pictures provided by November 14–24 US Apollo February 24, 1949 Project successful launch of multiple Ranger 7 spacecraft. 12 mission deploys first major Bumper, the first fully success- independently instrumented scientific experiments on the First Atlas/Agena ful two-stage rocket-launch satellites by a single rocket. August 14 moon and completes first into space, reaches a record D standard launch vehicle suc- acquisition of samples from an altitude of 244 miles. August 11 Capsule ejected cessfully fired from Vanden- earlier spacecraft—Surveyor 3. from Discoverer 13 parachutes berg AFB. July 24, 1950 Bumper-WAC into Pacific Ocean and be- February 11, 1970 Japan First space- becomes first missile launched comes first orbital payload ever March 18, 1965 launches first satellite, Osumi, walk conducted by Alexei from Cape Canaveral, Fla. recovered. from Kagoshima Space Center Leonov of Soviet Voskhod 2. using Lambda 4S solid-fuel September 20, 1956 US Ju- August 12 First passive com- Gemini 3 astronauts rocket. piter C rocket achieves record munications carried via Echo 1 March 23 Maj. Virgil I. “Gus” Grissom first flight, reaching an altitude satellite. January 31, 1971 Apollo 14 of 682 miles and landing 3,400 and Lt. Cmdr. John W. Young launched; its astronauts will miles from Cape Canaveral. August 19 Capsule containing complete world’s first piloted complete first manned landing first satellite photographs of orbital maneuver. on lunar highlands. August 21, 1957 First suc- Soviet Union ejected from Dis- Gemini 4 astronaut cessful launch of Soviet R7 coverer 14 becomes first orbital June 4 April 19 First space station, Maj. Edward H. White performs rocket, which six weeks later payload recovered in midair by Salyut 1, goes aloft. first American spacewalk. will loft Sputnik into orbit. C-119 Flying Boxcar. June 6 USSR’s Soyuz 11 per- July 14 Mariner provides the October 4 USSR launches January 31, 1961 Preparing forms first successful docking first close-up pictures of Mars. Sputnik 1, the first man-made for manned spaceflight, US with Salyut space station. satellite, into Earth orbit. launches a Mercury capsule August 21 Gemini 5 launched First British satel- carrying the chimpanzee Ham October 28 November 3 First animal in as first manned spacecraft lite, Prospero, launched into on a suborbital trajectory. orbit, a dog, is carried aloft by using fuel cells for electrical orbit on Black Arrow rocket. power rather than batteries.