Anti-satellite weapons (ASAT) are space weapons designed to incapacitate or destroy satellites for strategic or tactical purposes. Although no ASAT system has yet been utilised in warfare, a few countries have successfully shot down their own satellites to demonstrate their ASAT capabilities in a show of force. ASATs have also been used to remove decommissioned satellites.
Space debris are defunct human-made objects in space – principally in Earth orbit – which no longer serve a useful function. These include derelict spacecraft – nonfunctional spacecraft and abandoned launch vehicle stages – mission-related debris, and particularly numerous in Earth orbit, fragmentation debris from the breakup of derelict rocket bodies and spacecraft. In addition to derelict human-made objects left in orbit, other examples of space debris include fragments from their disintegration, erosion and collisions or even paint flecks, solidified liquids expelled from spacecraft, and unburned particles from solid rocket motors. Space debris represents a risk to spacecraft.
A sungrazing comet is a comet that passes extremely close to the Sun at perihelion – sometimes within a few thousand kilometres of the Sun's surface. Although small sungrazers can completely evaporate during such a close approach to the Sun, larger sungrazers can survive many perihelion passages. However, the strong evaporation and tidal forces they experience often lead to their fragmentation.
Space warfare is hypothetical combat in which one or more belligerents are situated in outer space. The scope of space warfare therefore includes ground-to-space warfare, such as attacking satellites from the Earth; space-to-space warfare, such as satellites attacking satellites; and space-to-ground warfare, such as satellites attacking Earth-based targets. Space warfare in fiction is thus sub-genre and theme of science fiction, where it is portrayed with a range of realism and plausibility.
The Solar Maximum Mission satellite was designed to investigate Solar phenomena, particularly solar flares. It was launched on February 14, 1980. The SMM was the first satellite based on the Multimission Modular Spacecraft bus manufactured by Fairchild Industries, a platform which was later used for Landsats 4 and 5 as well as the Upper Atmosphere Research Satellite.
The Solar Orbiter (SO) is a Sun-observing probe developed by the European Space Agency (ESA) with a National Aeronautics and Space Administration (NASA) contribution. Solar Orbiter, designed to obtain detailed measurements of the inner heliosphere and the nascent solar wind, will also perform close observations of the polar regions of the Sun which is difficult to do from Earth. These observations are important in investigating how the Sun creates and controls its heliosphere.
The Kessler syndrome, proposed by NASA scientist Donald J. Kessler in 1978, is a scenario in which the density of objects in low Earth orbit (LEO) due to space pollution is numerous enough that collisions between objects could cause a cascade in which each collision generates space debris that increases the likelihood of further collisions. In 2009 Kessler wrote that modeling results had concluded that the debris environment was already unstable, "such that any attempt to achieve a growth-free small debris environment by eliminating sources of past debris will likely fail because fragments from future collisions will be generated faster than atmospheric drag will remove them". One implication is that the distribution of debris in orbit could render space activities and the use of satellites in specific orbital ranges difficult for many generations.
Fēngyún are China's meteorological satellites. Launched since 1988 into polar sun-synchronous and geosynchronous orbit, each three-axis stabilized Fengyun satellite is built by the Shanghai Academy of Spaceflight Technology (SAST) and operated by the China Meteorological Administration (CMA). To date, China has launched twenty-one Fengyun satellites in four classes. Fengyun 1 and Fengyun 3 satellites are in polar, sun-synchronous orbit and Low Earth orbit while Fengyun 2 and 4 are geosynchronous orbit.
The Orbiting Solar Observatory Program was the name of a series of American space telescopes primarily intended to study the Sun, though they also included important non-solar experiments. Eight were launched successfully into low Earth orbit by NASA between 1962 and 1975 using Delta rockets. Their primary mission was to observe an 11-year sun spot cycle in UV and X-ray spectra. The initial seven were built by Ball Aerospace, then known as Ball Brothers Research Corporation (BBRC), in Boulder, Colorado. OSO 8 was built by Hughes Space and Communications Company, in Culver City, California.
The ASM-135 ASAT is an air-launched anti-satellite multistage missile that was developed by Ling-Temco-Vought's LTV Aerospace division. The ASM-135 was carried exclusively by United States Air Force (USAF) F-15 Eagle fighter aircraft.
On 11 January 2007, China conducted an anti-satellite missile test. A Chinese weather satellite—the FY-1C polar orbit satellite of the Fengyun series, at an altitude of 865 kilometres (537 mi), with a mass of 750 kilograms (1,650 lb)—was destroyed by a kinetic kill vehicle traveling with a speed of 8 km/s (18,000 mph) in the opposite direction. It was launched with a multistage solid-fuel missile from Xichang Satellite Launch Center or nearby.
USA-193, also known as NRO Launch 21, was a United States military reconnaissance satellite launched on 14 December 2006. It was the first launch conducted by the United Launch Alliance (ULA). Owned by the National Reconnaissance Office (NRO), the craft's precise function and purpose were classified. On 21 February 2008, it was destroyed as a result of Operation Burnt Frost.
Strictly speaking, a satellite collision is when two satellites collide while in orbit around a third, much larger body, such as a planet or moon. This definition can be loosely extended to include collisions between sub-orbital or escape-velocity objects with an object in orbit. Prime examples are the anti-satellite weapon tests.
OSO 7 or Orbiting Solar Observatory 7, before launch known as OSO H is the seventh in the series of American Orbiting Solar Observatory satellites launched by NASA between 1962 and 1975. OSO 7 was launched from Cape Kennedy on 29 September 1971 by a Delta N rocket into a 33.1° inclination, low-Earth orbit, and re-entered the Earth's atmosphere on 9 July 1974. It was built by the Ball Brothers Research Corporation (BBRC), now known as Ball Aerospace, in Boulder Colorado.
Operation Burnt Frost was a military operation to intercept and destroy non-functioning U.S. National Reconnaissance Office (NRO) satellite USA-193. The mission was described by the Missile Defense Agency as a "mission of safeguarding human life against the uncontrolled re-entry of a 5,000-pound satellite containing over 1,000 pounds of hazardous hydrazine propellant". The launch occurred on 20 February 2008 at approximately 10:26 p.m. EST from the USS Lake Erie, using a heavily modified Standard Missile-3 (SM-3) to shoot down the satellite. A few minutes after launch, the SM-3 intercepted its target and successfully completed its mission. The operation received scrutiny from other countries, mainly China and Russia.
Mars 1M No.1, designated Mars 1960A by NASA analysts and dubbed Marsnik 1 by the Western media, was the first spacecraft launched as part of the Soviet Union's Mars programme. A Mars 1M spacecraft, it was intended for conducting flight testing system and to study the interplanetary environment between Earth and Mars, however it was lost in a launch failure before it could begin its mission.
Student Nitric Oxide Explorer, was a NASA small scientific satellite which studied the concentration of nitric oxide in the thermosphere. It was launched in 1998 as part of NASA's Explorer program. The satellite was the first of three missions developed within the Student Explorer Demonstration Initiative (STEDI) program funded by the NASA and managed by the Universities Space Research Association (USRA). STEDI was a pilot program to demonstrate that high-quality space science can be carried out with small, low-cost free-flying satellites on a time scale of two years from go-ahead to launch. The satellite was developed by the University of Colorado Boulder's Laboratory for Atmospheric and Space Physics (LASP) and had met its goals by the time its mission ended with reentry in December 2003.
Microsat-R was claimed to be an experimental imaging satellite manufactured by DRDO and launched by Indian Space Research Organisation on 24 January 2019 for military use. The satellite served as a target for an anti-satellite test on 27 March, 2019.
On 27 March 2019, India tested an anti-satellite weapon (ASAT) during an operation code named Mission Shakti. The target of the test was a satellite present in a low Earth orbit, which was hit with a kinetic kill vehicle.
Kosmos-1408 was an electronic signals intelligence (ELINT) satellite operated by the Soviet Union. It was launched into low Earth orbit on 16 September 1982 at 14:55 UTC, replacing Kosmos-1378. It operated for around two years before becoming inactive and left in orbit.
