The Orbiting Solar Observatory (abbreviated OSO) 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 (OSO 1–7) were built by Ball Aerospace, then known as Ball Brothers Research Corporation (BBRC), in Boulder, Colorado. [1] OSO 8 was built by Hughes Space and Communications Company, in Culver City, California.
The basic design of the entire series featured a rotating section, the "Wheel", to provide gyroscopic stability. A second section, the "Sail", was driven electrically against the Wheel's rotation, and stabilized to point at the Sun. The Sail carried pointed solar instruments, and also the array of solar photovoltaic cells which powered the spacecraft. The critical bearing between the Wheel and the Sail was a major feature of the design, as it had to operate smoothly for months in the hard vacuum of space without normal lubrication. It also carried both the power from the Sail and the data from the pointed solar instruments to the Wheel, where most of the spacecraft functions were located. Additional science instruments could also be located in the Wheel, generally looking out on a rotating radius vector which scanned the sky, and also across the Sun, every few seconds.
OSO B suffered an incident during integration and checkout activities on 14 April 1964. The satellite was inside the Spin Test Facility at Cape Canaveral attached to the third stage of its Delta C booster when a technician accidentally ignited the booster through static electricity. The third-stage motor activated, launched itself and the satellite into the roof, and ricocheted into a corner of the facility until burning out. Three technicians were burned to death. The satellite, although damaged, was able to be repaired using a combination of prototype parts, spare flight parts and new components. It was launched ten months later on 3 February 1965 and was designated OSO 2 on orbit. [2]
OSO C never made it to orbit. Liftoff took place on 25 August 1965 and all went well through the second stage burn. During the coasting phase prior to third stage separation, its rocket motor ignited prematurely. This registered on ground readouts as an attitude disturbance followed by loss of second stage telemetry, and although the third stage managed to separate itself, it suffered from an 18% drop in thrust. The OSO spacecraft could not attain orbital velocity and instead fell back into the atmosphere and burned up. The failure was suspected to have been caused by a modification to the igniter mechanism in the third stage after some minor technical difficulties experienced on the previous Delta C launch (TIROS 10 on 2 Jul). [3]
Designation | Launch Date | Re-entry date | Notable results |
---|---|---|---|
OSO 1 (OSO A) | 7 March 1962 | 7 October 1981 [4] | |
OSO 2 (OSO B2) | 3 February 1965 | 8 August 1989 [5] | |
OSO 3 (OSO E1) | 8 March 1967 | 4 April 1982 [6] | Observed solar flares from the Sun, as well as a flare from Scorpius X-1 [7] [8] |
OSO 4 (OSO D) | 18 October 1967 | 14 June 1982 [9] | |
OSO 5 (OSO F) | 22 January 1969 | 2 April 1984 [10] | Measured diffuse background X-ray radiation from 14-200 keV [11] [12] |
OSO 6 (OSO G) | 9 August 1969 | 7 March 1981 [13] | Observed three instances of hard X-ray coincidences with gamma ray bursts. [14] |
OSO 7 (OSO H) | 29 September 1971 | 8 July 1974 [15] | Observed solar flares in the gamma ray spectrum. Collected data allowed for identification of Vela X-1 as a High-mass X-ray binary. [16] [17] |
OSO 8 (OSO I) | 21 June 1975 | 8 July 1986 [18] | Found an iron emission line in the X-ray spectrum of a galaxy cluster. [19] |
The Advanced Orbiting Solar Observatory (AOSO) program was developed in the mid 1960s as a more advanced version of the OSO series. Conceived as a polar-orbiting satellite system, these spacecraft would continuously monitor the Sun and surrounding environment with detectors and electronic imaging ranging from x-rays to visual light. Due to budget constraints, the AOSO program was cancelled in 1965. Instead, it was replaced by the OSO-I, OSO-J and OSO-K satellites. Only OSO-I, which became OSO 8, was ever launched. [20]
Another satellite using the Orbiting Solar Observatory platform was developed and launched: the Solwind satellite. It was launched February 24, 1979. It was operated by the DoD Space Test Program. It was destroyed September 13, 1985 on an ASAT missile test.
Interplanetary spaceflight or interplanetary travel is the crewed or uncrewed travel between stars and planets, usually within a single planetary system. In practice, spaceflights of this type are confined to travel between the planets of the Solar System. Uncrewed space probes have flown to all the observed planets in the Solar System as well as to dwarf planets Pluto and Ceres, and several asteroids. Orbiters and landers return more information than fly-by missions. Crewed flights have landed on the Moon and have been planned, from time to time, for Mars, Venus and Mercury. While many scientists appreciate the knowledge value that uncrewed flights provide, the value of crewed missions is more controversial. Science fiction writers propose a number of benefits, including the mining of asteroids, access to solar power, and room for colonization in the event of an Earth catastrophe.
Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. In-space propulsion exclusively deals with propulsion systems used in the vacuum of space and should not be confused with space launch or atmospheric entry.
Solar sails are a method of spacecraft propulsion using radiation pressure exerted by sunlight on large surfaces. A number of spaceflight missions to test solar propulsion and navigation have been proposed since the 1980s. The first spacecraft to make use of the technology was IKAROS, launched in 2010.
Spaceflight is an application of astronautics to fly objects, usually spacecraft, into or through outer space, either with or without humans on board. Most spaceflight is uncrewed and conducted mainly with spacecraft such as satellites in orbit around Earth, but also includes space probes for flights beyond Earth orbit. Such spaceflights operate either by telerobotic or autonomous control. The first spaceflights began in the 1950s with the launches of the Soviet Sputnik satellites and American Explorer and Vanguard missions. Human spaceflight programs include the Soyuz, Shenzhou, the past Apollo Moon landing and the Space Shuttle programs. Other current spaceflight are conducted to the International Space Station and to China's Tiangong Space Station.
A trans-lunar injection (TLI) is a propulsive maneuver, which is used to send a spacecraft to the Moon. Typical lunar transfer trajectories approximate Hohmann transfers, although low-energy transfers have also been used in some cases, as with the Hiten probe. For short duration missions without significant perturbations from sources outside the Earth-Moon system, a fast Hohmann transfer is typically more practical.
A gravity assist, gravity assist maneuver, swing-by, or generally a gravitational slingshot in orbital mechanics, is a type of spaceflight flyby which makes use of the relative movement and gravity of a planet or other astronomical object to alter the path and speed of a spacecraft, typically to save propellant and reduce expense.
Orbital Sciences Corporation was an American company specializing in the design, manufacture, and launch of small- and medium- class space and launch vehicle systems for commercial, military and other government customers. In 2014, Orbital merged with Alliant Techsystems (ATK) to create a new company called Orbital ATK, which in turn was purchased by Northrop Grumman in 2018.
Orbiting Geophysical Observatory (OGO) Program of NASA refers to the six satellites launched by the United States that were in use from September 1964 to 1972, designed to study the Earth's magnetosphere. The satellites successfully studied the interactions between the Earth and the Sun, despite a number of technical problems. Each satellite had 20 to 25 instruments. The project manager for all 6 OGO projects was Wilfred Scull.
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Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission began in February 2007 as a constellation of five NASA satellites to study energy releases from Earth's magnetosphere known as substorms, magnetic phenomena that intensify auroras near Earth's poles. The name of the mission is an acronym alluding to the Titan Themis.
The following outline is provided as an overview of and topical guide to space exploration.
The Star 48 is the largest of a family of solid rocket motors used by many space propulsion and launch vehicle stages, almost exclusively as an upper stage. It was developed primarily by Thiokol Propulsion and after several mergers, is manufactured by Northrop Grumman’s Space Systems division. A Star 48B stage is also one of the few man-made items sent on escape trajectories out of the Solar System, although it is derelict since its use. The Star 48B variant was the PAM-D upper stage used on the retired Delta II rocket.
Gamma was a Soviet gamma ray telescope. It was launched on 11 July 1990 into an orbit around Earth with a height of 375 km and an inclination of 51.6 degrees. It lasted for around 2 years. On board the mission were three telescopes, all of which could be pointed at the same source. The project was a joint Soviet-French project.
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.
OSO 3, or Third Orbiting Solar Observatory was launched on March 8, 1967, into a nearly circular orbit of mean altitude 550 km, inclined at 33° to the equatorial plane. Its on-board tape recorder failed on June 28, 1968, allowing only the acquisition of sparse real-time data during station passes thereafter; the last data were received on November 10, 1969. OSO 3 reentered the Earth's atmosphere and burned up on April 4, 1982.
TD-1A, or Thor-Delta 1A, was a European astrophysical research satellite which was launched in 1972. Operated by the European Space Research Organisation, TD-1A made astronomical surveys primarily in the ultraviolet, but also using x-ray and gamma ray detectors.
The Near-Earth Asteroid Scout was a mission by NASA to develop a controllable low-cost CubeSat solar sail spacecraft capable of encountering near-Earth asteroids (NEA). NEA Scout was one of ten CubeSats launched into a heliocentric orbit on Artemis 1, the maiden flight of the Space Launch System, on 16 November 2022.