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OPS 9794
OPS 9794, also known as Navstar 8, GPS I-8 and GPS SVN-8, was an American navigation satellite launched in 1983 as part of the Global Positioning System development program. It was the eighth of eleven Block I GPS satellites to be launched. Background Global Positioning System (GPS) was developed by the U.S. Department of Defense to provide all-weather round-the-clock navigation capabilities for military ground, sea, and air forces. Since its implementation, GPS has also become an integral asset in numerous civilian applications and industries around the globe, including recreational used (e.g., boating, aircraft, hiking), corporate vehicle fleet tracking, and surveying. GPS employs 24 spacecraft in 20,200 km circular orbits inclined at 55°. These vehicles are placed in 6 orbit planes with four operational satellites in each plane. Spacecraft The first eleven spacecraft (GPS Block 1) were used to demonstrate the feasibility of the GPS system. They were 3-axis stabil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Navigation Satellite
A satellite navigation or satnav system is a system that uses satellites to provide autonomous geopositioning. A satellite navigation system with global coverage is termed global navigation satellite system (GNSS). , four global systems are operational: the United States's Global Positioning System (GPS), Russia's Global Navigation Satellite System (GLONASS), China's BeiDou Navigation Satellite System (BDS), and the European Union's Galileo. Two regional systems are operational: India's NavIC and Japan's QZSS. '' Satellite-based augmentation systems'' (SBAS), designed to enhance the accuracy of GNSS, include Japan's Quasi-Zenith Satellite System (QZSS), India's GAGAN and the European EGNOS, all of them based on GPS. Previous iterations of the BeiDou navigation system and the present Indian Regional Navigation Satellite System (IRNSS), operationally known as NavIC, are examples of stand-alone operating regional navigation satellite systems (RNSS). Satellite navigation dev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Department Of Defense
The United States Department of Defense (DoD, USDOD, or DOD) is an United States federal executive departments, executive department of the federal government of the United States, U.S. federal government charged with coordinating and supervising the six U.S. armed services: the United States Army, Army, United States Navy, Navy, United States Marine Corps, Marines, United States Air Force, Air Force, United States Space Force, Space Force, the United States Coast Guard, Coast Guard for some purposes, and related functions and agencies. As of November 2022, the department has over 1.4 million active-duty uniformed personnel in the six armed services. It also supervises over 778,000 National Guard (United States), National Guard and reservist personnel, and over 747,000 civilians, bringing the total to over 2.91 million employees. Headquartered at the Pentagon in Arlington County, Virginia, just outside Washington, D.C., the Department of Defense's stated mission is "to provid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Period
The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets, exoplanets orbiting other stars, or binary stars. It may also refer to the time it takes a satellite orbiting a planet or moon to complete one orbit. For celestial objects in general, the orbital period is determined by a 360° revolution of one body around its primary, ''e.g.'' Earth around the Sun. Periods in astronomy are expressed in units of time, usually hours, days, or years. Its reciprocal is the orbital frequency, a kind of revolution frequency, in units of hertz. Small body orbiting a central body According to Kepler's Third Law, the orbital period ''T'' of two point masses orbiting each other in a circular or elliptic orbit is: :T = 2\pi\sqrt where: * ''a'' is the orbit's semi-major axis * ''G'' is the gravitationa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apsis
An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides pertaining to orbits around different bodies have distinct names to differentiate themselves from other apsides. Apsides pertaining to geocentric orbits, orbits around the Earth, are at the farthest point called the ''apogee'', and at the nearest point the ''perigee'', like with orbits of satellites and the Moon around Earth. Apsides pertaining to orbits around the Sun are named ''aphelion'' for the farthest and ''perihelion'' for the nearest point in a heliocentric orbit. Earth's two apsides are the farthest point, ''aphelion'', and the nearest point, ''perihelion'', of its orbit around the host Sun. The terms ''aphelion'' and ''perihelion'' apply in the same way to the orbits of Jupiter and the other planets, the comets, and the asteroids of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apogee Kick Motor
An apogee kick motor (AKM) is a rocket motor that is regularly employed on artificial satellites to provide the final impulse to change the trajectory from the transfer orbit into its final orbit (most commonly circular). For a satellite launched from the Earth, the rocket firing is done at the highest point of the transfer orbit, known as the apogee. An apogee kick motor is used, for example, for satellites launched into a geostationary orbit. As the vast majority of geostationary satellite launches are carried out from spaceports at a significant distance away from Earth's equator, the carrier rocket often only launches the satellite into an orbit with a non-zero inclination approximately equal to the latitude of the launch site. This orbit is commonly known as a "geostationary transfer orbit" or a "geosynchronous transfer orbit". The satellite must then provide thrust to bring forth the needed delta v to reach a geostationary orbit. This is typically done with a fixed onbo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star (rocket Stage)
The Star is a family of US solid-propellant rocket motors originally developed by Thiokol and used by many space propulsion and launch vehicle stages. They are used almost exclusively as an upper stage, often as an apogee kick motor. The number designations refer to the approximate diameter of the fuel casing in inches. Three Star 37 stages, and one Star 48 stage, were launched on solar escape trajectories; fast enough to leave the Sun's orbit and out into interstellar space, where barring the low chance of colliding with debris, they will travel past other stars in the Milky Way galaxy and survive potentially intact for millions of years. Star 13 The Star 13 (TE-M-458) is a solid fuel apogee kick motor. It was used on NASA's Anchored Interplanetary Monitoring Platform satellites. Several other versions were developed. Star 13D (TE-M-375) was used on the Syncom 1, Star 13A (TE-M-516) on LES 1/ 2, Aurora (P67-1), Orbiscal (P68-1), Lincoln Calibration Sphere 4, S3-2, Sol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medium Earth Orbit
A medium Earth orbit (MEO) is an geocentric orbit, Earth-centered orbit with an altitude above a low Earth orbit (LEO) and below a high Earth orbit (HEO) – between above sea level.''Catalog of Earth Satellite Orbits'' NASA Earth Observatory. 4 September 2009. Accessed 2 May 2021. The boundary between MEO and LEO is an arbitrary altitude chosen by accepted convention, whereas the boundary between MEO and HEO is the particular altitude of a geosynchronous orbit, in which a satellite takes 24 hours to circle the Earth, the same period as the Earth’s own rotation. All satellites in MEO have an orbital period of less than 24 hours, with the minimum period (for a circular orbit at the lowest MEO altitude) about 2 hours. Satellites in MEO or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multistage Rocket
A multistage rocket or step rocket is a launch vehicle that uses two or more rocket ''stages'', each of which contains its own engines and propellant. A ''tandem'' or ''serial'' stage is mounted on top of another stage; a ''parallel'' stage is attached alongside another stage. The result is effectively two or more rockets stacked on top of or attached next to each other. Two-stage rockets are quite common, but rockets with as many as five separate stages have been successfully launched. By jettisoning stages when they run out of propellant, the mass of the remaining rocket is decreased. Each successive stage can also be optimized for its specific operating conditions, such as decreased atmospheric pressure at higher altitudes. This ''staging'' allows the thrust of the remaining stages to more easily accelerate the rocket to its final velocity and height. In serial or tandem staging schemes, the first stage is at the bottom and is usually the largest, the second stage and subse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Launch Vehicle
A launch vehicle is typically a rocket-powered vehicle designed to carry a payload (a crewed spacecraft or satellites) from Earth's surface or lower atmosphere to outer space. The most common form is the ballistic missile-shaped multistage rocket, but the term is more general and also encompasses vehicles like the Space Shuttle. Most launch vehicles operate from a launch pad, supported by a missile launch control center, launch control center and systems such as vehicle assembly and fueling. Launch vehicles are engineered with advanced aerodynamics and technologies, which contribute to high operating costs. An orbital spaceflight, orbital launch vehicle must lift its payload at least to the boundary of space, approximately and accelerate it to a horizontal velocity of at least . Suborbital spaceflight, Suborbital vehicles launch their payloads to lower velocity or are launched at elevation angles greater than horizontal. Practical orbital launch vehicles use chemical prope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SM-65E Atlas
The SM-65E Atlas, or Atlas-E, was an operational variant of the Atlas missile. It first flew on October 11, 1960, and was deployed as an operational ICBM from September 1961 until April 1966. Following retirement as an ICBM, the Atlas-E, along with the Atlas-F, was refurbished for orbital launches as the Atlas E/F. The last Atlas E/F launch was conducted on March 24, 1995, using a rocket which had originally been built as an Atlas E. As fully operational ICBMs, the Atlas E and F, which differed only in guidance systems, had upgraded engines and inertial control instead of the Atlas D's radio ground guidance. The ignition system was also different from the one used on the D-series, which used a "wet" start, meaning that the propellants were injected into the combustion chamber prior to ignition, and a hypergolic igniter on the fully developed version. The Atlas E/F for comparison used pyrotechnic cartridges and a dry start (ignition coming before propellant injection) for an ext ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Panels On Spacecraft
Spacecraft operating in the inner Solar System usually rely on the use of power electronics-managed photovoltaic solar panels to derive electricity from sunlight. Outside the orbit of Jupiter, solar radiation is too weak to produce sufficient power within current solar technology and spacecraft mass limitations, so radioisotope thermoelectric generators (RTGs) are instead used as a power source.NASA JPL Publication: Basics of Space Flight, Chapter 11. Typical Onboard Systems, Electrical Power Supply and Distribution Subsystems, History The first practical silicon-based solar cells were introduced by Russell Shoemaker Ohl, a researcher at Bell Labs in 1940. It was only 1% efficient. In April 25, 1954 in Murray Hill, New Jersey. They demonstrated their solar panel by using it to power a small toy Ferris wheel and a solar powered radio transmitter. They were initially about 6% efficient, but improvements began to raise this number almost immediately. Bell had been interested in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultra High Frequency
Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter (one decimetre). Radio waves with frequencies above the UHF band fall into the super-high frequency (SHF) or microwave frequency range. Lower frequency signals fall into the VHF ( very high frequency) or lower bands. UHF radio waves propagate mainly by line of sight; they are blocked by hills and large buildings although the transmission through building walls is strong enough for indoor reception. They are used for television broadcasting, cell phones, satellite communication including GPS, personal radio services including Wi-Fi and Bluetooth, walkie-talkies, cordless phones, satellite phones, and numerous other applications. The IEEE defines the UHF radar band as frequencies between 300 MHz and 1 GHz. Two other IEEE ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
