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Navstar 7
Navstar 7, also known as GPS I-7 and GPS SVN-7, was an American navigation satellite which was lost in a launch failure in 1981. It was intended to be used in the Global Positioning System development program. It was the seventh of eleven Block I GPS satellites to be launched, and the only one to fail to achieve orbit. 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 ... [...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] |
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] |
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] |
Range Safety
In rocketry, range safety or flight safety is ensured by monitoring the flight paths of missiles and launch vehicles, and enforcing strict guidelines for rocket construction and ground-based operations. Various measures are implemented to protect nearby people, buildings and infrastructure from the dangers of a rocket launch. Governments maintain many regulations on launch vehicles and associated ground systems, prescribing the procedures that need to be followed by any entity aiming to launch into space. Areas in which one or more spaceports are operated, or ranges, issue out closely guarded exclusion zones for air and sea traffic prior to launch, and close off certain areas to the public. Contingency procedures are performed if a vehicle malfunctions or veers off course mid-flight. Sometimes, a range safety officer (RSO) commands the flight or mission to end by sending a signal to the flight termination system (FTS) aboard the rocket. This takes measures to eliminate any mean ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MA-5 (rocket Stage)
MA-5 was an American liquid fueled rocket stage, developed by Lockheed Martin for use on the Atlas I rocket. Design MA-5 functioned as the "half stage" in the Atlas's "stage-and-a-half" design, meaning they functioned as a booster attached to a central sustainer core, but did not include their own fuel tanks. Instead, fuel was drained out of the tanks of the sustainer core, until partway through the launch the booster segment was jettisoned. Similar to the booster segments on previous Atlas rockets, MA-5 consisted of a thrust structure with attachment points and fuel lines for two LR-89-7 rocket engines, each contained in a nacelle for aerodynamic reasons. The middle was left empty to accommodate the LR-105-7 engine of the sustainer stage. The two booster engines shared a common gas generator, but separate turbopump A turbopump is a fluid pump with two main components: a rotodynamic pump and a driving gas turbine, usually both mounted on the same shaft, or sometimes gear ... [...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] |
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] |
Telemetry
Telemetry is the in situ collection of measurements or other data at remote points and their automatic transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Greek roots ''tele'', 'far off', and ''metron'', 'measure'. Systems that need external instructions and data to operate require the counterpart of telemetry: telecommand. Although the term commonly refers to wireless data transfer mechanisms (e.g., using radio, ultrasonic, or infrared systems), it also encompasses data transferred over other media such as a telephone or computer network, optical link or other wired communications like power line carriers. Many modern telemetry systems take advantage of the low cost and ubiquity of GSM networks by using SMS to receive and transmit telemetry data. A ''telemeter'' is a physical device used in telemetry. It consists of a sensor, a transmission path, and a display, recording, or control device. Electronic devices are widely u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S Band
The S band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a part of the microwave band of the electromagnetic spectrum covering frequencies from 2 to 4 gigahertz (GHz). Thus it crosses the conventional boundary between the UHF and SHF bands at 3.0 GHz. The S band is used by airport surveillance radar for air traffic control, weather radar, surface ship radar, and some communications satellites, particularly satellites used by NASA to communicate with the Space Shuttle and the International Space Station. The 10 cm radar short-band ranges roughly from 1.55 to 5.2 GHz. India's regional satellite navigation network ( IRNSS) broadcasts on 2.483778 to 2.500278 GHz. The S band also contains the 2.4–2.483 GHz ISM band, widely used for low power unlicensed microwave devices such as cordless phones, wireless headphones (Bluetooth), garage door openers, keyless vehicle locks, baby monitors as well as for medical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reaction Wheel
A reaction wheel (RW) is an electric motor attached to a flywheel, which, when its rotation speed is changed, causes a counter-rotation proportionately through conservation of angular momentum. A reaction wheel can rotate only around its center of mass; it is not capable of moving from one place to another ( translational force). Reaction wheels are used primarily by spacecraft for three-axis attitude control, and do not require rockets or external applicators of torque, which reduces the mass fraction needed for fuel. They provide a high pointing accuracy, and are particularly useful when the spacecraft must be rotated by very small amounts, such as keeping a telescope pointed at a star. A reaction wheel is sometimes operated at a constant (or near-constant) rotation speed, to provide a satellite with a large amount of stored angular momentum. Doing so alters the spacecraft's rotational dynamics so that disturbance torques perpendicular to one axis of the satellite (the axis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
