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Explorer S-1 (satellite)
Explorer S-1, also known as NASA S-1 or Explorer 7X, was a NASA Earth science satellite equipped with a suite of scientific instruments to study the environment around the Earth. The spacecraft and its Juno II launch vehicle were destroyed five seconds after launch on 16 July 1959, in a spectacular launch failure caused by complications with the launch vehicle's power supply. A relaunch of the mission in October 1959, Explorer 7 (S-1A), was successful. Mission The mission was planned to be the sixth flight of the Explorer program, designated NASA S-1 and Explorer 7X retrospectively. The objectives of the mission were to measure the Earth's radiation balance, and the abundance of Lyman-alpha X-rays and cosmic rays, including heavy primary cosmic rays. The spacecraft was also designed as a test bed for satellite capabilities, being equipped with instruments to measure the spacecraft's temperature, micrometeorite impacts and the erosion of solar cells exposed to the vacuum of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Range Safety Officer
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] |
Lyman-alpha
Lyman-alpha, typically denoted by Ly-α or Lyα, is a spectral line of hydrogen (or, more generally, of any one-electron atom) in the Lyman series. It is emitted when the atomic electron transitions from an ''n'' = 2 orbital to the ground state (''n'' = 1), where ''n'' is the principal quantum number. In hydrogen, its wavelength of 1215.67 angstroms ( or ), corresponding to a frequency of about , places Lyman-alpha in the ultraviolet (UV) part of the electromagnetic spectrum. More specifically, Ly-α lies in vacuum UV (VUV), characterized by a strong absorption in the air. Fine structure The Lyman-alpha doublet. Because of the spin–orbit interaction, the Lyman-alpha line splits into a fine-structure doublet with the wavelengths of 1215.668 and 1215.674 angstroms. These components are called Ly-α3/2 and Ly-α1/2, respectively. The eigenstates of the perturbed Hamiltonian are labeled by the ''total'' angular momentum ''j'' of the electron, not just the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interplanetary Medium
The interplanetary medium (IPM) or interplanetary space consists of the mass and energy which fills the Solar System, and through which all the larger Solar System bodies, such as planets, dwarf planet A dwarf planet is a small planetary-mass object that is in direct orbit around the Sun, massive enough to be hydrostatic equilibrium, gravitationally rounded, but insufficient to achieve clearing the neighbourhood, orbital dominance like the ...s, asteroids, and comets, move. The IPM stops at the Heliopause (astronomy), heliopause, outside of which the interstellar medium begins. Before 1950, interplanetary space was widely considered to either be an empty vacuum, or consisting of "Aether theories, aether". Composition and physical characteristics The interplanetary medium includes Interplanetary dust cloud, interplanetary dust, cosmic rays, and hot Plasma (physics), plasma from the solar wind. The density of the interplanetary medium is very low, decreasing in inverse pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heliocentric Orbit
A heliocentric orbit (also called circumsolar orbit) is an orbit around the barycenter of the Solar System, which is usually located within or very near the surface of the Sun. All planets, comets, and asteroids in the Solar System, and the Sun itself are in such orbits, as are many artificial probes and pieces of debris. The moons of planets in the Solar System, by contrast, are not in heliocentric orbits, as they orbit their respective planet (although the Moon has a convex orbit around the Sun). The barycenter of the Solar System, while always very near the Sun, moves through space as time passes, depending on where other large bodies in the Solar System, such as Jupiter and other large gas planets, are located at that time. A similar phenomenon allows the detection of exoplanets by way of the radial-velocity method. The ''helio-'' prefix is derived from the Greek word "ἥλιος", meaning "Sun", and also Helios, the personification of the Sun in Greek mythology. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pioneer 3
Pioneer 3 was a spin-stabilized spacecraft launched at 05:45:12 GMT on 6 December 1958 by the U.S. Army Ballistic Missile Agency in conjunction with NASA, using a Juno II rocket. This spacecraft was intended as a lunar probe, but failed to go past the Moon and into a heliocentric orbit as planned. It did however reach an altitude of 102,360 km before falling back to Earth. The revised spacecraft objectives were to measure radiation in the outer Van Allen radiation belt using two Geiger-Müller tubes and to test the trigger mechanism for a lunar photographic experiment. Spacecraft design Pioneer 3 was a cone-shaped probe 58 cm high and 25 cm diameter at its base. The cone was composed of a thin fiberglass shell coated with a gold wash to make it electrically conducting and painted with black and white stripes to maintain the temperature between 10 and 50 °C. At the tip of the cone was a small probe which combined with the cone itself to act as an antenna. At th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conformal Coating
Conformal coating is a protective, breathable coating of thin polymeric film applied to printed circuit boards (PCBs). Conformal coatings are typically applied with 25–250 μm thickness on electronic circuitry to protect against moisture and other substances. Coatings can be applied in many ways, including brushing, spraying, dispensing, and dip coating. Many materials can be used as conformal coatings depending on manufacturer needs, such as acrylic, silicone, urethane, and parylene. Many circuit board assembly firms apply a layer of transparent conformal coating to assemblies as an alternative to potting. Conformal coatings are used to protect electronic components from possible environmental exposure; they allow moisture to escape but protect against contamination. More recently, conformal coatings are being used to reduce the formation of whiskers and to prevent current bleed between closely positioned components. Applications Precision analogue circuitry may su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gimbal
A gimbal is a pivoted support that permits rotation of an object about an axis. A set of three gimbals, one mounted on the other with orthogonal pivot axes, may be used to allow an object mounted on the innermost gimbal to remain independent of the rotation of its support (e.g. vertical in the first animation). For example, on a ship, the gyroscopes, shipboard compasses, stoves, and even drink holders typically use gimbals to keep them upright with respect to the horizon despite the ship's pitching and rolling. The gimbal suspension used for mounting compasses and the like is sometimes called a Cardan suspension after Italian mathematician and physicist Gerolamo Cardano (1501–1576) who described it in detail. However, Cardano did not invent the gimbal, nor did he claim to. The device has been known since antiquity, first described in the 3rd c. BC by Philo of Byzantium, although some modern authors support the view that it may not have a single identifiable inventor. His ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rocketdyne S-3D
The Rocketdyne S-3D (Air Force designation LR79) is an American liquid rocket engine produced by Rocketdyne (a division of North American Aviation) between 1956 and 1961. It was a gas generator, pump-fed engine, using a liquid oxygen ( LOX) and RP-1 (kerosene) propellant combination, capable of producing 134,908 pounds of thrust (600.1 kN) at sea level. The S-3 was based on the Redstone engine, and is part of the LR79 family, used on the PGM-19 Jupiter and PGM-17 Thor missiles, and on the Juno II rocket. A second stage with four S-3 engines was considered for the Saturn A-2 study. Its design was used later as the basis for the H-1 rocket engine of the Saturn I, and the Rolls-Royce RZ.2 of the Blue Streak. Specifications Rocketdyne S-3D: * First flight: 1957 * Vehicles: PGM-19 Jupiter The PGM-19 Jupiter was the first nuclear weapon, nuclear armed, medium-range ballistic missile (MRBM) of the United States Air Force (USAF). It was a liquid-propellant rocket using R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Short Circuit
A short circuit (sometimes abbreviated to short or s/c) is an electrical circuit that allows a current to travel along an unintended path with no or very low electrical impedance. This results in an excessive current flowing through the circuit. The opposite of a short circuit is an open circuit, which is an infinite resistance (or very high impedance) between two nodes. Definition A short circuit is an abnormal connection between two nodes of an electric circuit intended to be at different voltages. This results in an electric current limited only by the Thévenin equivalent resistance of the rest of the network which can cause circuit damage, overheating, fire or explosion. Although usually the result of a fault, there are cases where short circuits are caused intentionally, for example, for the purpose of voltage-sensing crowbar circuit protectors. In circuit analysis, a ''short circuit'' is defined as a connection between two nodes that forces them to be at the sam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spin-stabilized
In aerospace engineering, spin stabilization is a method of stabilizing a satellite or launch vehicle by means of spin, i.e. rotation along the longitudinal axis. The concept originates from conservation of angular momentum as applied to ballistics, where the spin is commonly obtained by means of rifling. For most satellite applications this approach has been superseded by three-axis stabilization. Use Spin-stabilization is used on rockets and spacecraft where attitude control is required without the requirement for on-board 3-axis propulsion or mechanisms, and sensors for attitude control and pointing. On rockets with a solid motor upper stage, spin stabilization is used to keep the motor from drifting off course as they don't have their own thrusters. Usually small rockets are used to spin up the spacecraft and rocket then fire the rocket and send the craft off. Rockets and spacecraft that use spin stabilization: * The Jupiter-C and Minotaur V launch vehicles used spin-stabiliza ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Cell
A solar cell, also known as a photovoltaic cell (PV cell), is an electronic device that converts the energy of light directly into electricity by means of the photovoltaic effect.Solar Cells chemistryexplained.com It is a type of photoelectric cell, a device whose electrical characteristics (such as Electric current, current, voltage, or Electrical resistance and conductance, resistance) vary when it is exposed to light. Individual solar cell devices are often the electrical building blocks of solar panel, photovoltaic modules, known colloquially as "solar panels". Almost all commercial PV cells consist of crystalline silicon, with a market share of 95%. Cadmium telluride thin-film solar cells account for the remainder. The common single-junction silicon solar cell can produce a maximum open-circuit voltage o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
