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Surveyor 6
Surveyor 6 was the sixth lunar lander of the American uncrewed Surveyor program that reached the surface of the Moon. Surveyor 6 landed on the Sinus Medii. A total of 30,027 images were transmitted to Earth. This spacecraft was the fourth of the Surveyor series to successfully achieve a soft landing on the Moon, obtain post landing television pictures, determine the abundance of the chemical elements in the lunar soil, obtain touchdown dynamics data, obtain thermal and radar reflectivity data, and conduct a Vernier engine erosion experiment. Virtually identical to Surveyor 5, this spacecraft carried a television camera, a small bar magnet attached to one footpad, and an alpha-scattering instrument as well as the necessary engineering equipment. It landed on November 10, 1967, in Sinus Medii, 0.49 deg in latitude and 1.40 deg w longitude (selenographic coordinates)–the center of the Moon's visible hemisphere. The spacecraft accomplished all planned objectives. The successful comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lander (spacecraft)
A lander is a spacecraft that descends towards, comes to rest on, the surface of an astronomical body. In contrast to an impact probe, which makes a hard landing that damages or destroys the probe upon reaching the surface, a lander makes a soft landing after which the probe remains functional. For bodies with atmospheres, the landing occurs after atmospheric entry. In these cases, landers may employ parachutes to slow them down enough to maintain a low terminal velocity. In some cases, small landing rockets will be fired just before impact in order to reduce the lander's velocity. Landing may be accomplished by controlled descent and set down on landing gear, with the possible addition of a post-landing attachment mechanism (such as the mechanism used by ''Philae'') for celestial bodies with low gravity. Some missions (for example, Luna 9 and Mars Pathfinder) used inflatable airbags to cushion the lander's impact rather than utilizing more traditional landing gear. When a hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vidicon
Video camera tubes were devices based on the cathode ray tube that were used in television cameras to capture television images, prior to the introduction of charge-coupled device (CCD) image sensors in the 1980s. Several different types of tubes were in use from the early 1930s, and as late as the 1990s. In these tubes, an cathode ray, electron beam was scanned across an image of the scene to be broadcast focused on a target. This generated a current that was dependent on the brightness of the image on the target at the scan point. The size of the striking ray was tiny compared to the size of the target, allowing 483 horizontal scan lines per image in the NTSC format, 576 lines in PAL, and as many as 1035 lines in Multiple sub-Nyquist sampling encoding, Hi-Vision. Cathode ray tube Any vacuum tube which operates using a focused beam of electrons, originally called cathode rays, is known as a cathode ray tube (CRT). These are usually seen as display devices as used in older (i.e. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Artificial Objects On The Moon
This is a partial list of artificial materials left on the Moon, many during the missions of the Apollo program. The table below does not include lesser Apollo mission artificial objects, such as a hammer and other tools, retroreflectors, Apollo Lunar Surface Experiments Packages, or the commemorative, artistic, and personal objects left by the twelve Apollo astronauts, such as the United States flags, the commemorative plaques attached to the ladders of the six Apollo Lunar Modules, the silver astronaut pin left by Alan Bean in honor of Clifton C. Williams whom he replaced, the Bible left by David Scott, the ''Fallen Astronaut'' statuette and memorial plaque placed by the crew of Apollo 15, the Apollo 11 goodwill messages disc, or the golf balls Alan Shepard hit during an Apollo 14 moonwalk. Five S-IVB third stages of Saturn V rockets from the Apollo program crashed into the Moon, and are the heaviest human-made objects on the lunar surface. Humans have left over of material o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mars Geyser Hopper
The Mars Geyser Hopper (MGH) is a NASA design reference mission for a Discovery-class spacecraft concept that would investigate the springtime carbon dioxide Martian geysers found in regions around the south pole of Mars. The power technology that MGH proposed to use was the Advanced Stirling radioisotope generator ( ASRG). NASA finished the ASRG design and made one test unit of the device but the program was concluded by the mid-2010s. Neither InSight nor any of the next Discovery's semi-finalists use the ASRG or an RTG due to high demand and limited supply of the type of plutonium it relies on. Background The Discovery program was started in the 1990s following discussions at NASA for a new program, and has achieved such missions as ''Genesis'', ''Deep Impact'' and ''Kepler'' among others; this is the program this mission was designed for selection in, at least initially. One of the first unmanned robotic spacecraft to do a hop was Surveyor 6 lunar lander, which successfu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulse Height Analyzer
A pulse-height analyzer (PHA) is an instrument that accepts electronic pulses of varying heights from particle and event detectors, digitizes the pulse heights, and saves the number of pulses of each height in registers or channels, thus recording a pulse-height spectrum or pulse-height distribution used for later pulse-height analysis. PHAs are used in nuclear- and elementary-particle physics research. A PHA is a specific modification to multichannel analyzers. A pulse-height analyzer is also integrated into particle counters or used as a discrete module to calibrate particle counters. See also * Nuclear electronics Nuclear electronics is a subfield of electronics concerned with the design and use of high-speed electronic systems for nuclear physics and elementary particle physics research, and for industrial and medical use. Essential elements of such systems ... Experimental particle physics {{nuclear-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tape Recorder
An audio tape recorder, also known as a tape deck, tape player or tape machine or simply a tape recorder, is a sound recording and reproduction device that records and plays back sounds usually using magnetic tape for storage. In its present-day form, it records a fluctuating signal by moving the tape across a tape head that polarizes the magnetic domains in the tape in proportion to the audio signal. Tape-recording devices include the reel-to-reel tape deck and the cassette deck, which uses a cassette for storage. The use of magnetic tape for sound recording originated around 1930 in Germany as paper tape with oxide lacquered to it. Prior to the development of magnetic tape, magnetic wire recorders had successfully demonstrated the concept of magnetic recording, but they never offered audio quality comparable to the other recording and broadcast standards of the time. This German invention was the start of a long string of innovations that have led to present-day magnetic t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphor
A phosphor is a substance that exhibits the phenomenon of luminescence; it emits light when exposed to some type of radiant energy. The term is used both for fluorescent or phosphorescent substances which glow on exposure to ultraviolet or visible light, and cathodoluminescent substances which glow when struck by an electron beam (cathode rays) in a cathode-ray tube. When a phosphor is exposed to radiation, the orbital electrons in its molecules are excited to a higher energy level; when they return to their former level they emit the energy as light of a certain color. Phosphors can be classified into two categories: fluorescent substances which emit the energy immediately and stop glowing when the exciting radiation is turned off, and phosphorescent substances which emit the energy after a delay, so they keep glowing after the radiation is turned off, decaying in brightness over a period of milliseconds to days. Fluorescent materials are used in applications in which the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Directional Antenna
A directional antenna or beam antenna is an antenna which radiates or receives greater power in specific directions allowing increased performance and reduced interference from unwanted sources. Directional antennas provide increased performance over dipole antennas—or omnidirectional antennas in general—when greater concentration of radiation in a certain direction is desired. A high-gain antenna (HGA) is a directional antenna with a focused, narrow radiowave beam width, permitting more precise targeting of the radio signals. Most commonly referred to during space missions, these antennas are also in use all over Earth, most successfully in flat, open areas where there are no mountains to disrupt radiowaves. By contrast, a low-gain antenna (LGA) is an omnidirectional antenna with a broad radiowave beam width, that allows the signal to propagate reasonably well even in mountainous regions and is thus more reliable regardless of terrain. Low-gain antennas are often used in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bandwidth (signal Processing)
Bandwidth is the difference between the upper and lower frequencies in a continuous band of frequencies. It is typically measured in hertz, and depending on context, may specifically refer to ''passband bandwidth'' or ''baseband bandwidth''. Passband bandwidth is the difference between the upper and lower cutoff frequencies of, for example, a band-pass filter, a communication channel, or a signal spectrum. Baseband bandwidth applies to a low-pass filter or baseband signal; the bandwidth is equal to its upper cutoff frequency. Bandwidth in hertz is a central concept in many fields, including electronics, information theory, digital communications, radio communications, signal processing, and spectroscopy and is one of the determinants of the capacity of a given communication channel. A key characteristic of bandwidth is that any band of a given width can carry the same amount of information, regardless of where that band is located in the frequency spectrum. For example, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Omnidirectional Antenna
In radio communication, an omnidirectional antenna is a class of antenna which radiates equal radio power in all directions perpendicular to an axis (azimuthal directions), with power varying with angle to the axis (elevation angle), declining to zero on the axis. When graphed in three dimensions ''(see graph)'' this radiation pattern is often described as ''doughnut-shaped''. Note that this is different from an isotropic antenna, which radiates equal power in ''all'' directions, having a ''spherical'' radiation pattern. Omnidirectional antennas oriented vertically are widely used for nondirectional antennas on the surface of the Earth because they radiate equally in all horizontal directions, while the power radiated drops off with elevation angle so little radio energy is aimed into the sky or down toward the earth and wasted. Omnidirectional antennas are widely used for radio broadcasting antennas, and in mobile devices that use radio such as cell phones, FM radios, walkie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azimuth
An azimuth (; from ar, اَلسُّمُوت, as-sumūt, the directions) is an angular measurement in a spherical coordinate system. More specifically, it is the horizontal angle from a cardinal direction, most commonly north. Mathematically, the relative position vector from an observer (origin) to a point of interest is projected perpendicularly onto a reference plane (the horizontal plane); the angle between the projected vector and a reference vector on the reference plane is called the azimuth. When used as a celestial coordinate, the azimuth is the horizontal direction of a star or other astronomical object in the sky. The star is the point of interest, the reference plane is the local area (e.g. a circular area with a 5 km radius at sea level) around an observer on Earth's surface, and the reference vector points to true north. The azimuth is the angle between the north vector and the star's vector on the horizontal plane. Azimuth is usually measured in d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Filter
Color (American English) or colour (British English) is the visual perceptual property deriving from the spectrum of light interacting with the photoreceptor cells of the eyes. Color categories and physical specifications of color are associated with objects or materials based on their physical properties such as light absorption, reflection, or emission spectra. By defining a color space, colors can be identified numerically by their coordinates. Because perception of color stems from the varying spectral sensitivity of different types of cone cells in the retina to different parts of the spectrum, colors may be defined and quantified by the degree to which they stimulate these cells. These physical or physiological quantifications of color, however, do not fully explain the psychophysical perception of color appearance. Color science includes the perception of color by the eye and brain, the origin of color in materials, color theory in art, and the physics of electromag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
