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Alexander (satellite)
Alexander, also known as PhoneSat 2.0 Beta or PhoneSat v2a is a technology demonstration satellite operated by NASA's Ames Research Center, which was launched in April 2013. Part of the PhoneSat programme, it was one of the first three PhoneSat spacecraft, and the first Phonesat-2.0 satellite, to be launched. A PhoneSat-2.0 satellite, ''Alexander'' was built to the single-unit (1U) CubeSat specification, and measures in each dimension. The satellite is based on an off-the-shelf Samsung Electronics Nexus S smartphone which serves in place of an onboard computer. The satellite is equipped with a two-way S-band transponder and solar cells for power generation. The spacecraft uses the phone's gyroscopes, along with a GPS receiver, to determine its position and orientation, and a system of reaction wheels and magnetorquer coils for attitude control. ''Alexander'' was named after Alexander Graham Bell, the inventor of the telephone. The two other PhoneSat spacecraft launched aboard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Technology Demonstration
A technology demonstration (or tech demo), also known as demonstrator model, is a prototype, rough example or an otherwise incomplete version of a conceivable product or future system, put together as proof of concept with the primary purpose of showcasing the possible applications, feasibility, performance and method of an idea for a new technology. They can be used as demonstrations to the investors, partners, journalists or even to potential customers in order to convince them of the viability of the chosen approach, or to test them on ordinary users. Computers and gaming Technology demonstrations are often used in the computer industry, emerging as an important tool in response to short development cycles, in both software and hardware development. * Computer game developers use tech demos to rouse and maintain interest to titles still in development (because game engines are usually ready before the art is finished) and to ensure functionality by early testing. Short segmen ... [...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, especially those 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. 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), wireless networking (WiFi), garage door openers, keyless vehicle locks, baby monitors as well as for medical diathermy machines and microwave ovens (typically at 2.495 GHz). India's regio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antares A-ONE
Antares A-ONE mission was the maiden flight of Orbital Sciences Corporation' Antares launch vehicle including the ascent to space and accurate delivery of a simulated payload, the Cygnus Mass Simulator (CMS), which was launched 21 April 2013. It was launched from Pad 0A at the Mid-Atlantic Regional Spaceport (MARS), Wallops Flight Facility, Virginia. The simulated payload simulates the mass of the Cygnus cargo spacecraft. This dummy payload was sent into an orbit of with an orbital inclination of 51.6°, the same launch profile it will use for Orbital's upcoming cargo supply missions to the International Space Station (ISS) for NASA. This launch along with several other activities leading up to it, are paid milestones under NASA's Commercial Orbital Transportation Services (COTS) program. Primary payload The primary payload was the Cygnus Mass Simulator. It had a height of , a diameter of and a mass of . It was equipped with 22 accelerometers, 2 microphones, 12 digital ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planet Labs
Planet Labs PBC (formerly Planet Labs, Inc. and Cosmogia, Inc.) is an American public Earth imaging company based in San Francisco, California. Their goal is to image the entirety of the Earth daily to monitor changes and pinpoint trends. The company designs and manufactures Triple-CubeSat miniature satellites called Doves that are then delivered into orbit as secondary payloads on other rocket launch missions. Each ''Dove'' is equipped with a high-powered telescope and camera programmed to capture different swaths of Earth. Each ''Dove'' Earth observation satellite continuously scans Earth, sending data once it passes over a ground station, by means of a frame image sensor. The images gathered by ''Doves'', which can be accessed online and some of which is available under an open data access policy, provide up-to-date information relevant to climate monitoring, crop yield prediction, urban planning, and disaster response. With acquisition of BlackBridge in July 2015, Planet La ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bell (satellite)
Bell, also known as PhoneSat 1.0b or PhoneSat v1b was a technology demonstration satellite operated by NASA's Ames Research Center, which was launched in April 2013. Part of the PhoneSat programme, it was one of the first three PhoneSat spacecraft to be launched. A PhoneSat-1.0 satellite, ''Bell'' was built to the single-unit (1U) CubeSat specification, and measures in each dimension. The satellite is based on an off-the-shelf HTC Nexus One smartphone which serves in place of an onboard computer and avionics system. Unlike the more advanced PhoneSat-2.0 spacecraft, ''Bell'' is powered by non-rechargeable batteries, and has no attitude control system, however onboard sensors can be used to determine and monitor the satellite's attitude. The cameras built into the phones aboard ''Bell'' and its sister satellite ''Graham'' have been used to return images of the Earth from space. Unlike ''Graham'', Bell has an external Iridium modem attached to one of its side. Independent battery can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graham (satellite)
Graham, also known as PhoneSat 1.0a or PhoneSat v1a was a technology demonstration satellite operated by NASA's Ames Research Center, which was launched in April 2013. Part of the PhoneSat programme, it was one of the first three PhoneSat spacecraft to be launched. A PhoneSat-1.0 satellite, ''Graham'' was built to the single-unit (1U) CubeSat specification, and measures in each dimension. The satellite is based on an off-the-shelf HTC Nexus One smartphone which serves in place of an onboard computer and avionics system. Unlike the more advanced PhoneSat-2.0 spacecraft, ''Graham'' is powered by non-rechargeable batteries, and has no attitude control system, however onboard sensors can be used to determine and monitor the satellite's attitude. The cameras built into the phones aboard ''Graham'' and its sister satellite ''Bell'' was used to return images of the Earth from space. ''Graham'' was named after Alexander Graham Bell, the inventor of the telephone. The two other PhoneSat sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone
A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into electronic signals that are transmitted via cables and other communication channels to another telephone which reproduces the sound to the receiving user. The term is derived from el, τῆλε (''tēle'', ''far'') and φωνή (''phōnē'', ''voice''), together meaning ''distant voice''. A common short form of the term is ''phone'', which came into use early in the telephone's history. In 1876, Alexander Graham Bell was the first to be granted a United States patent for a device that produced clearly intelligible replication of the human voice at a second device. This instrument was further developed by many others, and became rapidly indispensable in business, government, and in households. The essential elements of a telephone are a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Graham Bell
Alexander Graham Bell (, born Alexander Bell; March 3, 1847 – August 2, 1922) was a Scottish-born inventor, scientist and engineer who is credited with patenting the first practical telephone. He also co-founded the American Telephone and Telegraph Company (AT&T) in 1885. Bell's father, grandfather, and brother had all been associated with work on elocution and speech, and both his mother and wife were deaf; profoundly influencing Bell's life's work. His research on hearing and speech further led him to experiment with hearing devices which eventually culminated in Bell being awarded the first U.S. patent for the telephone, on March 7, 1876. Bell considered his invention an intrusion on his real work as a scientist and refused to have a telephone in his study. Many other inventions marked Bell's later life, including groundbreaking work in optical telecommunications, hydrofoils, and aeronautics. Bell also had a strong influence on the National Geographic Society and its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spacecraft Attitude Control
Spacecraft attitude control is the process of controlling the orientation of a spacecraft (vehicle/satellite) with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc. Controlling vehicle attitude requires sensors to measure vehicle orientation, actuators to apply the torques needed to orient the vehicle to a desired attitude, and algorithms to command the actuators based on (1) sensor measurements of the current attitude and (2) specification of a desired attitude. The integrated field that studies the combination of sensors, actuators and algorithms is called guidance, navigation and control (GNC). Overview A spacecraft's attitude must typically be stabilized and controlled for a variety of reasons. It is often needed so that the spacecraft high-gain antenna may be accurately pointed to Earth for communications, so that onboard experiments may accomplish precise pointing for accurate collectio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetorquer
A magnetorquer or magnetic torquer (also known as a torque rod) is a satellite system for attitude control, detumbling, and stabilization built from electromagnetic coils. The magnetorquer creates a magnetic dipole that interfaces with an ambient magnetic field, usually Earth's, so that the counter-forces produced provide useful torque. Functional principle Magnetorquers are essentially sets of electromagnets laid out to yield a rotationally asymmetric (anisotropic) magnetic field over an extended area. That field is controlled by switching current flow through the coils on or off, usually under computerized feedback control. The magnets themselves are mechanically anchored to the craft, so that any magnetic force they exert on the surrounding magnetic field will lead to a magnetic reverse force and result in mechanical torque about the vessel's center of gravity. This makes it possible to freely pivot the craft around in a known local gradient of the magnetic field by only using ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reaction Wheel
A reaction wheel (RW) is used primarily by spacecraft for three-axis attitude control, and does not require rockets or external applicators of torque. 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 as (and referred to as) a momentum wheel, by operating it 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 parallel to the wheel's spin axis) do not result directly in spacecraft angular motion about the same axis as the disturbance torque; instead, they result in (generally smaller) angular motion (precession) of that spacecraft axis about a perpendicular axis. This has the effect of tending to stabilize that spacecraft ax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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