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AMSAT-OSCAR 16
AMSAT-OSCAR 16, also known as AO-16 and PACSAT, is the in-orbit name designation of an amateur radio satellite of the OSCAR series. It was built by AMSAT and was launched on 22 January 1990 from Kourou, French Guiana on an Ariane 4 launch vehicle. It is in sun synchronous low Earth orbit. Discussion Based on the success of UoSAT-OSCAR-11's Digital Communications Experiment, AMSAT-OSCAR-16 was designed to be a dedicated store-and-forward file server in space. Using 1200 bit per second Mode JD radio links, AMSAT-OSCAR-16 interacts with ground station terminal software to appear as a packet radio bulletin board system to the user. Anyone wishing to download files, personal mail from anywhere in the world, or news bulletins could request the information be "broadcast" to all under the footprint of the spacecraft, or directed specifically to that ground station. This broadcast protocol differs from terrestrial packet radio communications, but allows a greater number of ground stati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AMSAT
AMSAT is a name for amateur radio satellite organizations worldwide, but in particular the Radio Amateur Satellite Corporation (AMSAT) with headquarters at Washington, D.C. AMSAT organizations design, build, arrange launches for, and then operate (command) satellites carrying amateur radio payloads, including the OSCAR series of satellites. Other informally affiliated national organizations exist, such as AMSAT Germany (AMSAT-DL) and AMSAT Japan (JAMSAT). History AMSAT was founded in 1969 in Washington, D.C. to continue the efforts begun by Project OSCAR. Its first project was to coordinate the launch of OSCAR 5, constructed by students at the University of Melbourne. Some design modifications were needed and were made by AMSAT members, and the satellite was successfully launched on 30 January 1970, on a NASA Thor Delta launch vehicle. AMSAT's next launch was AMSAT-OSCAR 6 (AO-6) on 15 October 1972. AO-6 was AMSAT's first long-life satellite, and was built with participan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Radio Satellite
An amateur radio satellite is an artificial satellite built and used by amateur radio operators. It forms part of the Amateur-satellite service. These satellites use amateur radio frequency allocations to facilitate communication between amateur radio stations. Many amateur satellites receive an OSCAR designation, which is an acronym for Orbiting Satellite Carrying Amateur Radio. The designation is assigned by AMSAT, an organization which promotes the development and launch of amateur radio satellites. Because of the prevalence of this designation, amateur radio satellites are often referred to as OSCARs. These satellites can be used free of charge by licensed amateur radio operators for voice ( FM, SSB) and data (AX.25, packet radio, APRS) communications. Currently, over 18 fully operational amateur radio satellites are in orbit. They may be designed to act as repeaters, as linear transponders, and as store and forward digital relays. Amateur radio satellites have helpe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Radio Satellites
An amateur () is generally considered a person who pursues an avocation independent from their source of income. Amateurs and their pursuits are also described as popular, informal, self-taught, user-generated, DIY, and hobbyist. History Historically, the amateur was considered to be the ideal balance between pure intent, open mind, and the interest or passion for a subject. That ideology spanned many different fields of interest. It may have its roots in the ancient Greek philosophy of amateur athletes competing in the Olympics. The ancient Greek citizens spent most of their time in other pursuits, but competed according to their natural talents and abilities. The "gentleman amateur" was a phenomenon among the gentry of Great Britain from the 17th century until the 20th century. With the start of the Age of Reason, with people thinking more about how the world works around them, (see science in the Age of Enlightenment), things like the cabinets of curiosities, and the wri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
70-centimeter Band
The 70-centimeter or 440 MHz band is a portion of the UHF radio spectrum internationally allocated to amateur radio and amateur satellite use. The ITU amateur radio allocation is from 430 to 440 MHz; however, some countries, such as the United States, allocate hams 420 to 450 MHz. Depending on the country the band is shared with other radio services (in United States with government radar systems such as PAVE PAWS). 70 centimeters is a popular ham band due to the ready availability of equipment in both new and used markets. Most amateurs operating on 70 cm use either equipment purpose-built for ham radio, or commercial equipment designed for nearby land mobile frequencies. Amateurs predominately use the band for FM or digital voice communications through repeaters (useful for emergency communications), as well narrow band modes (analog and digital) for long-distance communications (called "DX", including Moonbounce). The band is also popular for Amateur Satellite Ser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Random-access Memory
Random-access memory (RAM; ) is a form of computer memory that can be read and changed in any order, typically used to store working Data (computing), data and machine code. A Random access, random-access memory device allows data items to be read (computer), read or written in almost the same amount of time irrespective of the physical location of data inside the memory, in contrast with other direct-access data storage media (such as hard disks, CD-RWs, DVD-RWs and the older Magnetic tape data storage, magnetic tapes and drum memory), where the time required to read and write data items varies significantly depending on their physical locations on the recording medium, due to mechanical limitations such as media rotation speeds and arm movement. RAM contains multiplexer, multiplexing and demultiplexing circuitry, to connect the data lines to the addressed storage for reading or writing the entry. Usually more than one bit of storage is accessed by the same address, and RAM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UoSAT-2
UoSAT-2, which is also known as UO-11 and OSCAR-11, is a British satellite orbiting in Low Earth Orbit. The satellite functions as an amateur radio transmitter (known as an OSCAR) and was built at the University of Surrey. It launched into orbit in March 1984 and remains orbital and active, though unstable with irregular periods of transmission. All of the Analog telemetry channels have failed, making telemetry from OSCAR 11 useless. The satellite was still heard transmitting telemetry in 2015, thirty years after launch. It was operated by Surrey Satellite Technology Ltd. (SSTL). Characteristics The satellite was the second in the UoSAT series of satellites built by University of Surrey; preceded by UoSAT-1 and followed by UoSAT-3. The satellite carries a Digitalker speech synthesiser, magnetometers, a CCD camera, a Geiger-Müller tube, and a microphone to detect the vibrations of micrometeoroid impacts. Like UoSAT-1 it transmits telemetry data on the VHF beacon at 1200 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low Earth Orbit
A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never more than about one-third of the radius of Earth. The term ''LEO region'' is also used for the area of space below an altitude of (about one-third of Earth's radius). Objects in orbits that pass through this zone, even if they have an apogee further out or are sub-orbital, are carefully tracked since they present a collision risk to the many LEO satellites. All crewed space stations to date have been within LEO. From 1968 to 1972, the Apollo program's lunar missions sent humans beyond LEO. Since the end of the Apollo program, no human spaceflights have been beyond LEO. Defining characteristics A wide variety of sources define LEO in terms of altitude. The altitude of an object in an elliptic orbit can vary significantly along the orbit. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sun-synchronous Orbit
A Sun-synchronous orbit (SSO), also called a heliosynchronous orbit, is a nearly polar orbit around a planet, in which the satellite passes over any given point of the planet's surface at the same local mean solar time. More technically, it is an orbit arranged so that it precesses through one complete revolution each year, so it always maintains the same relationship with the Sun. Applications A Sun-synchronous orbit is useful for imaging, reconnaissance, and weather satellites, because every time that the satellite is overhead, the surface illumination angle on the planet underneath it is nearly the same. This consistent lighting is a useful characteristic for satellites that image the Earth's surface in visible or infrared wavelengths, such as weather and spy satellites, and for other remote-sensing satellites, such as those carrying ocean and atmospheric remote-sensing instruments that require sunlight. For example, a satellite in Sun-synchronous orbit might ascend acros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
French Guiana
French Guiana ( or ; french: link=no, Guyane ; gcr, label=French Guianese Creole, Lagwiyann ) is an overseas departments and regions of France, overseas department/region and single territorial collectivity of France on the northern Atlantic Ocean, Atlantic coast of South America in the Guianas. It borders Brazil to the east and south and Suriname to the west. With a land area of , French Guiana is the second-largest Regions of France, region of France (more than one-seventh the size of Metropolitan France) and the largest Special member state territories and the European Union, outermost region within the European Union. It has a very low population density, with only . (Its population is less than that of Metropolitan France.) Half of its 294,436 inhabitants in 2022 lived in the metropolitan area of Cayenne, its Prefectures in France, capital. 98.9% of the land territory of French Guiana is covered by forests, a large part of which is Old-growth forest, primeval Tropical r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dove-OSCAR 17
Dove-OSCAR 17 (a.k.a. DO-17 or Microsat 2) is a Brazilian educational and amateur radio satellite ( BRAMSAT) (AMSAT-BRAZIL) launched on 22 January 1990. Project Dove-OSCAR 17 is one of the results of the so-called Microsat project by AMSAT, manufactured in the 1980s by the civil and electric engineer Junior Torres de Castro (amateur radio operator with callsign PY2BJO), who had been developing his ideas since 1957. He has built, with his own resources, the first artificial satellite for educational and humanitarian purposes: the "Dove". The device, assembled in a garage in Botucatu, São Paulo, was meant to provide synthesised peace messages for educational institutions at a time when the Cold War was still determining international relations around the world. It has a Digital Orbiting Voice Encoder (DOVE), designed to emit the synthesised voice messages, and also telemetry data transmission (FM Packet AFSK 1200 AX.25 at 145.825 MHz). It is box shaped with dimensions o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ariane 4
The Ariane 4 was a European expendable space launch system, developed by the ''Centre national d'études spatiales'' (CNES), the French space agency, for the European Space Agency (ESA). It was manufactured by ArianeGroup and marketed by Arianespace. Since its first flight on 15 June 1988 until the final flight on 15 February 2003, it attained 113 successful launches out of 116 total launches. In 1982, the Ariane 4 program was approved by ESA. Drawing heavily upon the preceding Ariane 3, it was designed to provide a launcher capable of delivering heavier payloads and at a lower cost per kilogram than the earlier members of the Ariane family. The Ariane 4 was principally an evolution of the existing technologies used, as opposed to being revolutionary in its design ethos; this approach quickly gained the backing of most ESA members, who funded and participated in its development and operation. Capable of being equipped with a wide variety of strap-on boosters, the Ariane 4 gaine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UoSAT-4
UoSAT-4, also known as UO-15 and OSCAR-15, is a British satellite in Low Earth Orbit. It was built by a spin-off company of the University of Surrey, Surrey Satellite Technology (SSTL) and launched in January 1990 from French Guiana. UoSAT-4 was launched on the same rocket as its sister satellite, UoSAT-3. Mission UoSAT-4 carried equipment to supplement UoSAT-3, but failed after two days in orbit. The satellite forms part of the growing amounts of orbital debris Space debris (also known as space junk, space pollution, space waste, space trash, or space garbage) are defunct human-made objects in space—principally in Earth orbit—which no longer serve a useful function. These include derelict spacecr ... orbiting around the Earth. The payload will decay in the Earth's atmosphere some time in the future. References University of Surrey Satellites orbiting Earth Amateur radio satellites Satellites of the United Kingdom Spacecraft launched in 1990 {{U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
