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IEEE 802.11 is part of the IEEE 802 set of local area network (LAN) protocols, and specifies the set of media access control (MAC) and physical layer (PHY) protocols for implementing wireless local area network (WLAN) Wi-Fi computer communication in various frequencies, including but not limited to 2.4 GHz, 5 GHz, 6 GHz, and 60 GHz frequency bands.
The ISM radio bands are portions of the radio spectrum reserved internationally for industrial, scientific and medical (ISM) purposes other than telecommunications. Examples of applications for the use of radio frequency (RF) energy in these bands include radio-frequency process heating, microwave ovens, and medical diathermy machines. The powerful emissions of these devices can create electromagnetic interference and disrupt radio communication using the same frequency, so these devices are limited to certain bands of frequencies. In general, communications equipment operating in these bands must tolerate any interference generated by ISM applications, and users have no regulatory protection from ISM device operation.
A communications satellite is an artificial satellite that relays and amplifies radio telecommunications signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. Communications satellites are used for television, telephone, radio, internet, and military applications. There are about 2,000 communications satellites in Earth's orbit, used by both private and government organizations. Many are in geostationary orbit 22,236 miles (35,785 km) above the equator, so that the satellite appears stationary at the same point in the sky, so the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track it.
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. 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 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, and numerous other applications.
Mars Express is a space exploration mission being conducted by the European Space Agency (ESA). The Mars Express mission is exploring the planet Mars, and is the first planetary mission attempted by the agency. "Express" originally referred to the speed and efficiency with which the spacecraft was designed and built. However "Express" also describes the spacecraft's relatively short interplanetary voyage, a result of being launched when the orbits of Earth and Mars brought them closer than they had been in about 60,000 years.
High frequency (HF) is the ITU designation for the range of radio frequency electromagnetic waves between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten decameters. Frequencies immediately below HF are denoted medium frequency (MF), while the next band of higher frequencies is known as the very high frequency (VHF) band. The HF band is a major part of the shortwave band of frequencies, so communication at these frequencies is often called shortwave radio. Because radio waves in this band can be reflected back to Earth by the ionosphere layer in the atmosphere – a method known as "skip" or "skywave" propagation – these frequencies are suitable for long-distance communication across intercontinental distances and for mountainous terrains which prevent line-of-sight communications. The band is used by international shortwave broadcasting stations (3.95–25.82 MHz), aviation communication, government time stations, weather stations, amateur radio and citizens band services, among other uses.
Mars Reconnaissance Orbiter (MRO) is a spacecraft designed to study the geology and climate of Mars, provide reconnaissance of future landing sites, and relay data from surface missions back to Earth. It was launched on August 12, 2005 and reached Mars on March 10, 2006. In November 2006, after five months of aerobraking, it entered its final science orbit and began its primary science phase. The cost to develop and operate MRO through the end of its prime mission in 2010 was US$716.6 million .
The X band is the designation for a band of frequencies in the microwave radio region of the electromagnetic spectrum. In some cases, such as in communication engineering, the frequency range of the X band is rather indefinitely set at approximately 7.0–11.2 GHz. In radar engineering, the frequency range is specified by the Institute of Electrical and Electronics Engineers (IEEE) at 8.0–12.0 GHz. The X band is used for radar, satellite communication, and wireless computer networks.
The radio spectrum is the part of the electromagnetic spectrum with frequencies from 30 Hz to 300 GHz. Electromagnetic waves in this frequency range, called radio waves, are widely used in modern technology, particularly in telecommunication. To prevent interference between different users, the generation and transmission of radio waves is strictly regulated by national laws, coordinated by an international body, the International Telecommunication Union (ITU).
The interplanetary Internet is a conceived computer network in space, consisting of a set of network nodes that can communicate with each other. These nodes are the planet's orbiters (satellites) and landers, and the earth ground stations. For example, the orbiters collect the scientific data from the Curiosity rover on Mars through near-Mars communication links, transmit the data to Earth though direct links from the Mars orbiters to the Earth ground stations, and finally the data can be routed through Earth's internal internet.
The Mars Telecommunications Orbiter (MTO) was a cancelled Mars mission that was originally intended to launch in 2009 and would have established an Interplanetary Internet between Earth and Mars. The spacecraft would have arrived in a high orbit above Mars in 2010 and relayed data packets to Earth from a variety of Mars landers, rovers and orbiters for as long as ten years, at an extremely high data rate. Such a dedicated communications satellite was thought to be necessary due to the vast quantity of scientific information to be sent to Earth by such landers as the Mars Science Laboratory.
IEEE 802.11p is an approved amendment to the IEEE 802.11 standard to add wireless access in vehicular environments (WAVE), a vehicular communication system. It defines enhancements to 802.11 required to support Intelligent Transportation Systems (ITS) applications. This includes data exchange between high-speed vehicles and between the vehicles and the roadside infrastructure, so called V2X communication, in the licensed ITS band of 5.9 GHz (5.85–5.925 GHz). IEEE 1609 is a higher layer standard based on the IEEE 802.11p. It is also the basis of a European standard for vehicular communication known as ETSI ITS-G5.
InterPlaNet (IPN), not to be confused with InterPlanetary Network, is a computer networking protocol designed to operate at interplanetary distances, where traditional protocols such as the Internet Protocol break down. It is the base for Interplanetary Internet. It has been under development by Vint Cerf and NASA since 1998 and a permanent network link to Mars was planned by 2008 until the Mars Telecommunications Orbiter was canceled in 2005. The protocol was expected to be space-qualified and ready for use by around 2010.
The beacon mode service is a Consultative Committee for Space Data Systems (CCSDS) telecommunications service aimed at spacecraft which are not communicated with via the Deep Space Network. It is primarily designed to relay a spacecraft's "health" information, and secondarily its telecommunications status, using a simple signal that can be detected with a moderately-sized antenna. Beacon mode also enables spacecraft to communicate with one another on a daily basis, allowing for one spacecraft to act as a data proxy for another.
Electra, formally called the Electra Proximity Link Payload, is a telecommunications package that acts as a communications relay and navigation aid for Mars spacecraft and rovers. The use of such a relay increases the amount of data that can be returned by two to three orders of magnitude.
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.
OPS-SAT is a CubeSat by the European Space Agency (ESA) and it is intended to demonstrate the improvements in mission control capabilities that will arise when satellites can fly more powerful on-board computers. The satellite features an experimental computer that is ten times more powerful than any current ESA spacecraft.
Mars Cube One was a Mars flyby mission launched on 5 May 2018 alongside NASA's InSight Mars lander mission. It consisted of two nanospacecraft, MarCO-A and MarCO-B, that provided a real-time communications link to Earth for InSight during its entry, descent, and landing (EDL) on 26 November 2018 - when InSight was out of line of sight from the Earth. Both spacecraft were 6U CubeSats, and the mission was a test of new miniaturized communications and navigation technologies. These were the first CubeSats to operate beyond Earth orbit, and aside from telecommunications they also tested CubeSats' endurance in deep space. On 5 February 2019, NASA reported that both the CubeSats had gone silent by 5 January 2019, and are unlikely to be heard from again. In August 2019, the CubeSats were honored for their role in the successful landing of the InSight lander on Mars.
The Iris transponder is a small, low power deep-space transponder designed by JPL for use in cubesats. It unifies a number of communication functions - receiver, command detector, telemetry modulator, exciters, and control functions - into one 1.2-kg package that occupies about 0.5 U. IRIS is designed to handle X band uplink, UHF receive, and both X band and optional Ka band downlink. It is only one third the mass, and lower power, compared to the smallest previous solution, the small deep space transponder.
References
- ↑ "CCSDS Recommendation For Proximity-1 Space Link Protocol. Coding And Synchronization Sublayer" (PDF). Retrieved 2017-05-22.
- ↑ "CCSDS Recommendation For Proximity-1 Space Link Protocol. Data Link Layer" (PDF). Retrieved 2017-05-22.
- ↑ "CCSDS Recommendation For Proximity-1 Space Link Protocol. Physical Layer" (PDF). Retrieved 2017-05-22.
- ↑ CCSDS Proximity-1 Communications Protocol Enables High-Speed Communication at Mars
- ↑ "Phoenix Mars Mission FAQ" . Retrieved 2008-05-26.