Marketed as the center of the new broadband satellite networks are a new generation of high-powered GEO satellites positioned 35786 km above the equator, operating in K a -band (18.3–30 GHz) mode. These new purpose-built satellites are designed and optimized for broadband applications, employing many narrow spot beams, which target a much smaller area than the broad beams used by earlier communication satellites. This spot beam technology allows satellites to reuse assigned bandwidth multiple times which can enable them to achieve much higher overall capacity than conventional broad beam satellites. The spot beams can also increase performance and consequential capacity by focusing more power and increased receiver sensitivity into defined concentrated areas. Spot beams are designated as one of two types: subscriber spot beams, which transmit to and from the subscriber-side terminal, and gateway spot beams, which transmit to/from a service provider ground station. Note that moving off the tight footprint of a spotbeam can degrade performance significantly. Also, spotbeams can make the use of other significant new technologies impossible, including 'Carrier in Carrier' modulation.
In conjunction with the satellite's spot-beam technology, a bent-pipe architecture has traditionally been employed in the network in which the satellite functions as a bridge in space, connecting two communication points on the ground. The term "bent-pipe" is used to describe the shape of the data path between sending and receiving antennas, with the satellite positioned at the point of the bend. Simply put, the satellite's role in this network arrangement is to relay signals from the end user's terminal to the ISP's gateways, and back again without processing the signal at the satellite. The satellite receives, amplifies, and redirects a carrier on a specific radio frequency through a signal path called a transponder.
The satellite has its own set of antennas to receive communication signals from Earth and to transmit signals to their target location. These antennas and transponders are part of the satellite's "payload", which is designed to receive and transmit signals to and from various places on Earth. What enables this transmission and reception in the payload transponders is a repeater subsystem (RF (radio frequency) equipment) used to change frequencies, filter, separate, amplify and group signals before routing them to their destination address on Earth. The satellite's high-gain receiving antenna passes the transmitted data to the transponder which filters, translates and amplifies them, then redirects them to the transmitting antenna on board. The signal is then routed to a specific ground location through a channel known as a carrier. Beside the payload, the other main component of a communications satellite is called the bus, which comprises all equipment required to move the satellite into position, supply power, regulate equipment temperatures, provide health and tracking information, and perform numerous other operational tasks.
Some proposed satellite constellations in LEO such as SpaceX's Starlink, Telesat's constellation and LeoSat will employ laser communication equipment for high-throughput optical inter-satellite links. The interconnected satellites allow for direct routing of user data from satellite to satellite and effectively create a space-based optical mesh network that will enable seamless network management and continuity of service.
Fixed satellite services handle hundreds of billions of voice, data, and video transmission tasks across all countries and continents between certain points on the Earth's surface.
Mobile satellite systems help connect remote regions, vehicles, ships, people and aircraft to other parts of the world and/or other mobile or stationary communications units, in addition to serving as navigation systems.
Portfolios are more than a collection of financial assets and the satellite investments must be selected and managed considering the portfolio as a whole. The satellite should improve not only the return but the risk/return profile of the portfolio, and not only quantitatively (the Sharpe ratio or whatever other risk/return measures used) but also qualitatively, by adding sources of value (e.g. non-correlated strategies, short and medium-term investment ideas, risk-asymmetric assets, etc.) different from that in the core but still consistent with the market and economic view and the client's financial planning goals.
It is also possible to offer discontinuous coverage using a low-Earth-orbit satellite capable of storing data received while passing over one part of Earth and transmitting it later while passing over another part. This will be the case with the CASCADE system of Canada's CASSIOPE communications satellite. Another system using this store and forward method is Orbcomm.
The "Satellite" portion, by contrast, comprises holdings that the advisor expects will add alpha, the financial term for returns exceeding systemic. Holdings may include actively managed stocks, mutual funds, and separate account managers with a particular sector, region of positions, or Micro or Mega Cap Company Holdings, or passively managed assets with a particular style that is counter to, or even enhances, the style bias of the core. Short holding periods and tax-inefficient positions may result in short-term capital gains or losses.
This satellite allocation may be implemented into 100% equity allocations and/or allocations that blend with fixed-income or non-equity positions. The satellite portfolio may be used occasionally for fixed-income investing (emerging market debt, junk bonds, individual bonds) but generally it is dedicated to: equities and alternative assets such as: hedge funds, REITs, commodities, options, and foreign currencies. Principal protected notes may also be used; these investments are truly hybrid in that they provide a guaranteed return of principal while providing upside participation in a number of equity and alternative-investments asset classes.
If the entire allotment of the satellite portion is not deemed worthy of inclusion, that portion will either be reallocated across "core" positions or in a "satellite holder"—a position that mirrors some aspect of the core (generally the position most closely resembling the benchmark) that is quickly traded when an opportunity is identified without causing major tax implications (e.g., issues with FIFO based trades).
In 2012 Satellite began incorporating short film, video and stop motion animation into live performances. Satellite's first major short film, "Twin Star Event," was premiered by the Grand Rapids Art Museum (GRAM) for ArtPrize in 2014.
STARSHINE-2 and -3 had systems added to impart spin to these satellites in an effort to improve the solar-reflected flash rate, as well as a number of laser retroreflectors to introduce the students to satellite laser ranging. The satellites were constructed largely from spare flight hardware.
A group of satellites working in concert is known as a satellite constellation. Two such constellations, intended to provide satellite phone services, primarily to remote areas, are the Iridium and Globalstar systems. The Iridium system has 66 satellites.
A satellite modem is not the only device needed to establish a communication channel. Other equipment that are essential for creating a satellite link include satellite antennas and frequency converters.
Similarly, a signal received from a satellite is firstly downconverted (this is done by a Low-noise block converter - LNB), then demodulated by a modem, and at last handled by data terminal equipment. The LNB is usually powered by the modem through the signal cable with 13 or 18 V DC
Since October 1967 satellite based weapons systems have been limited by international treaty to conventional weapons only. Art.IV of the Outer Space Treaty specifically prohibits signatories from installing weapons of mass destruction in Earth orbit. The treaty became effective on 10 October 1967 and, as of May 2013, 102 countries are parties to the treaty with a further 27 pending full ratification.
The satellite employs a Drag-Free Attitude Control System (DFACS), also called the Acceleration and Attitude Control System (AACS), that uses a double-redundant primary and backup set of four microthrusters (sixteen total) to "fly" the satellite around the test masses. This system takes into account the dynamic forces acting on the spacecraft, including aerodynamic forces due to residual atmosphere, solar pressure forces due to photon impacts, electromagnetic forces within the Earth's magnetosphere, and gravitational forces in the Sun-Earth-Moon system.
STARSHINE-1 was a spherical satellite that was fitted with almost nine hundred small mirrors polished by students from around the world. Once launched, a network of over 20,000 students from eighteen countries tracked the satellite by observing sunlight glinting off the mirrors and networked their observations via the Internet. The students used these observations to calculate air drag, solar activity, and other orbit related properties of the satellite.
In the United States, research into satellite based weapons was initiated by President Dwight D. Eisenhower in the 1950s. In 1958, the United States initiated Project Defender to develop an anti-ICBM solution launched from satellites. The satellites would have deployed a huge wire mesh to disable ICBMs during their early launch phase. The project floundered due to the lack of any mechanism to protect the satellites from attack resulting in the cancellation of Defender in 1968.