The Manned Space Flight Network (abbreviated MSFN, pronounced "misfin") was a set of tracking stations built to support the American Mercury, Gemini, Apollo, and Skylab space programs.
There were two other NASA space communication networks at the time, the Spacecraft Tracking and Data Acquisition Network (STADAN) for tracking satellites in low Earth orbit, and the Deep Space Network (DSN) for tracking more distant uncrewed missions. After the end of Skylab, the MSFN and STADAN were merged to form the Spaceflight Tracking and Data Network (STDN). STDN was in turn replaced by the satellite-based Tracking and Data Relay Satellite System (TDRSS) during the Space Shuttle program, being used as of 2009 [update] . [1]
Tracking vehicles in low Earth orbits (LEO) is quite different from tracking deep space missions. Deep space missions are visible for long periods of time from a large portion of the Earth's surface, and so require few stations (the DSN uses only three, as of February 20,2010 [update] ). These few stations, however, require the use of huge antennas and ultra-sensitive receivers to cope with the very distant, weak signals. Low Earth orbit missions, on the other hand, are only visible from a small fraction of the Earth's surface at a time, and the satellites move overhead quickly, which requires a large number of tracking stations, spread all over the world. The antennas required for LEO tracking and communication are not required to be as large as those used for deep space, but they must be able to track quickly.
These differing requirements led NASA to build a number of independent tracking networks, each optimized for its own mission. Prior to the mid-1980s, when the Tracking and Data Relay Satellite System (TDRSS) satellites became operational, NASA used several networks of ground-based antennas to track and communicate with Earth orbiting spacecraft. For the Mercury, Gemini, and Apollo missions, these were the primary means of communication, with the Deep Space Network (DSN) being assigned a supporting/backup role. [1]
The Mercury Space Flight Network (MSFN) was completed in 1961, and consisted of 18 ground tracking stations and two ships in the Atlantic and Indian Oceans to close gaps between ground stations. [2] [3] [4]
There was some variation between flights. For example, between MA-6 and MA-7 the Mid-Atlantic Ship was removed and the Indian Ocean Ship was repositioned to the Mozambique Channel.
A Pacific Ocean ship (USNS Wheeling) and the Goldstone Deep Space Communications Complex (GDS), California were used during Gordon Cooper's 1963 MA-9 flight. On MA-9 the Bermuda FPS-16 radar was the only radar on the entire network that had track during the capsule's insertion into an orbital track, and thus was vital to the verification of proper orbit. The next station to have contact was the Canary Islands. Cooper's flight was delayed for 24 hours due to a malfunction in the Bermuda FPS-16 radar's antenna data system. The radar set failed a CADFISS test, where all the stations in the network had to transmit information to NASA to ensure accurate information could be obtained. The failed part was replaced within 3 hours, but when the Capsule communicator asked for a realistic estimate, he was told 24 hours. The mission was immediately scrubbed for one day.
The network expanded for Project Gemini's longer flights which included rendezvous operations involving two spacecraft. A move toward increased computerization and decreased voice support for Gemini made a more centralized network possible with fewer primary stations and more secondary stations, although those major facilities were better equipped. Some Mercury stations were dropped; many were supplemented with new hardware. [5]
Gemini Network sites: [5]
The Manned Space Flight Network (MSFN) during the Apollo era was also known as the Apollo Network. From a NASA technical report on the history of the MSFN: [6]
The technical facts of life were these: the radars of the Mercury and Gemini Networks obviously could not track two spacecraft orbiting the Moon a quarter-million miles away: neither could the small MSFN telemetry antennas hope to pick out the telemetry and voice messages in the weak signals arriving from the vicinity of the Moon. Translated into network hardware terms, Apollo would require at least the following changes in the MSFN:
- A range and range rate tracking system, such as GRARR or the JPL range and range rate system, would have to be incorporated to accurately track the distant spacecraft while it was out of radar range.
- Large dish antennas with high gains, such as the 26-m paraboloids employed in STADAN and the DSN, would have to be added to the MSFN to track and communicate at lunar distances.
- Extant MSFN stations could not properly monitor the very critical mission phases when the spacecraft was inserted into its lunar trajectory and when it plunged into the narrow reentry corridor on the return trip. The result was that the MSFN had to be extended with ships, aircraft, and additional land sites.
- Small paraboloidal antennas would have to be added at some MSFN sites to communicate with the Apollo spacecraft while it was still below the horizon for the 26-m dishes (below about 16,000 km) but beyond the range of the Gemini telemetry antennas.
- The communication traffic during the Apollo missions would be several times that planned for Gemini. NASCOM lines would have to be augmented.
To meet these requirements, the MSFN used a combination of resources. A Jet Propulsion Laboratory (JPL) system called "Unified S-band", or USB, was selected for Apollo communications, which allowed tracking, ranging, telemetry, and voice to all use the same S band transmitter. Near-Earth tracking was provided by upgrading the same networks used for Mercury and Gemini. New large antennas for the lunar phase were constructed explicitly for the MSFN, with Deep Space Network (DSN) large antennas used for backup and critical mission phases.
Although normally tasked with tracking uncrewed spacecraft, the Deep Space Network (DSN) also contributed to the communication and tracking of Apollo missions to the Moon, [7] although primary responsibility remained with the Manned Space Flight Network (MSFN). The DSN designed the MSFN stations for lunar communication and provided a second antenna at each MSFN site (the MSFN sites were near the DSN sites for just this reason). Two antennas at each site were needed since the beam widths which the large antennas required were too small to encompass both the lunar orbiter and the lander at the same time. DSN also supplied some larger antennas as needed, in particular for television broadcasts from the Moon, and emergency communications such as Apollo 13. [1]
From a NASA report describing how the DSN and MSFN cooperated for Apollo: [6]
Another critical step in the evolution of the Apollo Network came in 1965 with the advent of the DSN Wing concept. Originally, the participation of DSN 26-m antennas during an Apollo Mission was to be limited to a backup role. This was one reason why the MSFN 26-m sites were collocated with the DSN sites at Goldstone, Madrid, and Canberra. However, the presence of two, well-separated spacecraft during lunar operations stimulated the rethinking of the tracking and communication problem. One thought was to add a dual S-band RF system to each of the three 26-m MSGN antennas, leaving the nearby DSN 26-m antennas still in a backup role. Calculations showed, though, that a 26-m antenna pattern centered on the landed Lunar Module would suffer a 9-to-12 db loss at the lunar horizon, making tracking and data acquisition of the orbiting Command Service Module difficult, perhaps impossible. It made sense to use both the MSFN and DSN antennas simultaneously during the all-important lunar operations. JPL was naturally reluctant to compromise the objectives of its many unmanned spacecraft by turning three of its DSN stations over to the MSFN for long periods. How could the goals of both Apollo and deep space exploration be achieved without building a third 26-m antenna at each of the three sites or undercutting planetary science missions?
The solution came in early 1965 at a meeting at NASA Headquarters, when Eberhardt Rechtin suggested what is now known as the "wing concept". The wing approach involves constructing a new section or "wing" to the main building at each of the three involved DSN sites. The wing would include a MSFN control room and the necessary interface equipment to accomplish the following: 1. Permit tracking and two-way data transfer with either spacecraft during lunar operations. 2. Permit tracking and two-way data transfer with the combined spacecraft during the flight to the Moon 3. Provide backup for the collocated MSFN site passive track (spacecraft to ground RF links) of the Apollo spacecraft during trans-lunar and trans-earth phases. With this arrangement, the DSN station could be quickly switched from a deep-space mission to Apollo and back again. GSFC personnel would operate the MSFN equipment completely independently of DSN personnel. Deep space missions would not be compromised nearly as much as if the entire station's equipment and personnel were turned over to Apollo for several weeks.
The details of this cooperation and operation are available in a two-volume technical report from JPL. [8] [9]
As of February 20,2010 [update] , three different NASA networks are used - the Deep Space Network (DSN), the Near Earth Network (NEN) and the Space Network/Tracking and Data Relay Satellite System (TDRSS). The DSN, as the name implies, tracks probes in deep space (more than 10,000 miles (16,000 km) from Earth), while NEN and TDRSS are used to communicate with satellites in low earth orbit. TDRSS uses a network of 10 geostationary communication satellites, and a single ground station at White Sands Test Facility. [1]
After Apollo, the MSFN no longer needed the large antennas that had been used for lunar communication, which were eventually given over to the DSN. In 1985, the antenna at Honeysuckle Creek Tracking Station was moved to the Canberra Deep Space Communication Complex (CDSCC) DSN site, and the antenna at Fresnedillas was moved to the existing Robledo DSN location. The Goldstone Deep Space Communications Complex antenna is still in its original location. [7]
The NASA Deep Space Network (DSN) is a worldwide network of spacecraft communication ground segment facilities, located in the United States (California), Spain (Madrid), and Australia (Canberra), that supports NASA's interplanetary spacecraft missions. It also performs radio and radar astronomy observations for the exploration of the Solar System and the universe, and supports selected Earth-orbiting missions. DSN is part of the NASA Jet Propulsion Laboratory (JPL).
STS-43, the ninth mission for Space Shuttle Atlantis, was a nine-day mission whose primary goal was launching the TDRS-E satellite (TDRS-5). The flight also tested an advanced heatpipe radiator for potential use on the then-future space station and conducted a variety of medical and materials science investigations.
The U.S. Tracking and Data Relay Satellite System (TDRSS) is a network of American communications satellites and ground stations used by NASA for space communications. The system was designed to replace an existing network of ground stations that had supported all of NASA's crewed flight missions. The prime design goal was to increase the time spacecraft were in communication with the ground and improve the amount of data that could be transferred. Many Tracking and Data Relay Satellites were launched in the 1980s and 1990s with the Space Shuttle and made use of the Inertial Upper Stage, a two-stage solid rocket booster developed for the shuttle. Other TDRS were launched by Atlas IIa and Atlas V rockets.
A space capsule is a spacecraft designed to transport cargo, scientific experiments, and/or astronauts to and from space. Capsules are distinguished from other spacecraft by the ability to survive reentry and return a payload to the Earth's surface from orbit or sub-orbit, and are distinguished from other types of recoverable spacecraft by their blunt shape, not having wings and often containing little fuel other than what is necessary for a safe return. Capsule-based crewed spacecraft such as Soyuz or Orion are often supported by a service or adapter module, and sometimes augmented with an extra module for extended space operations. Capsules make up the majority of crewed spacecraft designs, although one crewed spaceplane, the Space Shuttle, has flown in orbit.
The Canberra Deep Space Communication Complex (CDSCC) is a satellite communication station, part of the Deep Space Network of NASA's Jet Propulsion Laboratory (JPL), located at Tidbinbilla in the Australian Capital Territory. Opened in 1965, the complex was used for tracking the Apollo Lunar Module, and along with its two sister stations at Goldstone, California and Madrid, Spain is now used for tracking and communicating with NASA's spacecraft, particularly interplanetary missions. Its DSS-43 antenna is the only antenna on Earth that can send commands to Voyager 2. It is managed in Australia by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) for NASA’s Space Communications and Navigation program (SCaN) at NASA Headquarters in Washington, D.C.
A tracking and data relay satellite (TDRS) is a type of communications satellite that forms part of the Tracking and Data Relay Satellite System (TDRSS) used by NASA and other United States government agencies for communications to and from independent "User Platforms" such as satellites, balloons, aircraft, the International Space Station, and remote bases like the Amundsen-Scott South Pole Station. This system was designed to replace an existing worldwide network of ground stations that had supported all of NASA's crewed flight missions and uncrewed satellites in low-Earth orbits. The primary system design goal was to increase the amount of time that these spacecraft were in communication with the ground and improve the amount of data that could be transferred. These TDRSS satellites are all designed and built to be launched to and function in geosynchronous orbit, 35,786 km (22,236 mi) above the surface of the Earth.
The Spacecraft Tracking and Data (Acquisition) Network was established by NASA in the early 1960s to satisfy the requirement for long-duration, highly available space-to-ground communications. The network was the “follow-on” to the earlier Minitrack, which tracked the flights of Sputnik, Vanguard, Explorer, and other early space efforts (1957–1962). Real-time operational control and scheduling of the network was provided by the Network Operations Control Center (NOCC) at the Goddard Space Flight Center (GSFC) in Greenbelt, Maryland.
The Madrid Deep Space Communications Complex (MDSCC), in Spanish and officially Complejo de Comunicaciones de Espacio Profundo de Madrid, is a satellite ground station located in Robledo de Chavela, Spain, and operated by the Instituto Nacional de Técnica Aeroespacial (INTA). Part of the Deep Space Network (DSN) of NASA's Jet Propulsion Laboratory (JPL), along with its two sister stations at Goldstone, California and Canberra, Australia it is used for tracking and communicating with NASA's spacecraft, particularly interplanetary missions. The DSN and the Near Space Network (NSN) are services of the NASA Space Communications and Navigation program (SCaN).
Maspalomas Station is an INTA-operated, ESTRACK radio antenna ground station for communication with spacecraft located at the southern area of Gran Canaria island, on the INTA campus. It is situated on the Montaña Blanca hill and is visible from the coastal resort of Meloneras, close to Maspalomas. It was originally established in the 1960s to support NASA's nascent human spaceflight program.
The Orroral Valley tracking station was an Earth station in Australia, supported Earth-orbiting satellites, as part of NASA's Spacecraft Tracking and Data Acquisition Network (STADAN). It was located approximately 50 km south of Canberra, Australian Capital Territory (ACT), and was one of three tracking stations in the ACT, and seven in Australia.
The Minitrack Network was the first U.S. satellite tracking network to become operational, in 1957. It was used to track the flights of Sputnik, Vanguard, Explorer, and other early space efforts. Minitrack was the progenitor of Spacecraft Tracking and Data Acquisition Network (STADAN) and the Manned Space Flight Network (MSFN).
Goddard Space Flight Center is NASA's first, and oldest, space center. It is named after Robert H. Goddard, the father of modern rocketry. Throughout its history, the center has managed, developed, and operated many notable missions, including the Cosmic Background Explorer, the Hubble Space Telescope, the Tracking and Data Relay Satellite System (TDRSS), the Lunar Reconnaissance Orbiter, and the Solar Dynamics Observatory.
Advanced Gemini is a number of proposals that would have extended the Gemini program by the addition of various missions, including crewed low Earth orbit, circumlunar and lunar landing missions. Gemini was the second crewed spaceflight program operated by NASA, and consisted of a two-seat spacecraft capable of maneuvering in orbit, docking with uncrewed spacecraft such as Agena Target Vehicles, and allowing the crew to perform tethered extra-vehicular activities.
The Merritt Island Spaceflight Tracking and Data Network station, known in NASA parlance as MILA, was a radio communications and spacecraft tracking complex located on 61 acres (0.25 km2) at the Kennedy Space Center (KSC) in Florida. The name MILA was an acronym for the "Merritt Island Launch Annex" to Cape Canaveral Air Force Station, which was how the site was referred to when spacecraft launches were primarily originating from the adjacent military installation. MILA's arrays of antennas provided various communications and data services between spacecraft and NASA centers, as well as tracked and ranged moving spacecraft. In its final years, it served as the primary voice and data link during the first 7½ minutes of Space Shuttle launches, and the final 13 minutes of shuttle landings at KSC. Though it occupied land at KSC, MILA was operated and managed by the Goddard Space Flight Center.
The NASA (Ground) Communications System (NASCOM) manages terrestrial communications between ground stations, mission control centers, and other elements of spacecraft ground segments. Established in 1964, NASCOM provides worldwide, near real-time, transmission of commands, telemetry, voice, and television signals. It is managed out of NASA's Goddard Space Flight Center in Greenbelt, Maryland.
The Unified S-band (USB) system is a tracking and communication system developed for the Apollo program by NASA and the Jet Propulsion Laboratory (JPL). It operated in the S band portion of the microwave spectrum, unifying voice communications, television, telemetry, command, tracking and ranging into a single system to save size and weight and simplify operations. The USB ground network was managed by the Goddard Space Flight Center (GSFC). Commercial contractors included Collins Radio, Blaw-Knox, Motorola and Energy Systems.
Tecwyn Roberts was a Welsh spaceflight engineer who in the 1960s played important roles in designing the Mission Control Center at NASA's Johnson Space Center in Houston, Texas and creating NASA's worldwide tracking and communications network.
There are NASA facilities across the United States and around the world. NASA Headquarters in Washington, DC provides overall guidance and political leadership to the agency. There are 10 NASA field centers, which provide leadership for and execution of NASA's work. All other facilities fall under the leadership of at least one of these field centers. Some facilities serve more than one application for historic or administrative reasons. NASA has used or supported various observatories and telescopes, and an example of this is the NASA Infrared Telescope Facility. In 2013 a NASA Office of the Inspector General's (OIG) Report recommended a Base Realignment and Closure Commission (BRAC) style organization to consolidate NASA's little used facilities. The OIG determined at least 33 of NASA's 155 facilities were underutilized.
The forerunner of the Deep Space Network was established in January 1958, when JPL, then under contract to the U.S. Army, deployed portable radio tracking stations in Nigeria, Singapore, and California to receive telemetry and plot the orbit of the Army-launched Explorer 1, the first successful U.S. satellite.
The Deep Space Atomic Clock (DSAC) was a miniaturized, ultra-precise mercury-ion atomic clock for precise radio navigation in deep space. DSAC was designed to be orders of magnitude more stable than existing navigation clocks, with a drift of no more than 1 nanosecond in 10 days. It is expected that a DSAC would incur no more than 1 microsecond of error in 10 years of operations. Data from DSAC is expected to improve the precision of deep space navigation, and enable more efficient use of tracking networks. The project was managed by NASA's Jet Propulsion Laboratory and it was deployed as part of the U.S. Air Force's Space Test Program 2 (STP-2) mission aboard a SpaceX Falcon Heavy rocket on 25 June 2019.