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The SCaN Networks

NASA’s space communications and navigation capabilities rest on two complementary networks that have evolved over seven decades to enable exploration from Earth orbit to the edge of interstellar space. Together, these networks form an integrated architecture that ensures continuous connectivity for missions from the International Space Station 250 miles above Earth to Voyager at the edge of the solar system.

Mars Antenna: The Big Antenna

History of the Networks

Some pieces of the SCaN (Space Communications and Navigation) Program are older than NASA itself. The Deep Space Network, managed by NASA’s Jet Propulsion Laboratory with antenna complexes in California, Spain, and Australia, tracks missions at the Moon and beyond. The Near Space Network, made up of global ground stations and satellite relay systems, supports spacecraft in low Earth and lunar orbits. These networks work together, handing off responsibilities across missions to keep spacecraft connected to Earth.

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A Visual History

Model of the Sputnik satellite on a black background — 1957: Before NASA existed, America was already watching the skies. The first U.S. satellite tracking system, the Minitrack Network, became operational just in time to monitor the world’s first artificial satellite: Sputnik.
A model of Sputnik hanging in Milestones of Flight, National Air and Space Museum.
Smithsonian Institution

A vintage JPL graphic celebrating the Explorer 1 satellite — 1958: The Jet Propulsion Laboratory set up portable tracking stations in Nigeria, Singapore, and California to follow signals from Explorer 1: America’s first satellite. It would be eight months before NASA was officially established.
America first satellite, Explorer 1. Built by NASA’s Jet Propulsion Laboratory, America joined the space race with the launch of this small, but important spacecraft.
NASA

Black-and-white photograph showing an astronaut being seated inside the Liberty Bell 7 Mercury spacecraft during preflight preparations, while two technicians in white caps and headsets assist at the open hatch. The capsule’s exterior is visible in the foreground with the hand-painted text “LIBERTY BELL 7” on its corrugated metal surface. — 1961: The United States formed a global web of communications antennas from 18 ground stations and two ships to maintain contact with America’s first astronauts as they orbited Earth at 17,500 miles per hour.
Astronaut Gus Grissom entering Mercury-Redstone Capsule, Liberty Bell 7, assisted by fellow astronaut John Glenn in anticipation of MR-4 mission launch on July 21, 1961.
NASA

An early Nimbus satellite undergoes vibration testing at NASA's Goddard Space Flight Center in Greenbelt, Maryland, circa 1967. — 1962: The Satellite Tracking and Data Acquisition Network (STADAN) expansion begins. NASA adds its first large dish antenna at Fairbanks, Alaska — a 26-meter parabolic dish that dramatically improved tracking capabilities.
The first 26-meter (85-foot) antenna for the Satellite Tracking and Data Acquisition Network (STADAN). This antenna in Fairbanks, Alaska was constructed to handle the overwhelming amount of data expected to come from the Nimbus program, one of NASA’s early meteorological satellites programs.
NASA

Black-and-white photograph of a NASA mission control room filled with rows of consoles, monitors, and control panels. Several engineers sit at their stations, while a large curved display wall spans the room above them, showing mission data, timelines, and imagery related to a spaceflight. — 1963: Ground stations around the world connected to the Jet Propulsion Laboratory’s new Space Flight Operations Facility, creating one unified Deep Space Network.
This archival photo, taken in 1964, shows engineers in Mission Control at NASA’s Jet Propulsion Laboratory.
NASA

Canberra complex — 1965: The Manned Space Flight Network control rooms are co-located near Deep Space Network sites, such as the Canberra complex on the Tidbinbilla Nature Reserve, enabling simultaneous tracking of Apollo’s spacecraft and lunar modules.
Located at Tidbinbilla Nature Reserve near the Australian capital city, the Canberra complex joined the Deep Space Network on March 19, 1965, with one 85-foot-wide (26-meter-wide) radio antenna.
NASA

Astronaut in a large white spacesuit stands on the Moon’s dark brown, dusty surface, leaning forward to place or adjust a slim scientific instrument in the ground. The sky beyond him is black and numerous boot prints in the lunar soil surround him. — 1969: The Apollo 11 moonwalk is broadcast around the world. Three stations received humanity’s first steps simultaneously. When Goldstone’s television feed experienced equipment challenges and the Moon rose higher in Australian skies, Houston controllers switched to video feed from the Honeysuckle Creek Tracking Station near Canberra and then to Parkes Observatory in New South Wales, combining their video broadcast with Goldstone audio to bring the world Neil Armstrong’s famous “giant leap for mankind.”
The Apollo 11 manned lunar mission launched from the Kennedy Space Center, Florida on July 16, 1969 via a Saturn V launch vehicle, and safely returned to Earth on July 24, 1969. The lunar module landed on the Moon’s surface on July 20, 1969 in the region known as Mare Tranquilitatis (the Sea of Tranquility). Astronaut Neil Armstrong was the first human to ever stand on the lunar surface.
NASA

Black-and-white photograph inside NASA’s Mission Control showing a group of flight controllers standing at their consoles and applauding. One man in the foreground raises his arm with a clenched fist in celebration, while others clap and smile around him. Control room consoles, papers, and monitors fill the foreground and background, capturing a moment of celebration. — 1970: After an explosion crippled the Apollo 13 spacecraft, the space communications engineers at Parkes Observatory in New South Wales, Australia reconfigured in roughly 12 hours — instead of the usual week — to help track the astronauts’ journey home.
The Mission Command Center at the moment of Apollo 13’s safe splashdown.
NASA

1975: During the joint American and Soviet Apollo-Soyuz human spaceflight, the first crewed international space mission, NASA’s ATS-6 satellite demonstrated space-based relay communications, boosting communications coverage from 15% to over 50%.

Astronaut Vance D. Brand, command module pilot of the American crew, is seen in the hatchway leading from the Apollo Command Module (CM) into the Apollo Docking Module (DM) during the joint U.S.-USSR Apollo-Soyuz Test Project docking mission in Earth orbit.

NASA

Composite view of the TDRS superimposed into Challenger Cargo Bay while on Pad 39A. — 1983: After its rocket failed, NASA engineers used tiny attitude thrusters to nudge the first Tracking and Data Relay Satellite (TDRS), TDRS-1, 8,600 miles higher to reach geostationary orbit. The successor to NASA’s Near Space network operated TDRS-1 for 26 years and majorly expanded space communications and navigation coverage.
Composite view of the the Tracking and Data Relay Satellite (TDRS) superimposed into the Challenger Cargo Bay while on Pad 39A.
NASA

This computer-generated montage created from images obtained by NASA Voyager 2 shows Neptune as it would appear from a spacecraft approaching Triton, Neptune largest moon at 2706 km 1683 mi in diameter. — 1987-1988: All three Deep Space Network dishes were expanded from 64 to 70 meters to maintain contact with Voyager 2 during its encounter with Neptune. At the time, Voyager 2 was 2.9 billion miles away from Earth.
This computer-generated montage created from images obtained by NASA Voyager 2 shows Neptune as it would appear from a spacecraft approaching Triton, Neptune largest moon at 2706 km 1683 mi in diameter.
NASA

This artist's concept drawing depicts the Tracking and Data Relay Satellite-C (TDRS-C), which was the primary payload of the Space Shuttle Discovery on the STS-26 mission, launched on September 29, 1988. The TDRS system provides almost uninterrupted communications with Earth-orbiting Shuttles and satellites, and had replaced the intermittent coverage provided by globe-encircling ground tracking stations used during the early space program. — 1989: With three satellites in position, the TDRS constellation expanded NASA’s space communications near-Earth coverage to 85%, a dramatic increase from the ground network’s 15%.
This artist’s concept depicts the TDRS-C, which was the primary payload of the Space Shuttle Discovery on the STS-26 mission, launched on September 29, 1988. The TDRS system provides almost uninterrupted communications with Earth-orbiting Shuttles and satellites, and had replaced the intermittent coverage provided by globe-encircling ground tracking stations used during the early space program.
NASA

July 1998 - Guam Remote Ground Terminal (GRGT) — 1998: The Guam Remote Ground Terminal began operations, closing the “Zone of Exclusion” coverage gap over the Indian Ocean and raising near Earth coverage to over 99%.
The Space Network’s Guam Remote Ground Terminal (GRGT).
NASA

The Lunar Reconnaissance Orbiter, shown in this artist's concept, carries seven instruments to explore the Moon's surface. — 2013: NASA uses optical or laser communications to beam an image of the Mona Lisa to the Lunar Reconnaissance Orbiter nearly 240,000 miles away. Since then, several laser communications demonstrations have proven the viability of using lasers to support the Near Space Network.
Artist rendering of the Lunar Reconnaissance Orbiter (LRO), above the Moon.
NASA

A computer screen in the mission support area shows Taters the cat in a still from the first high-definition streaming video to be sent via laser from deep space, as well as the incoming data stream delivering the frames from the video. — 2023: NASA’s Deep Space Optical Communications demonstration, piggybacking on NASA’s Psyche mission, sent data at 267 Megabits per second from 19 million miles from Earth, broadcasting an ultra-high-definition video of a cat named Taters. Lasers can transmit data at rates 10 to 100 times greater than the state-of-the-art radio frequency systems used by deep space missions today.
A computer screen in the mission support area shows Taters the cat in a still from the first ultra-high-definition streaming video to be sent via laser from deep space, as well as the incoming data stream delivering the frames from the video.
NASA

Kevin Coggins, Gregory Heckler, Joseph Downey, Stephen Creech, and Andrew Maynard discussing TDRS retirement and the Communications Services Project at the recent TDRS + CSP Townhall. — 2024: NASA announced the TDRS system would stop accepting new missions, beginning the transition to commercial providers.
Deputy Associate Administrator of SCaN Kevin Coggins, Deputy Program Manager for SCaN Capability Development Gregory Heckler, Project Lead Engineer for the Communications Services Project (CSP) Joseph Downey, Assistant Deputy Associate Administrator (Technical) for the Moon to Mars Program Stephen Creech, and the Science Mission Directorate’s Assistant Deputy Associated Administrator for Programs Andrew Maynard discussing TDRS retirement and the Communications Services Project at the 2025 TDRS + CSP Townhall at NASA Headquarters in Washington, D.C.
NASA

Three white, geodesic radomes stand on elevated platforms at the Troll Satellite Station in Antarctica. The radomes protect antennas positioned along a rocky, snowy ridge. The surrounding landscape features rugged terrain, distant mountains, and a bright sky, while a line of smiling KSAT employees line up on the staircase leading up to the antenna’s radome. The antenna in the foreground, TR9, was upgraded to support the Ka-band signal and a cloud storage system in preparation for SPHEREx. — 2025: Four private companies received contracts worth up to $4.82 billion to provide Near Space Network services through 2034. The transition to private services will allow space communications technology and services to evolve faster than ever before.
The Kongsberg Satellite Services’ upgraded ground station antenna at the Antarctic Troll Satellite Station allows NASA’s Near Space Network to support cloud-based space communications, enhancing its data support for modern missions.
Kongsberg Satellite Services

NASA’s Twin Networks

Pre-NASA Origins: Tracking the First Artificial Satellites

Even before NASA existed, America was building satellite tracking capabilities. The Minitrack Network, developed by the Naval Research Laboratory, began with a ground station in Blossom Point, Maryland and grew into ten ground stations stretching from Santiago, Chile to Grand Turk in the Turks and Caicos Islands. In 1957, the network tracked the Soviet Union's Sputnik, the world's first artificial satellite. The ground stations could only "see" Sputnik for a limited part of its orbit, and data moved at only 30 bits per second — about the speed of an early electromechanical typewriter called a teletype machine. When Explorer 1 launched on January 31, 1958, the Jet Propulsion Laboratory's portable tracking stations in Nigeria, Singapore, and California received signals eight months before NASA was officially established.

April 1986 - NTTF GSFC

Starting Small and Closing Gaps

Space communications systems have come a long way. NASA absorbed the Minitrack Network when it was officially established in 1958, and with it the principles that would guide NASA's communications for decades: global distribution of ground stations to maximize space coverage, redundancy for reliability, and international partnerships for worldwide reach. The Satellite Tracking and Data Acquisition Network (STADAN) replaced Minitrack in the early 1960s to support science and weather satellites, beginning with the construction of 26-meter dish antennas in Fairbanks, Alaska in May 1962.

Honeysuckle Creek, Australia

Building the Deep Space Network

Three Manned Space Flight Network stations handled communications during NASA's Moon missions: the Goldstone station in California's Mojave Desert, the Fresnedillas station near Madrid, and Honeysuckle Creek near Canberra, Australia. The Deep Space Network was established when the ground stations were connected to the Jet Propulsion Laboratory's Space Flight Operations Facility in 1963, creating one unified system dedicated to tracking spacecraft beyond Earth's orbit. All three main sites, built between 1958 and 1965, have made historic contributions to space exploration. Goldstone station's DSS-14, the 70-meter "Mars Antenna," has the world's only planetary radar system, and the station has supported missions from Mariner to the Perseverance Mars rover. The Manned Space Flight Network station at Fresnedillas de la Oliva, near Madrid, Spain, received Neil Armstrong's words: "Houston, Tranquility Base here. The Eagle has landed," and its DSS-56 was the first antenna that could handle all of the Deep Space Network's frequencies. Canberra's station handles about 42% of all deep space mission data, and its DSS-43 is the only antenna on Earth that can send commands to Voyager 2. After the Fresnedillas station closed in 1985, its antenna was relocated to the nearby Robledo de Chavela Complex, which today serves as NASA's Madrid Deep Space Communications Complex.

Black-and-white image displayed on a CRT monitor showing a grainy television transmission of Armstrong from the waist-up climbing down to the lunar surface, with parts of a ladder and spacecraft structure visible nearby. The image is framed by the monitor’s metal casing, emphasizing the low-resolution, historic broadcast quality.

Apollo 11: Watching History Through NASA's Networks

Human spaceflight required unprecedented communications capabilities. For near Earth missions, the Mercury Space Flight Network, completed in July 1961, included 18 ground stations and two naval ships to maintain contact with astronauts orbiting at 17,500 miles per hour. These resources were expanded into the Manned Space Flight Network during Gemini and Apollo to 29 ground stations and five tracking ships. The Unified S-Band system, first flown on Apollo 4 in 1967, combined tracking, ranging, telemetry, voice, command, and television into a single integrated system achieving ranging precision within 15 meters from 250,000 miles away. The innovation allowed controllers at the Manned Space Flight Network and Deep Space Network sites to simultaneously track both the Command Module orbiting the Moon and the Lunar Module on the surface. Both were essential to bringing astronauts Neil Armstrong, Buzz Aldrin, and Michael Collins home safely following their historic journey to the Moon.

NASA’s Voyager 1 spacecraft is depicted in this artist’s concept traveling through interstellar space, or the space between stars, which it entered in 2012.

Reaching the Ends of the Solar System

The three Deep Space Network antenna complexes are positioned 120 degrees apart around the globe to ensure spacecraft never lose contact with Earth as the planet rotates. Each complex now houses multiple antennas, including massive 70-meter dishes that can detect signals from billions of miles away. All three started with 64-meter dishes that were expanded to 70-meters in the 1980s to continue connecting with Voyager 2 as it flew past Neptune. The dish antennas weigh nearly 3,000 tons, float on thin films of oil like giant air hockey pucks, and are surface-accurate to within one centimeter across an area about two-thirds the size of a football field.

sts_6_tdrs_deployed_illustration

The Space Relay Revolution

By the 1970s, the limits of ground stations were becoming more noticeable. Ground stations could only see spacecraft in low Earth orbit about 15% of the time. As NASA and its partners across the world looked toward building a permanent space station, they needed much better coverage to keep Space Shuttle Program crews safe. NASA created the Tracking and Data Relay Satellite (TDRS) system to solve this problem: a series of satellites in geostationary orbit capable of seeing most of Earth at once. These first satellites would relay signals between spacecraft and a ground station at White Sands, New Mexico, boosting coverage from 15% to over 85%. The first satellite, TDRS-1, launched on Space Shuttle Challenger on April 4, 1983. Following a booster incident during Challenger's first flight that left the TDRS-1 stranded 8,600 miles below the correct orbit, engineers at NASA's Goddard Space Flight Center used the satellite's six small thrusters to move the stranded satellite higher in the air over the course of months. That single satellite provided more communications coverage for a Space Shuttle mission than the entire ground network had provided for all previous flights combined. The TDRS-1 kept NASA connected to its near Earth missions for 26 years — 16 years longer than planned.

The Near Space Network Grows

The Near Space Network is the most recent name for the NASA system that communicates with spacecraft within 1.25 million miles from Earth (about five times the distance to the Moon). This includes the International Space Station, the Hubble Space Telescope, Earth-observing satellites, and rockets during launch. The heart of today's Near Space Network is TDRS. Since the 1980s, three generations of TDRS satellites have launched, adding a new Ka-band radio capability capable of receiving more data, improved signal quality, and better error recovery. The last TDRS satellite, TDRS-13, was launched in 2017. Today, seven TDRS satellites continue operations, connecting to ground stations at White Sands Complex in New Mexico and the Guam Remote Ground Terminal, bringing near-Earth coverage to over 99%.

An artistic rendering of a circular ground station on Earth, shaded with shadows. The ground station sits in front of a row of shadowed pine trees and a bright night sky full of colorful stars. A red beam is shown transmitted from the ground station up to the upper right corner and out of frame, representing laser communications.

Communicating with Lasers and Beyond

As demand for space communications access grows, NASA is looking to lasers as a potential answer. Optical, or laser, communications — using infrared instead of radio waves — has the power to send data 10 to 100 times faster than radio signals using the same amount of power. Laser communications testing began in January 2013, when NASA beamed an image of the Mona Lisa to the Lunar Reconnaissance Orbit roughly 242,000 miles away. Since then, several laser communications demonstrations have proven the viability of using lasers to support the Near Space Network. In 2023, a laser communications test on the Psyche took the technology farther than ever. The results were amazing: Psyche streamed high-definition video at 267 megabits per second from 19 million miles away, and maintained 6.25 Mbps from 240 million miles away in 2024. As NASA to looks to providing internet-like capabilities at the Moon and beyond, laser communications will play an increasing role in space communications and navigation support.

What's Next: Private Partnerships and Looking to Mars

In November 2024, NASA announced that TDRS would stop accepting new missions and prepare for retirement in the 2030s. In December of that same year, NASA awarded contracts for new, private relay satellites to provide Near Space Network services through 2034 — with more opportunities to come. As demand for deep space communications grows, the Deep Space Network has begun to explore opportunities to work with commercial partners on new, enhanced ground stations. NASA will continue running the network for missions too far away for commercial services and foster the growth of communications and navigation technology in the private sector. The shift to commercial communications reflects NASA's strategic vision: focus agency resources on capabilities that don't exist yet commercially while partnering with industry to support the evolution of the invisible thread that connects Earth to the cosmos.

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SCaN
Quick Facts

The Value of Network Support
NASA’s networks have a long history and widespread applications across society. Explore our quick facts to learn about the unexpected and wide-reaching impact SCaN has on the history and future of space travel.

Quick Facts

The Near Space Network operates more than 40 government and commercially owned antennas across six continents, from Arctic facilities in Norway and Alaska, to equatorial stations in Singapore and Chile, to Antarctic stations at Troll and McMurdo. This pole-to-pole coverage ensures nearly uninterrupted contact with spacecraft regardless of their orbital position.

The Near Space Network operates more than 40 government and commercially owned antennas across six continents, from Arctic facilities in Norway and Alaska, to equatorial stations in Singapore and Chile, to Antarctic stations at Troll and McMurdo. This pole-to-pole coverage ensures nearly uninterrupted contact with spacecraft regardless of their orbital position.

The Deep Space Network’s 70-meter antennas can detect signals from Voyager 1, the most distant human-made object in space at more than 15 billion miles away. In November 2026, Voyager 1 will become the first human-made spacecraft to be one light-day away from Earth.

The Deep Space Network's 70-meter antennas can detect signals from Voyager 1, the most distant human-made object in space at more than 15 billion miles away. In November 2026, Voyager 1 will become the first human-made spacecraft to be one light-day away from Earth.

The TDRS satellites can transmit voice and data at very high rates. In optical conditions, a TDRS can transfer the equivalent of a 20-volume encyclopedia in only one second.

The TDRS satellites can transmit voice and data at very high rates. In optical conditions, a TDRS can transfer the equivalent of a 20-volume encyclopedia in only one second.

The Deep Space Network implemented antenna arraying for Voyager’s encounters with Uranus and Neptune, combining signals from multiple antennas across continents to effectively create one giant antenna receiver.

The Deep Space Network implemented antenna arraying for Voyager's encounters with Uranus and Neptune, combining signals from multiple antennas across continents to effectively create one giant antenna receiver.

The umbrella-like parabolic antennas on first generation TDRS are covered in 203 square feet of gold-plated mesh and measure over 16 feet in diameter, yet the entire system —including all deployment mechanisms—weigh only 53.5 pounds. This light weight was essential to meeting Space Shuttle payload constraints.

The umbrella-like parabolic antennas on first generation TDRS are covered in 203 square feet of gold-plated mesh and measure over 16 feet in diameter, yet the entire system —including all deployment mechanisms—weigh only 53.5 pounds. This light weight was essential to meeting Space Shuttle payload constraints.

The Deep Space Network’s planetary radar system in Goldstone, California fires a 500-kilowatt signal into space, or the equivalent of 5,000 light bulbs at once. This power allows NASA to bounce radar off asteroids and comets millions of miles away from Earth to determine their trajectories and assess potential threats, making it humanity’s primary tool for planetary defense radar observations.

The Deep Space Network's planetary radar system in Goldstone, California fires a 500-kilowatt signal into space, or the equivalent of 5,000 light bulbs at once. This power allows NASA to bounce radar off asteroids and comets millions of miles away from Earth to determine their trajectories and assess potential threats, making it humanity's primary tool for planetary defense radar observations.

Every antenna hour using SCaN networks is precious, with dozens of active missions competing for communications windows. NASA is adding new antennas in partnership with industry to address critical capacity needs for the Deep Space Network.

Every antenna hour using SCaN networks is precious, with dozens of active missions competing for communications windows. NASA is adding new antennas in partnership with industry to address critical capacity needs for the Deep Space Network.

Coverage handover between the Near Space Network and Deep Space Network occurs at approximately 22,000 miles above Earth.

Coverage handover between the Near Space Network and Deep Space Network occurs at approximately 22,000 miles above Earth.

Canberra, Australia’s DSS-43 is the largest steerable antenna in the Southern Hemisphere and operates the most powerful S-band transmitter in the entire Deep Space Network. At 400 kilowatts, it is 20 times more powerful than the standard transmitters at other stations and can reach spacecraft in interstellar space.

Canberra, Australia's DSS-43 is the largest steerable antenna in the Southern Hemisphere and operates the most powerful S-band transmitter in the entire Deep Space Network. At 400 kilowatts, it is 20 times more powerful than the standard transmitters at other stations and can reach spacecraft in interstellar space.

The SCaN Program is always exploring new ways to evolve communications technology. Optical or laser communications can transmit data at 10 to 100 times higher rates than radio frequency systems of the past —all while using smaller, lighter equipment.

The SCaN Program is always exploring new ways to evolve communications technology. Optical or laser communications can transmit data at 10 to 100 times higher rates than radio frequency systems of the past —all while using smaller, lighter equipment.

Featured Video

Modernizing for the Future

On May 2, 2025, NASA’s SCaN Program hosted the TDRS and Communications Services Project Townhall. Industry members, other government agencies, and mission teams came together for a hybrid event detailing the agency’s plan for retiring its legacy space relay fleet and embracing commercial companies.
The townhall covered the agency’s satellite relay commercialization strategy, provided status updates on key milestones in space communications, and outlined the retirement of NASA’s TDRS fleet.

Looking to the future

Commercial Space Communications

NASA’s SCaN Program is committed to a seamless transition from government-owned communications assets to commercial alternatives. Initiatives like the Communications Services Project and the Commercialization, Innovation, and Synergies office are ensuring the shift to commercial space communications continues to reflect the agency's commitment to excellence.

An artist's rendering of the Polylingual Experimental Terminal (PExt) floating above Earth. The terminal's dish antenna is facing right and with its blue-green solar panels extended in an X-formation behind it. In the background, the sun can be seen creating across the Eastern Hemisphere.

NASA’s SCaN Program is pioneering a new era of space communications by partnering with industry to provide commercial space relay communications services for NASA missions near Earth.

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