- The new 66-foot-wide antennas will be built, online and operational in time to provide near-continuous communications service to Artemis astronauts on the moon later this decade.
- The antennas, called LEGS, short for Lunar Exploration Ground Sites, represent critical infrastructure for NASA’s vision of supporting a permanent human presence on the Moon.
- The first three of the six proposed LEGS are planned for sites in New Mexico, South Africa and Australia.
- LEGS will become part of NASA’s Near Space Network, managed by the agency’s Space Communications and Navigation (SCaN) program and run from the Goddard Space Flight Center in Greenbelt, Maryland.
NASA’s LEGS can do more than just help Earthlings navigate the planet.
The three lunar Exploration Ground Sites, or LEGS, will enhance Near Space Network communications services and support for NASA’s Artemis campaign.
NASA’s Space Communications and Navigation (SCaN) program manages the agency’s two primary communications networks—the Deep Space Network and the Near Space Network—that allow satellites in space to send data back to Earth for investigation and discovery.
Using antennas around the world, these networks pick up signals from satellites, collect data and allow navigation engineers to track the mission. For the first Artemis mission, these networks worked in tandem to support the mission as it completed its 25-day journey around the Moon. They will do the same for the upcoming Artemis II mission.
In support of NASA’s Moon to Mars initiative, NASA is adding three new LEGS antennas to the Near Space Network. As NASA works to maintain a human presence on the Moon, communications and navigational support will be critical to the success of any mission. The LEGS antennas will directly support later Artemis missions and companion missions such as the Human Landing System, Lunar Terrain Vehicle and Gateway.
“One of the main goals of LEGS is to land the Deep Space Network,” said TJ Crooks, LEGS project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The Near Space Network and its new LEGS antennas will focus on lunar missions while enabling the Deep Space Network to support missions further into the solar system – such as the James Webb Space Telescope and the Voyager interstellar missions.”
The Near Space Network provides communications and navigation services to missions anywhere within 1.2 million miles of Earth—this includes the Moon and Sun-Earth Lagrange Points 1 and 2. The Moon and Lagrange Points are a shared area with the Deep Space Network that can provide service missions there and beyond in the solar system.
The LEGS antennas, which are 66 feet in diameter, will be strategically placed around the world. This global placement ensures that when the Moon sets in one station, it rises in view of another. With the Moon in sight at all times, the Near Space Network will be able to provide continuous support to lunar operations.
As the satellite orbits the moon, it encodes its data into a high-frequency signal. When a LEGS antenna comes up, that satellite (or rover, etc.) will beam down to the LEGS antenna. This data is then routed to mission operators and scientists around the world, who can make decisions about the health and orbit of the spacecraft or use the science data to make discoveries.
LEGS antennas are intended to be extremely flexible for the user. For LEGS-1, LEGS-2, and LEGS-3, NASA is implementing a “dual-band approach” for antennas that will allow the missions to communicate using two different radio frequency bands—X-band and Ka-band. Smaller data packets – such as telemetry data – are typically sent in X-band, while scientific data or high-resolution images require Ka-band. With its higher frequency, Ka-band allows significantly more information to be downloaded at once, such as real-time high-definition video to support manned operations.
Additional LEGS capacity will be requested from commercial service providers and will include “tri-band access” for antennas using S-band in addition to X- and Ka-band.
The first LEGS ground station, or LEGS-1, is at NASA’s White Sands Complex in Las Cruces, New Mexico. NASA is upgrading the grounds and facilities at the complex to accommodate the new LEGS-1 antenna.
The LEGS-2 antenna will be in Matjiesfontein, South Africa, near Cape Town. Working with SANSA, South Africa’s National Space Agency, NASA chose this location to maximize lunar coverage. South Africa was home to a ground tracking station near Johannesburg that played a role in NASA’s Apollo missions to the moon in the 1960s. The agency plans to complete the LEGS-2 antenna in 2026. For LEGS-3, NASA is exploring sites in Western Australia.
These stations will fully complement the existing capabilities of the Near and Deep Space Networks and enable more robust communication services for the Artemis campaign.
The Near Space Network is funded by NASA’s Space Communications and Navigation (SCaN) program office at NASA Headquarters in Washington and operated by NASA’s Goddard Space Flight Center in Greenbelt, Maryland.