A small receiver designed by NASA will soon test the use of GPS and Galileo signals near the Moon. Named NavCube3-mini, the device was delivered to Intuitive Machines on July 13, 2026. It will be integrated into the Altus-1 relay satellite, intended for future lunar missions.
The unit is about half the size of a shoebox and weighs 1.6 kg. Its power consumption remains below 20 W, roughly equivalent to that of a lightly used laptop. Despite its compact size, it must calculate a satellite’s position well beyond the usual Earth orbits.
Earth sets over the Moon’s curved limb on April 6, 2026, photographed by the Artemis 2 astronauts during their journey around the far side.
Credit: NASA
The American GPS and its European equivalent, Galileo, mainly broadcast their signals toward Earth. However, a small portion of these waves extends beyond the edge of our planet and continues into space. Highly sensitive receivers can detect them at great distances and combine several measurements to determine a position.
NavCube3-mini is set to fly aboard Altus-1, the first element of a commercial relay satellite network planned by Intuitive Machines. These spacecraft are intended to transmit communications and provide navigation services around the Moon. Their role would be particularly useful near the South Pole, where the terrain can directly block the view of Earth.
Before delivery, the receiver underwent several series of tests at NASA’s Goddard Space Flight Center. Engineers reproduced launch vibrations, the vacuum of space, and major temperature variations. They also verified that the electronics would not interfere with the satellite’s other equipment.
Prototype GPS/Galileo receiver for the Moon
Performance was checked before and after each test using accurate simulations of the GPS and Galileo signals expected in lunar orbit. These tests demonstrate the system’s operation on the ground under the reproduced conditions. The mission will still need to confirm the device’s actual performance near the Moon.
This demonstration could reduce lunar spacecraft’s dependence on calculations performed from Earth. A position obtained directly on board would make maneuvers easier and improve coordination among orbiters, landers, and rovers. Altus-1 must now receive the receiver before final system checks and launch preparations.