The US military’s X-37B orbital test vehicle is set to embark on its eighth mission into space on August 21, 2025. While much of the spaceplane’s activities remain classified, it serves as a platform for pioneering experiments. Among these is a groundbreaking test of a quantum inertial sensor, which could potentially revolutionize navigation by providing an alternative to GPS.
Satellite-based systems like GPS are integral to modern life, facilitating everything from smartphone navigation to aviation and logistics. However, GPS signals can be unreliable or unavailable in certain environments, such as deep space, underwater, or in conflict zones where signals may be jammed or spoofed. The quantum inertial sensor aboard the X-37B aims to address these challenges by offering navigation capabilities independent of external signals.
Understanding the Quantum Advantage
Traditional inertial navigation systems (INS) rely on accelerometers and gyroscopes to track a vehicle’s movements. While they provide some level of independent navigation, they are prone to drift over time due to accumulating measurement errors, necessitating periodic corrections from GPS or other external references.
Quantum physics, often associated with the peculiar behavior of particles at microscopic scales, offers a solution. Atoms, when cooled to near absolute zero, exhibit wave-like properties and can exist in multiple states simultaneously. This forms the basis of quantum inertial sensors, which use a technique called atom interferometry.
In atom interferometry, atoms are split into superposition states, allowing them to travel along two paths simultaneously. These paths are then recombined, creating an interference pattern that encodes detailed information about the environment’s effects on the atoms’ journey. This enables the detection of minute shifts in motion with unprecedented sensitivity.
Compared to classical systems, quantum sensors offer orders of magnitude greater sensitivity, providing long-duration, high-accuracy navigation without external references.
Implications for Space and Military Operations
The upcoming X-37B mission marks the first instance of quantum inertial navigation being tested in space. Previous missions, like NASA’s Cold Atom Laboratory, have demonstrated atom interferometry in orbit but not specifically for navigation. The X-37B experiment aims to transition this technology from theoretical science to practical aerospace applications.
This advancement holds significant implications for both military and civilian spaceflight. For the US Space Force, it represents enhanced operational resilience in scenarios where GPS might be compromised. For future space exploration missions to the Moon, Mars, or beyond, a reliable quantum navigation system could serve as a primary or backup system when Earth-based signals are unavailable.
The Broader Quantum Technology Landscape
Quantum navigation is part of a larger wave of quantum technologies moving from laboratory research to real-world applications. While quantum computing and communication often capture headlines, quantum clocks and sensors are poised for widespread adoption.
Countries such as the US, China, and the UK are heavily investing in quantum inertial sensing. In 2024, Boeing and AOSense conducted the first in-flight quantum inertial navigation test aboard a crewed aircraft, demonstrating continuous GPS-free navigation for approximately four hours. The UK also conducted its first publicly acknowledged quantum navigation flight test on a commercial aircraft the same year.
This summer, the X-37B mission will extend these advances into space. Given its military nature, the test may remain under the radar, but its success could mark a pivotal moment in space navigation technology.
The announcement of the X-37B’s upcoming mission highlights the ongoing evolution of navigation technologies and the potential for quantum science to reshape our understanding of movement in challenging environments. As the world watches, this mission could indeed represent a quantum leap forward in space exploration.
