Quantum space sensor to fight climate change

The European Commission has launched an ambitious new project, backed by the Quantum Flagship, which is set to revolutionise Earth monitoring. This project will deliver more accurate data on ice melt, groundwater depletion, and ocean circulation, allowing scientists to track climate changes with greater urgency and precision.

Named CARIOQA-PMP, the €17million project aims to enhance traditional gravity-sensing methods by leveraging the extraordinary potential of quantum sensors. The Earth's gravity field is influenced by varying densities of materials, such as rocks, minerals, and water. When masses shift or change – like ice melting into the ocean or groundwater depletion – these movements alter the local gravitational pull.

Current gravity mapping technologies can detect these shifts, helping us locate underground water, assess ice melt in polar regions, and even discover natural resources. However, traditional gravimeters face challenges when measuring subtle gravitational signals, particularly when observing fine-scale variations from space.

CARIOQA-PMP is set to address these limitations. The project’s quantum accelerometer will be the first of its kind to apply quantum physics, offering scientists a higher-resolution gravity map of Earth.

Christine Fallet, Project Coordinator for CARIOQA-PMP, explained: “Traditional gravimeters, or classical electrostatic accelerometers, have some limitations in sensitivity and precision. However, they provide information that allows us to detect major ocean currents from Earth; smaller or more subtle features might not be captured with enough detail or be missed completely. This is not satisfactory for accurate Earth monitoring and studying the smallest changes in gravity caused by subtle shifts like small amounts of ice melting or minor groundwater depletion.

“The goal of the CARIOQA project is to develop groundbreaking quantum space-borne accelerometer technologies that can transform satellite-based Earth science. These advancements are set to play a pivotal role in monitoring climate change and supporting global efforts in developing mitigation and adaptation strategies.”

A new frontier in precision measurement

CARIOQA’s quantum technology, while still under development, is built on a technique called Cold Atom Interferometry (CAI). This method utilises quantum mechanics to study the wave-like behaviour of atoms at extremely low temperatures. By cooling atoms to near absolute zero, their movements slow, enabling precise measurements using lasers.

“When cooled,” Fallet noted, “the atoms’ wave-like nature can be exploited to create interference patterns (similar to ripples in water overlapping). By analysing these patterns, we can measure the atoms’ acceleration with great precision.”

CAI improves upon older systems by producing clearer, more reliable data over extended periods. As Fallet described, when measuring gravity, CAI offers an upgrade similar to transitioning from a blurry TV to a crystal-clear HD display, providing a much sharper view of the planet's changes.

Pioneering European leadership in quantum space technology

The CARIOQA project operates in two phases. The first, CARIOQA-PMP (Pathfinder Mission Preparation), focuses on developing quantum accelerometry for space applications over the next decade. This initiative lays the groundwork for the Quantum Pathfinder Mission, while the second phase, CARIOQA-PHA, aims to demonstrate the feasibility of deploying quantum gravimeters and accelerometers in space. These efforts are set to enable a Quantum Space Gravimetry Pathfinder Mission by the European Union.

“This undertaking aims to provide a powerful tool for Earth observation. It is a critical step for the European Union to establish itself as a leader in quantum space technology. The success of CARIOQA could position Europe at the forefront of global efforts to combat climate change while simultaneously showcasing the power of quantum technology in addressing one of the most pressing challenges of our time,” Fallet stated.

The CARIOQA project is a collaboration between several key partners, including the French Space Agency (CNES), the German Aerospace Centre (DLR), industrial partners (Airbus Defence and Space in France and Germany, EXAIL, TELETEL, LEONARDO, GMV), and European laboratories and universities (LUH, SYRTE, LP2N, LCAR, ONERA, FORTH, TUM, POLIMI, DTU). The project also benefits from the expertise of FORTH/PRAXI and the GAC group in maximising its impact.