September 26, 2024 -- An new project, launched by the European Commission and supported by the Quantum Flagship, is set to transform the way in which Earth monitoring is conducted by providing more accurate data on changes in ice melt, groundwater depletion, and ocean circulation.

CARIOQA-PMP is a new €17 million project that seeks to improve traditional gravity-sensing methods by incorporating the capabilities of quantum sensors.

Materials on the Earth, whether rocks, minerals or water, have different densities from place to place and the Earth’s gravity field is affected by the mass of these materials. The more mass in an area, the stronger the gravitational pull in a particular spot. When large masses move or change, such as ice melting and flowing into the ocean, or when groundwater is depleted, it changes the local gravity.

Traditional gravity mapping can detect these differences, which can inform observers where underground water might be or how much ice is melting in the polar regions, or even help in finding natural resources. However, looking at the Earth from outer space, the picture of gravity is somewhat unclear. While very advanced, traditional gravimeters struggle with weak gravitational signals from Earth when trying to measure fine-scale variations across different regions.

Using quantum accelerometers, it will be possible to enhance capabilities using quantum physics. This tool will enable scientists to see a complete gravity map of the Earth in a much ‘higher resolution’.

Christine Fallet, project coordinator of CARIOQA-PMP, said, “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 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.”

The CARIOQA quantum technology is still in development, with the team employing a technique called Cold Atom Interferometry (CAI). CAI relies on the principles of quantum mechanics to examine and exploit the wave-like behaviour of atoms at extremely low temperatures.

When atoms are cooled to near absolute zero, they move almost in slow motion, allowing for extremely precise measurements with lasers. “When cooled,” Fallet said, “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.”

“Cold Atom Interferometry avoids some problems of older systems, producing clearer, more reliable data over time. When it comes to measuring gravity, CAI is like upgrading from a blurry old TV to a crystal-clear HD screen. This technology will give us a much sharper view of what’s happening to our planet.”

The project comes in two parallel parts: CARIOQA-PMP (‘Pathfinder Mission Preparation’ is focused on developing quantum accelerometry technology for use in space within the next decade. This project will lay the groundwork for the Quantum Pathfinder Mission, with CARIOQA-PHA continuing the effort to demonstrate the feasibility of a Quantum Space Gravimetry Pathfinder Mission, aiming to enable the deployment of quantum gravimeters and accelerometers in space by the European Union.

CARIOQA brings together a consortium of key partners, including the French Space Agency (Centre National d’etudes Spatiales – CNES), the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt e.V. – DLR), industrials (Airbus Defence and Space in both France and Germany (ADS-F, ADS-G), EXAIL, TELETEL, LEONARDO, GMV), European laboratories and universities (LUH, SYRTE, LP2N, LCAR, ONERA, FORTH, TUM, POLIMI, DTU), and expert in impact maximisation (FORTH/PRAXI, groupe GAC).