BECCAL – developing technologies for quantum sensors in space

In doing so, researchers are laying the foundations for fundamental research and the development of future quantum sensors. Essentially, the goal is to generate a Bose-Einstein condensate from an atomic cloud and observe it in microgravity, allowing external disruptive forces to be measured with incredible precision. The ISS provides a unique continuous free fall environment, allowing for extended microgravity conditions and observation times, the use of additional trap configurations for capturing and cooling atoms and enhanced experimental repeatability – essential for collecting consistent data and performing reliable statistical analyses.

Cold atoms for sensors and communication

Cold atoms exist close to absolute zero, at approximately minus 273 degrees Celsius, and their properties offer new insights into quantum physics. The BECCAL experiment, developed jointly by DLR and NASA, has been designed to study precisely this.

A prominent example of a quantum experiment is the investigation into free fall – the state of a body that moves freely only under the influence of gravity. In a vacuum, all objects – no matter their size or mass – fall at the same speed. The principle was famously demonstrated during the Apollo 15 mission to the Moon by American astronaut David Scott, who dropped a hammer and a feather at the same time, each landing on the lunar surface simultaneously. With a Bose-Einstein condensate, this principle can now be investigated with the utmost precision. To do this, two different types of atoms – in this case rubidium and potassium – are cooled and their acceleration in Earth's gravity is measured. In addition to this specific experiment, BECCAL is intended to enable a wide range of research on and with cold atoms.

Researchers worldwide will be able to experiment with Bose-Einstein condensates in microgravity. One aim is to use them in quantum sensors, with applications ranging from Earth observation, satellite navigation and quantum communication to testing fundamental theories such as general relativity.

BECCAL is based on QUANTUS and MAIUS, a series of DLR-funded projects for atomic optics experiments in microgravity – conducted in the drop tower in Bremen and on sounding rockets. The project also draws on the experience of the Cold Atom Laboratory (CAL), which was developed at NASA's Jet Propulsion Laboratory in California (Caltech) and installed on the ISS in 2018.