Cold Atom Interferometry One Step Closer to Orbit

An activity from the European Space Agency’s General Support Technology Programme is changing that by developing critical components for a future cold atom interferometer.

“It's called CAIVAS, (Cold Atom Interferometer VAcuum System) and is one of the first elements of the full instrument. It will produce the quantum object, a cold gas of atoms, that we can cool down with lasers,” explains Olivier Carraz, the ESA Technical engineer in charge of the project

Cold atom interferometers have traditionally been bulky, power-hungry and designed for laboratory conditions. CAIVAS is part of the effort to make the technology more compact and robust so it can survive the harsh environment of space. CAIVAS builds on work done in this area of quantum technology for more than a decade.

“I would say, since I've been at ESA, the last 10, 15 years, we have been pushing a lot of development for all the different subsystem, to reach maturity,” says Olivier. “We needed them to be more compact, more robust, more reliable, et cetera, for them to be considered for any space application.”

Cold-atom sensors rely on the properties of atoms and can, in principle, provide an absolute measurement without the regular calibration required by conventional instruments.

Rather than tackling the entire instrument at once, the team behind CAIVAS tackled one area – a simplified atom-chip vacuum system needed to isolate and manipulate cold atoms. They then successfully tested the key technologies in a thermal-vacuum range of −20°C to +55°C, including the vacuum seals, electrical structures, optical coatings, pump and a pressure gauge.

“You have a laser system with the laser going through it, and in the middle you have this gas of atoms, which you trap with the laser and magnetic fields, you cool them and then you do the measurement at a later stage,” Olivier says, pointing to each part of the system on the image.

The results provide valuable insight into how the vacuum system and its components behave across different temperatures, helping engineers refine requirements and reduce uncertainty for future missions.

Most importantly, CAIVAS showed that cold-atom hardware can begin to be industrialised. For Olivier, the significance is that technology normally associated with specialist laboratory experiments was successfully built and tested through an industrial process. Full operational applications may still be some way off, but the work demonstrates that putting this kind of technology in space is becoming more realistic.

Next, other ESA activities continue to develop the lasers, magnetic shielding and other elements to bring the complete instrument together and lessons from the testing will feed into more advanced hardware until a qualification model can be built.