Leibniz University

Sounding rockets launched into space

On 2 December 2023 a research alliance, in which Leibniz University played a crucial role, launched the MAIUS-2 high-altitude research rocket into space. This mission’s purpose is to investigate ultracold quantum gases under zero gravity.

People pose next to a rocket labeled MAIUS 2. — The MAIUS team and the MAIUS-2 rocket at the Esrange Space Center.

At 8.30 a.m. CET on Saturday 2 December, a rocket was successfully blasted into space from the European Space and Sounding Rocket Range near Kiruna in Sweden. A high-altitude research vehicle called MAIUS-2, it was launched by a research alliance in which Leibniz University Hannover plays a leading role. During the flight, a period of around five and a half minutes was available for tests in zero-gravity conditions before the rocket fell back to Earth as planned. During this window, various experiments were performed – for the most part autonomously – on board the rocket. The launch had been preceded by months of meticulous preparation.

Quantum state: Bose-Einstein condensate

On this MAIUS-2 mission, the researchers’ aim was to generate mixtures of quantum gases from two different types of atom, and to explore and monitor their interactions under zero gravity. To this end, the objective was to cool atoms of rubidium and potassium down to temperatures as low as a few hundred nanokelvins, i.e. just above the theoretical absolute-zero point. The atoms then assume an extreme quantum state known as Bose-Einstein condensate. Production of these quantum gases requires a great deal of technological effort but nevertheless provides unique scope for research. Whereas it proved possible to demonstrate the generation of rubidium Bose-Einstein condensates and their behaviour in free fall, the Bose-Einstein condensate of potassium atoms did not form as intended. However, the MAIUS-2 flight still yielded valuable findings which will be evaluated in the coming months.

Scientists hope for deeper understanding of the fundamental forces of nature

Controlled generation of, and control of, Bose-Einstein condensates is the basic prerequisite for highly accurate measurement of acceleration and forces using tools called atomic interferometers. The investigators hope that applying this technology in space will provide greater understanding of the fundamental forces of nature. For example, the universality of free fall is to undergo future testing with the aid of atomic interferometry. And there are other uses for which space-based atomic interferometry is among the most promising approaches, including more precise, high-resolution measurement of the Earth’s gravitational field and navigation of future space probes. The MAIUS sounding rockets are opening up new frontiers and paving the way for a joint American-German lab – the Bose-Einstein Condensate and Cold Atom Laboratory (BECCAL) – for exploration of quantum gases on the International Space Station (ISS).

The technology works up in space – at least in principle

Even the preceding mission (MAIUS-1, back in 2017) was considered one of the most complex experiments ever flown on a sounding rocket. It marked the first time that researchers managed to generate a Bose-Einstein condensate in space. Because a second type of atom was now needed, the MAIUS-2 team had to accommodate twice the number of lasers in the rocket, along with electronic assemblies required to operate them. Technologically quite a challenge – since, despite the increased complexity of the payload, the mass and volume of the apparatus had to be kept more or less constant. Even though not all the experiments went as planned, the launch on 2 December proved that, at least in principle, the increasingly miniaturized technology works in space.

QUANTUS IV – MAIUS project

The MAIUS-2 mission is carried out as part of the QUANTUS IV – MAIUS project. This project is being run by the Centre of Applied Space Technology and Microgravity (ZARM) – based at the University of Bremen – in conjunction with Leibniz University Hannover, Humboldt-Universität and the Ferdinand-Braun-Institut (both in Berlin), as well as Johannes Gutenberg Universität in Mainz. Other members of this research alliance are the German Aerospace Center’s (DLR) Hannover-based Institute for Satellite Geodesy and Inertial Sensing, the DLR’s Braunschweig-based Institute for Software Technology and the DLR’s Mobile Rocket Base (MORABA), which also executed the launch campaign. The project is coordinated and supported by the German Space Agency at DLR, with funding from Germany’s Federal Ministry for Economic Affairs and Climate Action (BMWK).