PK-4: exploring plasmas in microgravity – understanding atomic processes

In the PK-4 facility cold plasmas containing particles are analysed
In the plasma crystals experiment PK-4, cold plasmas containing particles are analysed. This experiment allows for processes that actually take place at the atomic level to become visible to the human eye. PK-4 serves as a versatile tool, enabling scientists to illuminate elementary physical processes and with that to facilitate new technological developments.


Plasma crystal experiments are a flagship European-Russian project as they are among the most successful research efforts having taken place on the International Space Station ISS. The PKE Nefedov plasma crystal facility was one of the first scientific research laboratories on the ISS. More than 70 scientific publications have documented the findings from the experiments carried out over the last 15 years. Its successor, PK-4, has been operating in the Columbus module since 2014. Thanks to these ISS facilities, researchers are gaining fundamental insights – particularly in solid-state and fluid physics. In addition, applications in space physics, plasma physics and technology as well as technological fluids benefit from this work.

Plasma is an ionised and thus electrically conductive gas that is used in semiconductor and chip technology as well as recently in applications in the field of medicine, to kill multidrug-resistant bacteria in wound treatment and disinfection. If dust particles or other microparticles are also contained in the plasma, they become highly charged, resulting in a 'complex plasma'. Under microgravity conditions, the particles can spread out freely in space and form ordered, three-dimensional crystal structures. The particles behave in a way similar to atoms in a solid or a liquid, with the advantage that in the plasma each microparticle can be observed individually, as though in slow motion.

Researchers can use this to track at an 'atomic' level how a solid melts, a glass forms or flows in liquids change. The results will broaden the understanding of complex plasmas and will play a role in condensed matter physics. Business applications are expected in the fields of semiconductor production (microchips) and electronically controlled liquids, which are used in modern motor drives, valves and shock absorber systems.


Elke Heinemann

Digital Communications
German Aerospace Center (DLR)
Corporate Communications
Linder Höhe, 51147 Cologne
Tel: +49 2203 601-1852

Volker Schmid

ISS Specialist Group Leader, Head of the Cosmic Kiss Mission
German Aerospace Center (DLR)
German Space Agency at DLR
Science and Exploration
Königswinterer Straße 522-524, 53227 Bonn

Martin Fleischmann

Communications & Media Relations, Print Editor
German Aerospace Center (DLR)
German Space Agency at DLR
Königswinterer Straße 522-524, 53227 Bonn
Tel: +49 228 447-120