30. November 2016

Plas­ma re­search on the ISS

Rev­o­lu­tion­ary plas­ma lab­o­ra­to­ry: Eko­Plas­ma
Image 1/6, Credit: DLR (CC-BY 3.0).

Revolutionary plasma laboratory: EkoPlasma

View of the two new plas­ma cham­bers of the EKo­Plas­ma project: The al­most spher­i­cal do­dec­a­he­dron cham­ber and the ZyFlex cham­ber with vi­o­let plas­ma light are vis­i­ble in the fore­ground. The new Plas­mal­a­bor is to be trans­ferred to the ISS in 2020.
Float­ing plas­ma crys­tal
Image 2/6, Credit: DLR (CC-BY 3.0).

Floating plasma crystal

A two-di­men­sion­al plas­ma crys­tal was cre­at­ed in the ZyFlex cham­ber, where it floats like a 'red oval cloud’ above the low­er elec­trode.
View of the Columbus laboratory of the ISS
View of the Colum­bus lab­o­ra­to­ry of the ISS
Image 3/6, Credit: ESA/NASA

View of the Columbus laboratory of the ISS

The Eu­ro­pean Colum­bus mod­ule of the ISS is a sci­ence lab­o­ra­to­ry. The im­age was sent by ESA as­tro­naut Alexan­der Gerst dur­ing his Blue Dot mis­sion in 2014. He com­ment­ed: "Our pow­er­ful Eu­ro­pean sci­ence lab­o­ra­to­ry in space.The re­search we con­duct here is not pos­si­ble on Earth!”
Plas­ma crys­tal ex­per­i­ment
Image 4/6, Credit: DLR (CC-BY 3.0).

Plasma crystal experiment

Orig­i­nal im­age of the par­ti­cle mo­tion in shear flow, caused by laser ex­ci­ta­tion.
Di­a­gram: Par­ti­cle cloud
Image 5/6, Credit: Donghua University/Du.

Diagram: Particle cloud

Re­con­struct­ed par­ti­cle mo­tion in the en­tire, three-di­men­sion­al par­ti­cle cloud with shear flow caused by laser ex­ci­ta­tion.
Cos­mo­naut Alexan­dr Samokutyaev
Image 6/6, Credit: DLR (CC-BY 3.0).

Cosmonaut Alexandr Samokutyaev

The Rus­sian cos­mo­naut Alexan­dr Samokutyaev re­port­ed on his work on board the ISS at the first PK-4 sym­po­sium at DLR in Oberp­faf­fen­hofen. Dur­ing his six month stay, he in­stalled the PK-4 lab­o­ra­to­ry in the Colum­bus mod­ule in Novem­ber 2014.

The plasma crystal experiments are among the most successful research projects on the International Space Station (ISS). The PKE-Nefedov plasma crystal laboratory was one of the first scientific research laboratories on the International Space Station (ISS). The PK-4 has been in operation in the Columbus module since 2014. More than 70 scientific publications confirm the knowledge gained from the experiments conducted over the last 15 years. The German Aerospace Center (Deutsches Zentrüm für Luft- und Raumfahrt; DLR) Com­plex Plas­mas re­search group is gaining fundamental insights into, in particular, solid state and fluid physics, as well as applications in space physics, plasma physics, plasma technology and fusion research. At the end of November, the international project and research partners met at a comprehensive symposium at the DLR site in Oberpfaffenhofen to present the results of PK-4 so far and to plan future activities.

The ISS provides ideal conditions for the investigation of plasma crystals and complex plasmas. A plasma is an electrically charged gas, a bit like lightning, which rarely occurs on Earth. In contrast, 99 percent of the visible matter in space is in the plasma state. When dust particles or other microparticles are also contained in the ionised gas, these are highly charged and a 'complex plasma' is formed: In microgravity, the particles can spread freely in space and form ordered three-dimensional crystal structures. The particles behave similarly to atoms in a solid or liquid – with the advantage that each microparticle in the plasma can be observed individually and as if in slow motion. This provides a whole new insight into physics.

Using PK-4 records, researchers can follow how a solid object melts, how waves spread in fluids and how currents change at the atomic level. Complex plasma is a new aggregate state of soft matter, in addition to colloids, polymers, foams, gels, granular media or even liquid crystals – a realisation that microgravity results have brought to light for the first time.

Knowledge and technology transfer

Through technology transfer, plasma research also opens up completely new fields of application. The starting point is to develop and build – using the know-how from human spaceflight – miniaturised, user-friendly and at the same time highly efficient laboratories taking into account special safety aspects for astronauts. A special transfer from space to Earth has already been achieved by scientists (at the time, the Max Planck Institute for Extraterrestrial Physics (MPE), now DLR) with the production of a plasma source for medical use. With this, the first clinical study on the use of plasma for chronic wounds was conducted – a milestone for plasma medicine. This young, fast-growing research field combines knowledge from the fields of plasma microscopy, microbiology and medicine.

"After the successes achieved with plasma medicine at MPE, the research group at DLR is now working on new follow-up projects. The so-called cold atmospheric plasmas from the medical field can also be used for space travel – especially for the sterilisation of surfaces and components, such as those of the Mars Rovers, which are searching for life. The use of plasma could also make hygiene on board the ISS much easier in future," says Hubertus Thomas, Head of the DLR Complex Plasmas Research Group. The projects for the use of cold atmospheric plasmas are funded by the Bavar­i­an Min­istry of Eco­nom­ic Af­fairs and Me­dia, En­er­gy and Tech­nol­o­gy.

International cooperation

The current research project and plasma laboratory PK-4 on the ISS is a European-Russian cooperation with research partners around the world. Approximately 60 participants attended the PK-4 symposium in Oberpfaffenhofen: The DLR Complex Plasmas research group welcomed the international team of scientists with participants from the European space agency ESA - Eu­ro­pean Space Agen­cy, the Russian space agency ROSCOSMOS, the US space agency NASA-NASA-Na­tion­al Sci­ence Foun­da­tion and the DLR Space Administration.

In a special guest speech, Cosmonaut Alexandr Samokutyaev also reported on his work on the ISS. In November 2014, together with colleague Elena Serova, the Russian installed the Plasma Crystal Laboratory and prepared for the first deployment: "Scientific experiments on the Space Station are very important and a core task for astronauts on board as they provide special insights for space travel and people on Earth. I am delighted to have been able to contribute with the PK-4 laboratory."

New experiments

During the symposium, the specialist community also discussed and expanded the long-term PK-4 programme. Next year, three new series of experiments are planned in the Plasma Crystal Laboratory, which is to be operated on the ISS at least until 2019. "We are delighted that the highly successful PKE-Nefedov and PK-3 Plus experiments with PK-4 have enabled us to continue plasma crystal research on the ISS in the years to come. The symposium has once again demonstrated how diverse this research area is, and that German scientists are conducting research in an international environment," explains Thomas Driebe from DLR's Space Administration at the event.

In parallel with PK-4, the plasma researchers are already developing two novel plasma chambers, which form the scientific and technical connection to PK-4 and the previous PKE-Nefedov and PK-3 Plus projects. The experimental EKo­Plas­ma set-up will be transferred to the ISS in 2020 and consists of a cylindrical 'Zyflex chamber' and a 12-surface 'Dodecahedron chamber'. These unique plasma chambers will enable the DLR research group to develop the research and application fields of complex plasmas further.

About the project

The PK-4 laboratory is a cooperation between the European Space Agency (ESA - Eu­ro­pean Space Agen­cy) and the Russian space agency ROSKOSMOS. The Russian part, scientifically involved through the Joint Institute for High Temperatures (JI­HT) at the Russian Academy of Sciences, is responsible for transporting the laboratory, transporting video data back to Earth and providing the crew time. The development of the PK-4 laboratory was also carried out in close contact with the JIHT. The experimental hardware is a proprietary development of the research group (at MPE) in cooperation with OHB Sys­tem AG (formerly Kayser-Threde GmbH), which was also responsible for the PK-4 infrastructure. Additional financing for the project in Germany came from the DLR Space Administration and the Max Planck Society.

  • Bernadette Jung
    Com­mu­ni­ca­tions Ober­paf­fen­hofen, Weil­heim, Augs­burg
    Ger­man Aerospace Cen­ter (DLR)

    Com­mu­ni­ca­tions and Me­dia Re­la­tions
    Telephone: +49 8153 28-2251
    Fax: +49 8153 28-1243
    Münchener Straße 20
    82234 Weßling
  • Hubertus Thomas
    Ger­man Aerospace Cen­ter (DLR)
    In­sti­tute of Ma­te­ri­al Physics in Space
    Head of Re­search Group Com­plex Plas­mas
    Linder Höhe
    51147 Cologne
  • Thomas Driebe
    Ger­man Aerospace Cen­ter (DLR)
    Ger­man Space Agen­cy at DLR
    Mi­cro­grav­i­ty Re­search and Life Sci­ences
    Königswinterer Straße 522-524
    53227 Bonn
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