iss056e098196 (July 23, 2018) --- Expedition 56 Flight Engineer Sergey Prokopyev, from Roscosmos, works with Plasma Kristall-4 (PK-4) science hardware inside the International Space Station's Columbus laboratory module from ESA (European Space Agency). The space physics study is investigating complex plasmas consisting of low temperature gaseous mixtures composed of ionized gas, neutral gas, and micron-sized particles. The results could benefit future spacecraft design and impact industries on Earth.