The Expedition 52 crew insignia
Our planet is shown surrounded by an imaginary constellation shaped like a house, depicting the theme of the patch: “The Earth is our home.” It is our precious cradle, to be preserved for all future generations. The house of stars just touches the Moon, acknowledging the first steps we have already taken there, while Mars is not far away, just beyond the International Space Station, symbolized by the Roman numeral “LII,” signifying the expedition number.
The planets Saturn and Jupiter, seen orbiting farther away, symbolize humanity’s exploration of deeper space, which will begin soon. A small Sputnik is seen circling the Earth on the same orbit with the ISS, bridging the beginning of our cosmic quest till now: Expedition 52 will launch in 2017, sixty years after that first satellite.
Two groups of crew names signify the pair of Soyuz vehicles that will launch the astronauts of Expedition 52 to the Station.
http://www.collectspace.com/ubb/Forum18/HTML/001289.html
https://www.flickr.com/photos/nasa2explore/27455941791/
https://www.nasa.gov/mission_pages/station/expeditions/expedition52/index.html (PDF)