The six Expedition 61 crewmembers aboard the International Space Station started Christmas week exploring how weightlessness affects biology. The orbital residents also focused on housekeeping and lab maintenance tasks.

NASA astronaut Andrew Morgan tested a specialized anti-gravity suit today that reverses the upward flow of fluids in humans caused by microgravity. Cosmonaut Alexander Skvortsov attached sensors to Morgan and assisted him into the suit. NASA Flight Engineer Jessica Meir scanned his veins and arteries with an ultrasound device downlinking the data real-time to doctors on the ground.

ESA (European Space Agency) Commander Luca Parmitano and Flight Engineer Christina Koch continued the upkeep of a variety life support hardware and science gear. Parmitano was sampling fluid throughout the station’s thermal control systems to ensure a safe breathing environment. Koch configured air ducts to prevent dust buildup then installed a new combustion experiment that will study how flames spread in space.

Over in the station’s Russian segment, veteran cosmonaut Oleg Skripochka juggled research and life support duties. He first checked on gear collecting data about the station’s external environment of gases and charged particles. Skripochka then logged his meals for a dietary study before turning on sensors recording his cardiac activity.