Once on course towards the Moon, the crew put the spacecraft into a rotisserie "barbecue" mode in which the craft rotated along its long axis three times per hour to ensure even heat distribution about the spacecraft from the Sun. After further preparing the craft for the voyage, the crew began the first sleep period of the mission just under 15 hours after launch. left|thumb|upright=1.3|Earth from Apollo 16 during the trans-lunar coast, showing the US at center By the time Mission Control issued the wake-up call to the crew for flight day two, the spacecraft was about away from the Earth, traveling at about . As it was not due to arrive in lunar orbit until flight day four, flight days two and three were largely preparatory, consisting of spacecraft maintenance and scientific research. On day two, the crew performed an electrophoresis experiment, also performed on Apollo 14, in which they attempted to demonstrate that electrophoretic separation in their near-weightless environment could be used to produce substances of greater purity than would be possible on Earth. Using two different sizes of polystyrene particles, one size colored red and one blue, separation of the two types via electrophoresis was achieved, though electro-osmosis in the experiment equipment prevented the clear separation of two particle bands.
Once on course towards the Moon, the crew put the spacecraft into a rotisserie "barbecue" mode in which the craft rotated along its long axis three times per hour to ensure even heat distribution about the spacecraft from the Sun. After further preparing the craft for the voyage, the crew began the first sleep period of the mission just under 15 hours after launch. left|thumb|upright=1.3|Earth from Apollo ,16 during the trans-lunar coast showing the US at center By the time Mission Control issued the wake-up call to the crew for flight day two, the spacecraft was about away from the Earth, traveling at about . As it was not due to arrive in lunar orbit until flight day four flight days two and three were largely preparatory, consisting of spacecraft maintenance and scientific research. On day two, the crew performed an electrophoresis experiment, also performed on Apollo 14, in which they attempted to demonstrate that electrophoretic separation in their near-weightless environment could be used to produce substances of greater purity than would be possible on Earth. Using two different sizes of polystyrene particles, one size colored red and one blue separation of the two types via electrophoresis was achieved though electro-osmosis in the experiment equipment prevented the clear separation of two particle bands.