During the return to Earth, Mattingly performed an 83-minute EVA to retrieve film cassettes from the service module's scientific instrument module (SIM) bay, with assistance from Duke who remained at the command module's hatch. At approximately 173,000 nautical miles (199,000 mi; 320,000 km) from Earth, it was the second "deep space" EVA in history, performed at great distance from any planetary body. As of , it remains one of only three such EVAs, all performed during Apollo's J-missions under similar circumstances. Additionally, Mattingly set up a biological experiment, the Microbial Ecology Evaluation Device (MEED), an experiment unique to Apollo 16. The crew carried out various housekeeping and maintenance tasks aboard the spacecraft and ate a meal before concluding the day.