Williams and Skripochka wore face masks as they entered, which is standard procedure for initial inspections of cargo ships visiting the station. The duo collected an air sample, exited, and then re-entered to start gathering sensor data that was captured during the module's expansion on May 26 and 28.

Williams told ground controllers it was cold inside, and the temperature at the aft bulkhead read 44 degrees Farenheit, which was in line with pre-flight simulations.

The crew is finished working inside BEAM for the day. They have opportunities to reenter on Tuesday and Wednesday to deploy more sensors.

BEAM was expanded after a seven-hour, marathon work session back on May 28. It will remain aboard the station for two years. Astronauts will enter the module from time to time to collect data samples, but for the majority of time the hatch will remain closed.