Underground day 2. <br /> <br />The cavenauts explore more of the Sa Grutta caves and set up a communication line. <br /> <br />An international crew of six astronauts are training for a caving adventure designed to prepare them for spaceflight. There are many similarities to spaceflight such as a lack of day--night cycle, sensory deprivation, minimal hygiene and the necessity to work as a team and solve problems together. <br /> <br />After a week of training they entered the caves to spend six days living and working underground.