After listening to the transmission the students must put forward their suggestion and justify it. The groups must then reach a consensus - which planet should we go to. Further decisions must be made as to what tests are needed to determine the exact location of the missing space probe. Since each test costs money, there is an incentive to watch your spending to be competitive. The students knew quite a lot of facts about the solar system and this was not always helpful.
Students often burst with enthusiasm to jump the process and suggest a destination.
However, I always insisted that each person contributed before a consensus was reached. The accompanying worksheets require them to list their solutions and justifications - both for the individual and the group. This proved to be an excellent reinforcement for collaborative learning. It didn't provide the challenge I expected to their thinking skills since they often preferred to guess rather than think through the options eg. The package comes with all the necessary worksheets and information ready for use.