When Cecil and his allies Rosa, Rydia, Kain, Edge come with him on the Whale spaceship and fly to the moon, they can pilot it until they land it. But when they exit outside, they walk around without their spacesuits. This would cause them to die including Fusoya and Golbez, because first of all, there's no life on the moon including trees or water. Second, they would freeze to death or burn to death by the sun due to extreme heat and cold temperatures caused by the sun or no sun. Also gravity on the moon is different than Earth and they would bounce lightly and float on the moon. If they were provided spacesuits with oxygen tanks, then they would be able to survive on the moons surface but would have limited time to explore and fight before returning on the spaceship. However, their spacesuits would make them more vulnerable to monster attacks and it would be slightly harder to use weapons due to the moons lighter gravity.