Colonization of the outer Solar System is subject to only 0.01 rem a day. When NASA carried out a study called "HOPE" (Revolutionary Concepts for Human Outer Planet Exploration) regarding the future exploration of the Solar System, the target chosen was Callisto. It might be possible to build a surface base that would produce fuel for further exploration of the Solar System. The Keck Observatory announced in 2006 that the binary Jupiter trojan 617 Patroclus, and possibly many other Jupiter trojans, are likely composed of water ice, with a layer of dust. This suggests that mining water and other volatiles in this region and transporting them
Solar Jetman or anti-clockwise direction. The pod is subject to inertia but not drag physics depending on the level of gravity of the set planet. The constant pull of gravity changes every level, which makes stable flight challenging and manoeuvring the pod more difficult as the levels progress. "Solar Jetman" has twelve planets and one hidden planet, each with its own gravity and system of enemy-infested caverns. The goal is to navigate these caverns with small jetpods launched from an immobile mothership, on each planet bringing back a piece of the Golden Warpship and enough fuel to journey to the next one.