Grissom IV is a planet located in or near the Koprulu Sector. It features constant torrential downpours, seemingly ignoring all common laws of meteorological science. The chaotic ferocity of these storms has resulted in the severe erosion of the planet's surface, creating strange shapes in the terrain and occasionally uncovering vast amounts of resources. The weather is so harsh only the most desperate of prospectors visit.
The planet was probably named after one of the first American astronauts, Gus Grissom, who was a member of Project Mercury and died during a training exercise for the Apollo One mission.