Gateway Galaxy

The Gateway Galaxy is one of the many Galaxies from Super Mario Galaxy for the Wii. Princess Rosalina calls this galaxy the "Gateway to the Starry Sky". It serves as the opening level for the game and is the location of the Comet Observatory. This is the first Galaxy in the game, and after Mario clears the first level in the Galaxy, he won't be able to return until he unlocks the Garden, later on in the game.

Grand Star Rescue
When Mario awakens on this planet, a Space Bunny will challenge him to a game of hide-and-seek. Follow the bunny until he reaches his two friends, who will run and hide. One is found near a crate, another in a crater, and the last in a Warp Pipe. Catch them all, and a new structure on the planet will appear. Mario will meet with Princess Rosalina and gain the Star Spin ability. Spin the nearby Launch Star to reach the next planet, which has five Star Chips scattered about. Grab the Star Chips to make a Launch Star and blast Mario to the next planet. Here, a Luma in a cage tells Mario that one of the Goombas on the planet has the key. Kill the Goombas on the planet until one gives up a key. Collect the key to free the Luma. The Luma then transforms into a Sling Star, which slings Mario to the next planet. On this planet, Mario must kill the Giant Goomba near the top of the planet to free the other Luma and enter the Warp Pipe. The inside of the planet is filled with yellow switches and moving electrical walls. Mario needs to stand on all the yellow switches to turn them blue, which will reveal the Grand Star.

Gateway's Purple Coins
This Power Star is only accessible after the Garden has been opened, when a Purple Comet appears over the Gateway Galaxy. When Mario enters the galaxy, Rosalina will meet him and a Red Luma will challenge him to gain one hundred Purple Coins. Seventy coins are on the planet and thirty are in the air. Mario must use the new Red Star to gain the thirty in the air.