This secret planet is opened when Lupus finishes off Goldwood: Rim

It's sort of interesting, it cycles between light and dark because of the asteroids. All five teddy bears are right in the landing area - teddy bear gathering is not the main part of this planet.

In one of the houses is Yoda - he explains how you have to feed gems into a vacuum to give it power to save the planet. The other houses have coins and the robot.

The next room has the vacuum machine. Go underneath where the bear is, and wait for him to throw gems down to you. Shoot them over to the vacuum, and watch them get sucked in. Once you get enough gems into the machine, it will power up the guns and take care of saving the planet!

Jet Force Gemini Walkthrough