Traverse the ice field and Bring Moonstones to Mystic are missions in Going Commando taking place in the Tundor Wastes, Grelbin. When Angela Cross invited Ratchet and Clank to meet her on Grelbin, they decided to explore the ice field near where they landed. In doing so, they found the Mystic, who claimed to be capable of lifting a rock blocking the way inside the ice field if he was given nine moonstones found in Grelbin. Ratchet and Clank obliged.
This mission only involves combat in the later segment, as the first revolves around using the Glider in a particularly difficult path.
When you arrive in the mine shaft, use the Glider at the launch platform, being particularly careful to avoid the falling stalactites and pass through the narrow gaps by staying close to the edges. Eventually, you will reach a dead-end with an opening in the floor down to a smaller cave with lava beneath it; sharply turn down and head through to the end. All in all it might take several tries, but it is recommended to stay aware of the path and the various twists and turns it makes, preparing oneself to avoid being surprised and making rash movement is key to making it through.
Once landed, use the Infiltrator to unlock a door. The rest of the mission is a mostly linear path, in which you must defeat the 3.0 Receiver Bots. These enemies have rapid-fire blasters on their arms that can deal significant damage and overwhelm you if you are not cautious. They are best dealt with using the Hoverbomb Gun, Plasma Coil, or Bouncer, due to their area of effect, while the Shield Charger is also particularly helpful for absorbing their damage.
At the end, you will reach an elevator up to a small area with an armor vendor. The Carbonox armor is available now, but at 1,000,000 bolts, it is not affordable (and not necessary before a challenge mode playthrough anyway). Instead, simply use the Infiltrator at the end of the room to open a door back to your ship. Doing so will also open bridges to the upper portion of the ice field, allowing you to continue "Trade moonstones for Hypnomatic Part".