In theory, the second PPH should be easy to access - Bob said it was right next to our ship on the overlook.
Unlike normal walkthroughs, in Nice Game Hints you can select just the puzzle you want hints for. Here are listed the puzzles for "The Second PPH" in Dexter Stardust: Adventures in Outer Space. The guide you choose only contains information about that puzzle, reducing possible spoilers for other puzzles.