You will obtain a signal from a spaceship ready to land to help you, giving you coordinates of the "Mountain" island, wich is location of the Precursor gun. You will need to retrieve Purple Tablet in order to access the facility. Be sure to scan, and take every piece of equipment in your run, as well as lithium, and to explore the island. You dont really need to take food, or water with you, bulb trees located in the island, can provide while you explore. Be sure to activate the portal located in the island. Be sure to mark the location with a beacon, so you can come back later if needed. This achievement is actually obtainable in experimental