On Shell 5, go to the Ankaran Research Lab. Once inside the building, go northwest. You will reach a room with some tables and what appears to be a dismantled missile. Put your pointer over it and you will learn that there is an item that you can pick up. It is a "Sturdy Heart". However, if you leave the building and return, it will be there again. You can repeat this process to get an unlimited amount of Sturdy Hearts, which you can sell at any store for an unlimited amount of money.