Irbid Corp. has spent US$3.5 billion over the past decade developing a satellite- based telecommunication system. It is currently trying to decide whether to spend an additional US$350 million on the project. The firm expects that this outlay will finish the project and will generate cash flow of US$15 million per year over the next 5 years. A competitor has offered US$450 million for the satellites already in orbit. Classify the firm's outlays as sunk costs or opportunity costs, and specify the relevant cash flows.