A contract is a funding mechanism that is used to acquire items, products, property or services for the federal government's direct benefit or use. NASA's Science Mission Directorate uses contracts to acquire data and scientific results from flight investigations (typically resulting from selection under an Announcement of Opportunity) as well as flight hardware, mission operation services, science centers, etc. Contracts may be awarded to universities and other private institutions, but not to federal installations (like NASA centers). The Jet Propulsion Lab is operated by Caltech under a contract with NASA. Contracts are issued by one of NASA's procurement offices.