Quantum-based communication is of prime interest to corporations and government agencies with high security requirements. In cases where classical schemes are not considered trustworthy, key distribution by courier is typically used. Unlike human courier networks, quantum cryptography has the ability to detect interception of the key, has greater reliability and operating costs, and is automatic and instantaneous. For long distance quantum communication to be practical, ground-to-space links are a necessity due to the current limitations of optical fiber and photon detectors in ground-to-ground links. Another application is all-optical quantum computing (i.e. linear optical quantum computing), where the lack of high-purity on-demand photon sources is the biggest obstacle. Satellite-based links established using on-demand single photon sources could provide a global quantum network. Additionally, a space-based implementation of the technology will answer important questions in fundamental physics by testing the properties of quantum entanglements over much greater distances than ever before, and due to earth's gravitational curvature may even provide an insight to the relationship between gravity and quantum physics.