NASA's Deep Space Network (DSN or Network) is a central component of the Agency's space communications and navigation capability, providing deep space missions with tracking, telemetry, and command services needed to control spacecraft and transmit data. Part of NASA's Space Communications and Navigation (SCaN) Program, DSN operates antennas and transmitters at communications complexes in three locations: Goldstone, California; Madrid, Spain; and Canberra, Australia. NASA has contracts with the Spanish and Australian governments to manage day-to-day operations at the foreign sites and with the Jet Propulsion Laboratory (JPL), a federally funded research and development center in Pasadena, California, for the Goldstone site. During fiscal year (FY) 2014, DSN supported more than 30 missions including the launch and orbit insertions of NASA's Mars Atmosphere and Volatile Evolution Mission and the Indian Space Agency's Mars Orbiter Mission. Much of DSN's hardware is more than 30 years old, costly to maintain, and requires modernization and expansion to ensure continued service for existing and planned missions. Accordingly, in 2009 DSN management proposed an upgrade project to build new antennas and transmitters between 2009 and 2025. DSN has significant information technology (IT) and physical infrastructure components that it must protect against compromise from cyber attack, espionage, and terrorism. To this end, the JPL, Madrid, and Canberra agreements require each contractor to follow specified Federal and NASA security policies. We conducted this audit to examine whether DSN is positioned to meet current and future communication commitments and appropriately managing Network IT and physical security risks. We also considered whether NASA is effectively administering the contracts relating to the foreign sites. Although DSN is meeting its current operational commitments, budget reductions have challenged the Network's ability to maintain these performance levels and threaten its future reliability. Specifically, in FY 2009 the Network implemented a plan to achieve $226.9 million in savings over 10 years and use most of that savings to build new antennas and transmitters. However, in FY 2013 the SCaN Program cut the Network's budget by $101.3 million, causing DSN to delay upgrades, close antennas, and cancel or re-plan tasks. In addition, SCaN officials are considering additional cuts for DSN in FY 2016 that could further delay maintenance and upgrade tasks. Finally, despite these reductions DSN has not revised life-cycle cost estimates for the upgrade project or performed a detailed funding profile beyond FY 2018, making it difficult to effectively plan and justify funding for the project and DSN's future commitments. If budget reductions continue, DSN faces an increased risk that it will be unable to meet future operational commitments or complete the upgrade project on schedule.