Over the past decade, Army unmanned aircraft systems have become an integral part of the United States military. There are approximately 1,300 U.S. Army unmanned aircraft in direct support of our Warfighters serving in countries such as Iraq, Afghanistan and elsewhere. The Army's Unmanned Aircraft Systems Project Office (UAS PO) under the management of the Program Executive Office for Aviation located on Redstone Arsenal, has the mission of finding, developing, acquiring and distributing every Army unmanned aircraft in the Army's unmanned aircraft fleet. "The Army's reliance on unmanned aircraft as a means to enable and increase combat capability continues to grow," said COL Gregory Gonzalez, Project Manager of the UAS PO. A significant challenge which hinders the U.S. military to operate, to test, and to train UAS in the U.S. National Airspace System (NAS) is the inability of UAS, as they operate today, to comply with Federal Aviation Regulations which require an aircraft to have the ability to "see and avoid" other aircraft . Since UAS do not currently operate with the capability to see and avoid other aircraft, they must conduct their operational, test, and training missions in restricted airspace. This restricted airspace is not used by UAS alone, as other military systems must share these same resources to conduct their testing and training missions as well. COL Gonzalez also stated, "The operation of unmanned aircraft in theater continues unabated, but as conflicts in Iraq and Afghanistan come to some resolution and more troops return to the homeland, they must be prepared to meet any future contingency that will jeopardize the security of our great nation. Proper training is the key to soldier readiness and we don't currently have enough restricted airspace throughout the continental United States to allow our unmanned aircraft operators to remain proficient." In order to maintain UAS as one of the Army's most effective tools used in conflicts around the world, an alternate means of compliance to the "see and avoid" requirement must be developed. By expanding the airspace in which UAS may operate through achieving the ultimate goal of routine and unfettered access to the NAS, UAS operators will be able to conduct the training, testing and operational missions that allow them to maintain maximum levels of readiness necessary to respond to any situation. The UAS PO has been hand-selected by the Office of the Secretary of Defense to work with the FAA to develop a system allowing for unmanned aircraft flight within the national airspace. The UAS PO has assigned the Unmanned Systems Airspace Integration Concepts (USAIC PD) Product Office to serve as task force lead on behalf of the Department of Defense for Ground Based Sense and Avoid (GBSAA). USAIC's top priority is to develop and field a ground-based system that will allow unmanned aircraft to meet the regulatory guidance necessary to fly in the national airspace along with general aviation and commercial flights. In a manned aircraft, the pilot uses his eyes and brain to see and avoid other aircraft that he encounters during his flight. USAIC is designing an integrated system that uses ground-based sensors and associated components to "sense and avoid" these same aircraft. In essence, the GBSAA system will replace the pilot's eyes and his ability to make decisions to safely avoid other aircraft. COL Gonzalez goes on to say, "That's why our work on ground-based and airborne sense and avoid capabilities is crucial. Use of an approved sense and avoid system will allow unmanned aircraft safe, appropriate, and limited access to the national airspace to facilitate operator training within the boundaries of the U.S. The DoD's most successful effort to develop the ground-based sense and avoid system is being done right here at Redstone Arsenal by the Unmanned Aircraft Systems Project Office." Developing and validating a technological capability that allows a UAS to safely "sense and avoid" other aircraft will provide an alternate means of compliance to the "see and avoid" regulation. Significant effort and accomplishments in the development of an Army GBSAA system as a practical solution to gain initial access to the NAS are underway. USAIC has successfully developed a proof-of-concept GBSAA system which is now deployed at El Mirage, CA. This system is being used to test the Army's approach to incremental access to the National Airspace System (NAS). On 18 August 2010, the FAA granted the Army approval of the historic first flights of unmanned aircraft in the NAS without chase planes or ground observers using this GBSAA system. Currently, the FAA and the Army are negotiating the associated terms of an agreement between the FAA and DoD concerning sharing of data collected from this first proof of concept system. The ground-breaking first flights using this GBSAA system are expected to occur in March 2011 using the Army's Gray Eagle UAS. At this time, GBSAA efforts are focused on Gray Eagle operations at an airfield during takeoff and landing and on flying to restricted airspace through a pre-designated tunnel. Future development will expand on current efforts to allow more freedom for UAS to maneuver in the operational area. In parallel, requirements for sense and avoid functionality are being written for future SAA systems to include Airborne SAA (ABSAA). As these systems and technologies are being developed and successfully tested, the SAA capability continues to grow into what will one day be an integrated airborne/ground-based solution that allows unfettered access to the NAS for UAS. The Army UAS PO has identified the need for both air and ground-based SAA solutions. Along with GBSAA, the UAS PO has begun testing of SAA technologies that can be carried on an unmanned aircraft platform. The Small Sense and Avoid System (SSAASy) is an electro-optical sensing capability integrated onto the nose of a Shadow 200 Unmanned Aircraft. The system is designed to sense other aircraft and provide awareness to the ground operator. The initial demonstration from a recent test was successful and is a first step towards the development of an Army Airborne SAA system. As this capability continues to improve and GBSAA becomes more mature, the capabilities demonstrated by SSAASy can be integrated with ground-based sensors to provide more complete information to the UAS operator alerting him to other aircraft that he will need to avoid. This future integration of airborne and ground based sensors will allow for greater Sense and Avoid capability for unmanned flights in the NAS. In conclusion, the Army has gone above and beyond to successfully develop and carry out tests of aerial and ground-based sense and avoid capabilities on unmanned aircraft. In addition, the Army has gained FAA approval for flights in the NAS with the first SAA system. As unmanned aircraft return home from theater, the aircraft operators will need to remain at peak training readiness in order to support the next unforeseen challenges that they will inevitably face. To enable this readiness, the Army's USAIC PdO, UAS PO and Program Executive Office Aviation continues to clear the way for unmanned aircraft flight within the NAS.