Prospect for tracking spacecrafts within 2 million Km of earth with phased array antennas

Recent advances in space technology for Earth observations, global communications, and positioning systems have created heavy traffic at a variety of orbits. These include smart sensors in low Earth orbits (LEO), Internet satellites in LEO and GEO orbits, Earth observing satellites in high Earth orbits (HEO), observatory class satellites at Lagrangian libration points, and those heading for deep space. In such an integrated operations environment, future ground tracking antenna networks, such as JPL/NASA's deep space network (DSN) may be required to provide highly agile beams, flexible scheduling, and the capability for simultaneous tracking of multiple spacecrafts at various orbits. In this paper the possibility of cost-effectively replacing the DSN's 26-m antennas with a network of phased array antennas capable of tracking various types of spacecrafts that are within 2 million km of Earth is examined.