Sci-Tech

Missile-tracking satellites launched on demo flight

NASA launches a pair of experimental missile-tracking satellites for the U.S. Missile Defense Agency, part of a $1.5 billion demonstration that could lead to an operational fleet.

A United Launch Alliance Delta 2 rocket roared to life and thundered away from the Cape Canaveral Air Force Station Friday, successfully boosting a pair of experimental missile-tracking satellites into orbit for the U.S. Missile Defense Agency.

A United Launch Alliance Delta 2 rocket blasts off from the Cape Canaveral Air Force Station Friday carrying two Missile Defense Agency tracking satellites, part of a $1.5 billion technology demonstration mission. NASA TV

With its roots in the old "Star Wars" program, the goal of the $1.5 billion Space Tracking and Surveillance System mission is to demonstrate the ability to detect and track enemy missiles from launch, through the so-called mid-course phase of flight to atmospheric entry, providing more accurate targeting data for interceptors.

"The purpose of these satellites is to enable acquisition and precision tracking from space, tracking of a sufficient quality to enable an interceptor to close the fire control loop, that is, to be able to determine a fire control solution based on information from space," said Rear Adm. Joseph Horn, deputy director of the Missile Defense Agency.

The results of the demonstration mission, he added, "will guide our decisions on the development of an affordable, continuously available, operational, precision-track space sensor constellation."

Running two days late because of bad weather and a small ground system fuel leak, the Delta 2 blasted off at 8:20 a.m. EDT from launch complex 17B at the Cape Canaveral Air Force Station, 20 minutes late because of morning rain showers. NASA managed the launching for the Missile Defense Agency.

Built by Northrup Grumman Aerospace Systems, the two solar-powered satellites boosted into space by the Delta 2 trace their heritage to President Ronald Reagan's Strategic Defense Initiative, which envisioned a constellation of missile-tracking satellites in low-Earth orbit.

The original tracking satellite concept evolved into the "Brilliant Eyes" program, which later was transferred to the Air Force and ultimately became part of the Space-Based Infrared System, or SBIRS.

SBIRS had two components: satellites in geosynchronous orbit intended to replace aging Defense Support Program - DSP - early-warning spacecraft, and a constellation of tracking satellites in low-Earth orbit. Brilliant Eyes was redesigned to become the lower-altitude component of the system.

Work on two demonstration satellites was started under the Brilliant Eyes program and later put on hold in favor of a different approach. In 2002, mission managers decided to press ahead with the demonstration satellites under management of the U.S. Missile Defense Agency.

A schematic showing how new missile-tracking satellites, working with gound- and sea-based sensors, can track an enemy missile through all phases of flight, providing precision targeting data for interceptors. Missile Defense Agency

The 2,200-pound satellites are equipped with horizon-to-horizon missile detection sensors and a narrow-angle tracking telescope that can follow an enemy missile in flight, even during the mid-course phase of flight when it is most difficult to detect. The sensors were built by Raytheon.

By combining tracking data from two spacecraft, computers can assemble a three-dimensional view of a missile's trajectory and quickly provide targeting information to future interceptors.

At least that's the idea. The new spacecraft will spend two to four years carrying out a series of tests to demonstrate the effectiveness of the technology, working in concert with two earlier experimental satellites. Whether the STSS demonstration program will spur funding and development of an operational constellation remains to be seen.

"The greatest hedge against missile defense threats of all ranges remains a highly available, early missile-tracking capability from space," Horn said. "With the successful launch of these two demonstrator satellites, we enter into an orbit checkout period after which we plan to use both targets of opportunity and dedicated targets to demonstrate STSS capabilities."

The requirements for an operational constellation are not yet defined, Horn said, but "what we expect to learn from these two demonstrators is exactly that, the (number) of satellites necessary to support a constellation and provide that continuous precision tracking information."