Acquisition, Tracking, Pointing, and Fire Control Program [ATP-FC]

ln its 1984 directed energy plan, SDI0 planned to develop an acquisition, tracking, pointing, and fire control (ATPAWs) ubsystem for directed energy weapons by fiscal year 1990 for $1,298 million. Through fiscal year 1993, SDIO allocated $1,634 million to this program, accomplishing some but not all of the program objectives. SDIO estimated that it will cost $180 million and take 3 years to resolve the majority of the remaining technical issues. For another $100 million, the ATP technology could be demonstrated in space.

All directed energy weapons need an ATP/FC system. In general terms, the system must quickly engage a large number of targets by placing a directed energy beam on the aim point of each target. These time and accuracy constraints dictate a rapid succession of handovers from one sensor to another. Each successive sensor in the system has a smaller field of view and greater accuracy.

The system locks on to the infrared signature of a missile (acquisition); calculates the flight path of themissile (tracking); calculates an aim point on the missile and directs the beam to the aim point (pointing); and assesses the results and selects the next target (fire control). Depending on the mission of the directed energy system, the ATP/FC system must perform these functions when ballistic missiles are in their boost, post-boost, and/or midcourse phases of flight.

The basic goal of the program was to resolve the technical issues sufficiently to support a space test of a directed energy weapon by 1990. The overall technology performance objectives in the 1984 plan were as follows.

• Reduce the effect on the accuracy of pointing and tracking devices of vibrations caused by operation of the spacecraft and laser to less than 4 inches on the target.
• Develop the capability to rapidly retarget the laser beam from one target to another in less than 2 seconds.
• Develop the capability to track targets at ranges of 2,600 to 3,100 miles at an accuracy of about 4 inches.
• Develop fire control computer software to handle more than 100 targets at a rate of more than one target per second. The fire control functions are missile plume to missile hardbody handover, tracking of multiple targets, target identification, aim point selection, and damage assessment.

The plan specified that $1,298 million would be required from fucal years 1986 through 1990 to develop the system components and to fly space experiments to resolve integration and space operation issues. Experiments would permit the space test of a directed energy weapon in 1990.

SDIO met the plan's objectives for pointing and tracking technology and rapid retargeting technology for directed energy weapons. It did not meet the objectives for developing long-range fine tracking and fire control software. While not meeting all objectives, SD10 believes it has met the basic program goal of resolving technical issues sufficiently to support a space test of directed energy technology. Through fiscal year 1993, SDIO spent about $1,684 million developing ATP/FC technologies. This amount is about $286 million more than SD10 estimated was needed to accomplish the objectives. A majority of the funding was spent on a series of space- and ground-based experiments. All major space tracking experiments were canceled before completion due to a lack of funding. However, two space pointing experiments were completed.

At a cost of about $262 million, SDIO reported that it completed the Relay Mirror Experiment and the Low Power Atmospheric Compensation Experiment, which were focused on resolving issues related to the ground-based laser program. Each was placed in a separate orbit by one Delta booster in 1990. The Relay Mirror Experiment successfully demonstrated high-pointing accuracy, laser beam stability, and long-duration beam relays. The Low Power Atmospheric Compensation Experiment successfully demonstrated low-power technology to compensate for laser beam distortions, which occur when beams go through the atmosphere from ground to space.

SDI0 had spent about $684 million from fiscal years 1985 through 1991 planning, designing, and fabricating hardware for four ATP/FC space experiments that were canceled before completion for the following reasons.

• Talon Gold was intended to demonstrate precision tracking and pointing in space for targeting satellites and boosters. After spending about $26 million on Talon Gold, SDIO canceled the experiment because the cost estimates for integration and launch had increased an additional $600 million.
• Pathfinder was started in September 1986 and was canceled in 1987 because it was too expensive. SD10 had spent about $40 million on this experiment, which was to address plume phenomenology using a sensor array on the space shuttle.
• The Starlab space experiment was intended to demonstrate precision tracking and would have used the space shuttle to accomplish the experiment. After spending about $603 million developing Starlab, SDIO canceled this experiment in part because the Challenger accident led to nearly a 3-year delay in the launch date, greatly increasing the overall cost. This coupled with changing priorities in the directed energy program led to changes in requirements and increased costs, which made the experiment too expensive to complete.
• Altair, which was canceled after SDIO had spent about $16 million in development costs, was intended to demonstrate the same types of technologies as Starlab and was planned to use some of the hardware developed for Starlab. An SDIO official estimated that it would have cost $330 million to complete Altair.

SDI0 replaced the Altair space experiment with a nonspace ATP/FC experiment called High Altitude Balloon Experiment, This experiment was intended to achieve most of the same objectives as Altair but at a much lower estimated cost of $76 million. Balloons were used to carry AW/FC devices to an altitude of about 30 kilometers where these devices will be used to acquire and track missiles in the boost phase. SDIO'S program manager for ATP/FC expected this experiment to yield from 80 to 90 percent of the data that would have been obtained from a space experiment.

SDIO designed and constructed a Rapid Retargeting / Precision Pointing [R2P2] simulator that emulated the dynamics of a large spacecraft (e.g., motion and vibration). Using this facility, SDI0 developed and tested techniques for ensuring the stability, accuracy, and precision of a simulated directed energy weapon's pointing device under rapid retargeting situations. This project demonstrated, within the limits of a ground laboratory, that ATP/FC techniques should work in space at the levels established in the original program plan. SDIO will have spent about $42 million on this project from fiscal years 1986 through 1993.

Two other projects also demonstrated ATP/FC techniques. The Space Active Vibration Isolation project developed and tested ATP/FC techniques for negating the effects of spacecraft and weapon vibrations on the pointing device. This project produced hardware and technology that have improved the pointing stability of directed energy devices to below the program goal of less than 100 nanoradians, or about 4 inches from a distance of 1,000 kilometers. This project was followed by the Space Integrated Controls Experiment, which improved the pointing stability even further. SDIO spent about $37 million on these two projects from fiscal years 1986 through 1993.

As of 1993 SDIO estimated that it would cost $180 million and take three more years to resolve the vast majority of the ATP/FC technical issues and perform integrated ATP experiments against real targets from the High Altitude Balloon Experiment platform. This would substantially complete the objectives of the 1984 plan. An additional $100 million would be needed to demonstrate operation in space, assuming that it would be done as part of another directed energy space experiment such as Star LITE, the experiment planned for the chemical laser. The major technical issues to be resolved from 1993 through 1996 included long-range fine tracking, fire control, integrated ATP/FC, and additional concept development.

For long-range fine tracking, the Solid State baser Radar Source program produced two laser illuminators. They still need to be tested in realistic target environments to determine their effectiveness in changing conditions and against a wide variety of targets. In addition, their capabilities must also be developed to support aim point selection and maintenance and damage assessment.

Fire control decision software had been demonstrated in computer simulations, but its practicality and robustness had yet to be tested in an integrated field operation. Each of the individual fire control decision algorithms needs to be tested with several sets of scene conditions with real data. Functional integration with sensors and autonomous operation must also be demonstrated. SDIO plans to test the operation of the software on the High Altitude Balloon Experiment platform against boosting targets at the White Sands Missile Test Range.