As an operating division of Caltech situated in Pasadena, California, JPL is a federally funded research and development center. The Laboratory is primarily known as the leader of America's unmanned exploration of the solar system, although it also conducts work for other federal agencies in aviation, biomedicine, defense, environmental sciences, and industrial processes.

Systems capable of handling two-way communications with spacecraft over the vast distances in lunar and planetary missions are a vital element in all space flight projects. These communications systems have been pioneered in many critical areas by JPL. For nearly two decades MODCOMP real-time computer systems have performed crucial functions in the operation of JPL's communications systems.

At both the Deep Space Network (DSN) and the Mission Control Computer Center (MCCC) over two hundred fifty MODCOMP systems monitor and control vital performance standards and measurements. The MODCOMP II, IV, CLASSIC, and REAL/STAR series systems along with the MAX (Modular Application Executive) and REAL/IX real-time operating system have demonstrated years of reliability, high-performance, and compatibility in an environment which performs state-of-the-art scientific and engineering marvels. In addition, MODCOMP's real-time systems are also used for hardware and software development and generation of applications programs.

At the DSN, MODCOMP processors are utilized as monitoring and control systems. Some systems are used as front-ends for error correction and switching, while others are used to generate real-time displays for the DSN and MCCC controllers, to monitor the performance of DSN systems, scientific data monitors, and control processing monitors.

Operated by JPL for NASA, the DSN today communicates with and tracks automated spacecraft circumnavigating the entire solar system. Providing tracking information for all of NASA's unmanned missions in deep space, the DSN also receives engineering and science telemetry data and range and range- rate information which is forwarded to appropriate mission control centers, one of which is located at JPL. Telemetry data is analyzed and evaluated by engineers and scientists and is used to generate commands which are transmitted back to the spacecraft. Range and rangerate data provide project navigation teams the information necessary to locate spacecraft and provide navigation control.

MODCOMP systems' performance has been an essential ingredient to the success of the Voyager missions. Real-time monitoring and control is absolutely imperative during a spacecraft encounter with Jupiter or Saturn. Equally important, the processing of data transmitted from Saturn or Jupiter to Earth and ultimately to JPL via satellites and the receiving stations of the DSN enhance the mission's objectives. Spacecraft performance is tracked, monitored, and controlled in real-time always communicating the status of spacecraft subsystems, experiments being conducted, data retrieved, power and trajectory, and telemetry for both scientific and engineering measurements.

The exploration of the universe is limited only by man's will to challenge the unknown and the outer limits of space. Together, JPL and MODCOMP have taken giant steps toward extending the boundaries of scientific and engineering knowledge, and at the same time have traversed new, distant reaches of our universe.