APL is proud to conceptualize and implement highly classified and critically important spaceflight missions to enable our nation’s security. Generally, we design, build, and operate prototypes that accelerate space technology and space capabilities for the national security community. The following timeline illustrates some of these critical spaceflight milestones.
The world’s first satellite-based navigation system, Transit 1B was born days after the launch of Sputnik. Two APL scientists determined Sputnik’s orbit by analyzing the Doppler shift of its radio signals. If the satellite’s position was known and predictable, then Doppler shift could be used to locate a receiver on Earth. Development of the Transit constellation began at APL in 1958. The first prototype satellite was launched in September 1959. The Transit system, the precursor to today’s GPS, entered naval service in 1984.
The high latitude ionospheric research (HILAT) satellite was built to provide measurements of both ionospheric parameters and their effects on radio frequency wave propagation.
The GEOdetic SATellite (GEOSAT) was designed to measure sea surface height and carried an altimeter with a relative precision of about 5 cm.
The Polar Beacon Experiment and Auroral Research (PolarBEAR) spacecraft studied communications interference caused by solar flares and increased auroral activity. The core vehicle was a Transit navigational satellite that was retrieved from the Smithsonian’s National Air & Space Museum, where it had been on display for eight years.
Delta 183 was the third in the Delta series of experiments conducted by SOlO. It performed high-latitude observations of environmental backgrounds and made observations of auroral phenomena. The data collected was used in the design and engineering of a broad range of systems for strategic defense.
The Midcourse Space Experiment (MSX) was primarily a data collection experiment, concentrating on the phenomenology of target detection and tracking.
The Special Sensor Ultraviolet Spectrographic Imagers (SSUSI) sensed the physical and chemical processes in Earth’s upper atmosphere.
The Tactical Satellite 4 (TacSat-4) augmented capabilities to advance the state of Operationally Responsive Space (ORS) capabilities.
The Multimission Bus Demonstration (MBD Vector) presented a breakthrough capability for the military and intelligence communities, demonstrating that small satellites can get into orbit inexpensively and be tough enough for critical applications in these domains.
The Space-Based Kill Assessment (SKA) sensors improved hit and kill assessment of whether a threat missile has been eliminated by a missile defense interceptor.
The CubeSat Assessment and Test (CAT) established communications with two miniaturized satellites, or CubeSats, as part of an APL-led flight demonstration known as CAT. Each spacecraft carried an industry-provided radio frequency payload and had two identical 3U (nanosatellite) configuration CubeSats with two deployed solar panels.
The operational Deep Space Advanced Radar Capability (DARC) detects, tracks, and maintains custody of satellites.
