References

TacSat / Joint Warfighting Space (JWS)

TacSat-2
(JWS D1, St 61SC0)
Near Real Time Tactical Military
S & T/R & D
RECSAT

TacSat-2

TacSat-2 is a small satellite for developing low-cost, customized and rapidly deployable space capabilities for theater warfighters. Work on TacSat-2 is being done at the Air Force Research Laboratory with help from the Naval Research Laboratory. This TACSAT demo was scheduled for 2007 as the first proof of concept for joint warfighters space (JWS). Plans are to provide the Joint Force Commander with an operational capability by 2010.

TacSat-2 begins a spiral development cycle. The second experiment in this initiative, TacSat-2, aims to build on TacSat-1, and continue to develop near-term paths for the tactical exploitation of space. These efforts have helped to create and institutionalize a joint TacSat experimentation program with the objective of testing key elements needed to realize a fully operationally system.

One objective of the TacSat-2 experiment is to develop an understanding of the requirements for and limitations of rapid deployment. This includes launch vehicle integration, launch, and on-orbit checkout of the satellite. A second objective is to understand the requirements and limitations for the rapid development of new spacecraft and payloads. From an operational standpoint, the program seeks to obtain high-resolution images of tactical significance using space research and satellite technology the vital mission operations center (VMOC) operational network to task the satellite and disseminate the resulting data. Another objective is to develop and test a concept of operations (CONOP) for the geolocation and cued imaging of a target during the same pass.

TacSat-2 also will experiment with autonomous flight software to perform on-orbit checkout of the spacecraft, and autonomous tasking of the various payloads carried by the spacecraft. The most important contribution of TacSat-2 is the use of a space-based common data link (CDL) tactical communications link. Flying a CDL transponder requires ground-breaking work in frequency allocations and communications security (COMSEC) approaches.

The TacSat-2 spacecraft carries a large number of experimental payloads. The payloads that primarily address operationally relevant tactical capabilities include the Target Indicator Experiment (TIE) supplied by naval research laboratory (NRL) and the imaging system supplied by Nova Biomimetics and SAIC. The TIE payload is an improved version of the primary payload carried by TacSat-1. The TIE payload performs real-time signal geolocation and SEI of radio frequency (RF) signals using space and air-based collection platforms. It is also capable of collecting the Automated Identification System (AIS) signal now required on large ships for port safety and homeland defense. The TIE payload is also reprogrammable on-orbit for acquiring new targets.

The TacSat-2 imaging system has panchromatic, red, green, and blue sensors with a ground sample distance (GSD) of approximately 1 meter. This imager uses a Fairchild Imaging CCD 583 TDI Line Scan array, sampling at approximately 9600 lines per second. The high ground scan speeds of TacSat-2 that resulted from its low Earth orbit (7.5 km/s satellite ground trace speed) are an ideal application for a time delay integration (TDI) approach. The TDI process is essentially noise-free, allows charge accumulation to take place over the number of TDI stages, and preserves the ground resolution capability of the very high rates that the TDI lines are “scanned” off the array.