The Naval Research Laboratory's Tactical Satellite IV (TacSat-4) has been encapsulated inside the fairing (nose cone) of an Orbital Sciences Corporation Minotaur-IV+ launch vehicle in preparation for a Sept. 27 launch from the Alaska Aerospace Corporation's Kodiak Launch Complex.

The Office of Naval Research (ONR) sponsored the development of the payload and the first year of operations. The Operationally Responsive Space (ORS) Office funded the launch that is managed by the Space Development and Test Directorate (SD), a directorate of the Air Force Space and Missile Systems Center (SMC).

TacSat-4 is a Navy-led joint mission which provides 10 Ultra High Frequency (UHF) channels and allows troops using existing radios to communicate on-the-move (COTM) from obscured regions without the need for dangerous antenna positioning and pointing.

To augment current geosynchronous satellite communication, the TacSat-4 spacecraft will be deployed into a unique, highly elliptical orbit with an apogee in the high latitudes of 12,050 kilometers.

"Communication is a critical warfighting requirement," said Dr. Larry Schuette, ONR's director of innovation. "Developed, more rapidly and at lower cost, TacSat-4 supplements traditional communications satellites and provides much needed support to forward deployed forces at sea and Marines on the ground."

TacSat-4 provides flexible up and down channel assignments, which increase the ability to operate in busy radio-frequency environments and will cover the high latitudes and mountainous areas where users currently cannot access UHF satellite communications (SATCOMs).

The NRL Blossom Point Ground Station provides the command and control for TacSat-4. The Virtual Mission Operations Center (VMOC) mission planning system allows dynamic reallocation to different theaters worldwide that enables rapid SATCOM augmentation when unexpected operations or natural events occur.

TacSat-4 is an experimental spacecraft that will test advances in several technologies and SATCOM techniques. Ultimately, TacSat-4 will augment the existing fleet by giving the SATCOM Support Centers (SSC) an additional space asset to provide communications to otherwise under-served users and areas that either do not have high enough priority or do not have satellite visibility.

The project also helps define future options for launching one or more smaller, highly elliptical orbit (HEO) satellites allowing the military to achieve the benefits of a combined HEO and geosynchronous orbit constellation.

The spacecraft bus was built by NRL and Johns Hopkins University Applied Physics Laboratory (APL) to mature ORS bus standards. It was developed by an Integrated (government and industry) System Engineering Team, the "ISET Team," with active representation from AeroAstro, Air Force Research Laboratory, Johns Hopkins Laboratory APL, ATK Space, Ball Aerospace and Technologies, Boeing, Design Net Engineering, General Dynamics AIS, Microcosm, Microsat Systems Inc., Massachusetts Institute of Technology Lincoln Laboratory, Orbital Sciences, NRL, SMC, Space System Loral, and Raytheon. The Office of the Director of Defense Research and Engineering (DDR and E) funded the standardized spacecraft bus.

TacSat-4 is managed by the Naval Research Laboratory Naval Center for Space Technology and will be the 100th NRL built satellite launched into a celestial orbit.