[Satellite News 09-27-11] Orbital Sciences Corp. completed its 23rd consecutive successful Minotaur rocket mission, launching the U.S. Navy’s Tactical Satellite-4 (TacSat-4) into an elliptical orbit, the company confirmed Sept. 27. Sponsored by the Operationally Responsive Space (ORS) Office, the TacSat-4 program will demonstrate the use of standard interfaces to shorten development timelines while delivering tactical capabilities to the U.S. warfighter.

   The TacSat-4 launch was the fifth Minotaur 4 flight and the 23rd overall mission for the Minotaur product line since 2000. “The successful Minotaur 4 flight continues our well-established record of mission success for the Minotaur rocket family. Orbital is proud to support the U.S. Air Force with the newest member of the Minotaur launch vehicle family for the operationally responsive TacSat program,” Orbital’s Executive Vice President and General Manager of Launch Systems Ron Grabe said following the launch. “The Minotaur family has proven to be a valuable asset for the U.S. Department of Defense to meet its space launch needs.”

   TacSat-4, also known as the Tactical Microsatellite Innovative Naval Prototype, or INP, was developed under a new U.S. Navy policy to expand investment in spacecraft technology. TacSat-4, powered by twin solar arrays generating one kilowatt of power, features technology that allows flexible up- and down-channel assignments to increase the ability to operate in high latitudes and busy radio-frequency environments where users currently cannot access UHF satellite communications. The U.S. Naval Research Laboratory (NRL) Blossom Point Ground Station will provide command and control for TacSat-4. The U.S. Navy employed the Virtual Mission Operations Center (VMOC) mission planning system to allow rapid reallocation of the satellite to different theaters worldwide.

    “Ultimately, TacSat-4 will augment the existing fleet by giving the satcom support centers 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 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,” NRL said in a statement.

   NRL built the spacecraft bus in cooperation with Johns Hopkins University Applied Physics Laboratory (APL) and a consortium of aerospace companies including AeroAstro, ATK Space, Ball Aerospace and Technologies, Boeing, General Dynamics, Space Systems/Loral and Raytheon.

    “Communication is a critical warfighting requirement. TacSat-4 will support forward deployed forces at sea and Marines on the ground. We’ve developed a technology more rapidly and at lower cost that will supplement traditional satellites, giving multiple combatant commanders around the globe another outlet for data transmission and communications-on-the-move,” ORS Director Larry Schuette said in a statement.

   The TacSat program delivers a wide variety of unique capabilities to U.S. Armed Forces/ TacSat-3 was launched in May 2009 equipped with the Advanced Responsive Tactically Effective Military Imaging Spectrometer (Artemis) hyperspectral imaging experiment. After the experimental operation of the sensor was completed, the spacecraft was brought into service as was found to be able to locate roadside bombs and underground tunnels.

   TacSat-1 was originally intended to be the first TacSat spacecraft to demonstrate the provision of infrared and optical images directly to troops on the battlefield, but was never launched due to repeated delays. Most of TacSat-1’s mission, however, was completed by TacSat-2 and TacSat-1 was declared obsolete. The U.S. military also used the British TopSat spacecraft for a series of tests associated with the TacSat programme, which were identified as TacSat-0.