Computer model of TacSat-4
Mission typeTechnology
COSPAR ID2011-052A
SATCAT no.37818
Spacecraft properties
ManufacturerNRL (bus & payload)
APL (bus)
Launch mass460 kilograms (1,010 lb)
Start of mission
Launch dateSeptember 27, 2011 15:49 UTC (2011-09-27UTC15:49)
RocketMinotaur IV
Launch siteKodiak Pad 1
Orbital parameters
Reference systemGeocentric

TacSat-4 is the fourth in a series of U.S. military experimental reconnaissance and communication satellites. The Naval Research Laboratory (NRL) is the program manager. The Office of Naval Research (ONR) sponsored the development of the payload and funded the first year of operations. The Office of the Director of Defense Research and Engineering (DDR&E) funded the standardized spacecraft bus and the Operationally Responsive Space Office (ORS) funded the launch that will be performed by the Air Force's Space and Missile Systems Center (SMC).

The spacecraft was completed by the end of 2009, and was launched on September 27, 2011, on a Minotaur IV rocket into a highly elliptical orbit.[1][2][3][4]


TacSat-4 is equipped with a 3.8 m (12 ft) antenna operating 10 Ultra High Frequency (UHF) channels that can be used for any combination of communications, data ex-filtration or Blue Force Tracking (BFT). TacSat-4 will fly the highly elliptical, 4-hour, orbit (12,050 kilometers at peak) providing typical payload communication periods of two hours per orbit. TacSat-4's orbit also allows it to cover the high latitudes.

Part of its capability is rapid (within 24 hours) reallocation to different theaters worldwide, in support of unexpected operations. Command and control of TacSat-4 will be performed at the NRL Satellite Operations Center at Blossom Point, Maryland. Payload tasking will be performed via the SIPRNet based Virtual Mission Operations Center (VMOC).


All TacSat satellites are designed to demonstrate the ability to provide real-time data collected from space to combatant commanders in the field.[5]

The spacecraft bus was built by NRL and Johns Hopkins University Applied Physics Laboratory (APL) to mature ORS bus standards 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 & Technologies, Boeing, Design Net Engineering, General Dynamics AIS, Microcosm, Sierra Nevada Corp., Massachusetts Institute of Technology, Lincoln Laboratory, Orbital Sciences, NRL, SMC, Space Systems/Loral, and Raytheon. Li ion battery power provided by Quallion.


TacSat-4 with deployed UHF antenna
TacSat-4 at Naval Research Lab
Bus and COMMx payload
System overview


  1. ^ "Next launch: May 5". Kodiak Daily Mirror. March 1, 2011. Retrieved March 9, 2011.
  2. ^ "TacSat-4 spacecraft complete and awaiting launch". Naval Research Laboratory. December 1, 2009. Retrieved June 13, 2010.
  3. ^ "Worldwide launch schedule". Spaceflight Now. June 15, 2010. Retrieved June 16, 2010.
  4. ^ Brinton, Turner (August 30, 2010). "Rapidly Delivered Systems". SPACE NEWS. Retrieved October 25, 2010.
  5. ^ Ferster, Warren (November 7, 2005). "U.S. Air Force Payload for TacSat 4". Space News. Archived from the original on May 15, 2008. Retrieved July 28, 2008.

External links

  • TacSat-4 (Tactical Satellite-4), eoPortal, on the eo "Sharing Earth Observation Resources" website.