November 22, 2011
TacSat-4 Mission Tests New Spacecraft "Bus" Standards
An experimental satellite that will improve mobile communications for deployed troops is the first launch in a program led by APL and the Naval Research Laboratory (NRL), in partnership with the Operationally Responsive Space Office, to design standards for a spacecraft "bus" that can be used for various national security space operations.
Tactical Satellite-4 (TacSat-4), which launched September 27 aboard a Minotaur IV rocket from Kodiak Launch Complex, Alaska, expands satellite communications for soldiers using hand-held radios and delivers improved communications to the battlefield and problematic mountain regions. A small, low-cost spacecraft, TacSat-4 will allow troops to use standard military radios without stopping to point antennas toward a satellite.
The spacecraft is part of a Defense Department initiative to craft standards for a class of satellite that shares a common structure and onboard support system—and that can be adapted for a range of military operations. APL led an Integrated System Engineering Team of government and industry representatives that developed the standards; APL and NRL then built the TacSat-4 spacecraft to those specifications.
Technologies in the TacSat-4 prototype include a 12-foot ultra-high-frequency deployable antenna, advanced thermal control using several heat pipe technologies, and compact 10-channel transponder electronics. The solar-powered, 1,000-pound spacecraft, from a highly elliptical orbit around Earth, will test technologies and satellite communications techniques, and will give military satellite communication support centers better links to underserved satellite users and areas.
"TacSat-4 models what integrated teams like ours can do for the warfighter," says Patrick Stadter, the Operationally Responsive Space Bus Standards program manager, from the Space Department. "We’ve developed standards for a class of small, tactically focused space systems, and shown we can build and operate a spacecraft to those standards for a very important program. With the TacSat-4 mission, we’re using this technology to fill a critical need: giving the warfighter an additional outlet for fast, reliable communication and data transmission."
The Integrated System Engineering Team included members from AeroAstro, Air Force Research Laboratory, Air Force Space and Missile Systems Center, APL, ATK Space, Ball Aerospace and Technologies, Boeing, Design Net Engineering, General Dynamics AIS, Microcosm, Microsat Systems Inc., Massachusetts Institute of Technology Lincoln Laboratory, NRL, Orbital Inc., Space System Loral, and Raytheon.
The Office of Naval Research sponsored development of the TacSat-4 payload and is funding the first year of operations; the Office of the Secretary of Defense/Director of Defense Research and Engineering funded the spacecraft bus standards. The Operationally Responsive Space Office funded the launch.