Navy Launches UHF-comm TacSat-4 'Microsat'

The Navy has launched an experimental spacecraft to test new SATCOM techniques. The TacSat-4 uses small, relatively low cost satellite and launch vehicle technology. It will be used to provide UHF communications to troops on the ground using their existing radios and a wide-band "MUOS-like" channel for early testing. The small satellites will operate in a highly elliptical orbit, with an apogee of 12,050 kilometers and a 4-hour orbital period, providing close to continuous global communications on the move to the battlefield and access to mountainous regions that previously had problems with communications. While it seems likely that enthusiasts with the right equipment will be able to receive transmissions from the satellite, I would expect them to be encrypted or use spread spectrum technology to make the communications impossible to decipher.

The satellite was launched from the Alaskan Aerospace Corporation's Kodiak Launch Complex aboard a Minotaur IV+ launch vehicle. It was built by the Naval Research Laboratory and John Hopkins University Applied Physics Laboratory.

The satellite weights 450 kg and includes a 1,000 watt solar array and a 12 foot diameter high gain payload antenna. It has 10 UHF channels. More information is available in the Tactical Microsatellite (TacSat) fact sheet.

How small could satellites be and still do useful work? Last month IEEE Spectrum covered Exploring Space with Chip-sized Satellites.

Doug Lung

Doug Lung is one of America's foremost authorities on broadcast RF technology. As vice president of Broadcast Technology for NBCUniversal Local, H. Douglas Lung leads NBC and Telemundo-owned stations’ RF and transmission affairs, including microwave, radars, satellite uplinks, and FCC technical filings. Beginning his career in 1976 at KSCI in Los Angeles, Lung has nearly 50 years of experience in broadcast television engineering. Beginning in 1985, he led the engineering department for what was to become the Telemundo network and station group, assisting in the design, construction and installation of the company’s broadcast and cable facilities. Other projects include work on the launch of Hawaii’s first UHF TV station, the rollout and testing of the ATSC mobile-handheld standard, and software development related to the incentive auction TV spectrum repack.
A longtime columnist for TV Technology, Doug is also a regular contributor to IEEE Broadcast Technology. He is the recipient of the 2023 NAB Television Engineering Award. He also received a Tech Leadership Award from TV Tech publisher Future plc in 2021 and is a member of the IEEE Broadcast Technology Society and the Society of Broadcast Engineers.