WASHINGTON — An experimental U.S. military satellite now undergoing final launch preparations will analyze the composition of ground features while demonstrating a new mode of operations that empowers deployed forces to direct how spacecraft are employed as they pass overhead.

The TacSat-3 satellite already has fulfilled part of its mission, which was to provide experience in developing low-cost satellites that can be fielded relatively quickly, according to Peter Wegner, director of the Pentagon’s Operationally Responsive Space (ORS) Office.

Five years in the making, TacSat-3 is the second in a series of experimental craft intended to demonstrate the ORS concept. The satellite was delivered to NASA’s Wallops Island, Va., launch facility March 28 and is on schedule for a May 5 launch aboard a Minotaur 1 rocket, Thomas Cooley, the TacSat-3 program manager at the U.S. Air Force Research Laboratory, said in an interview.

The Air Force Research Laboratory led the development of the satellite along with the Pentagon’s ORS Office, Office of Force Transformation and Office of Naval Research, and the U.S. Army Space and Missile Defense Command.

The main instrument on board the 400-kilogram satellite is the Advanced Responsive Tactically Effective Military Imaging Spectrometer (ARTEMIS) built by Raytheon Space and Airborne Systems of El Segundo, Calif. ARTEMIS is being touted as the military’s first space-based hyperspectral sensor. Also on board are the Ocean Data Telemetry Micro satellite link that will collect data from sea-based buoys and the Space Avionics Experiment that will validate plug-and-play avionics capabilities on orbit for the first time.

Traditional panchromatic, or black and white, satellite imagery is captured using a single band of the electromagnetic spectrum, while color satellite imagery is created by layering three or four bands of spectral data on top of one another. Hyperspectral sensors break reflected light into hundreds of spectral bands, which can reveal information about the physical or chemical properties of objects and surfaces.

With the understanding that any given material, whether it is granite, polyester or clay, absorbs different wavelengths of light, data taken in hundreds of spectral bands can be analyzed to determine what substances are present. This can help analysts distinguish between tanks and decoys, for example.

During its scheduled year of operation, TacSat-3 also will demonstrate a direct tasking method not often employed by the military. During the experiments, Army users in the field will directly task the satellite while it is within their field of view, rather than send a request to controllers located elsewhere. The satellite will orient itself to capture the requested data, process it on board and beam it directly back to the user’s terminal, all in the span of 10 minutes during the same orbital pass.

The development of TacSat-3 incorporated lessons from TacSat-2, which launched in 2006, Wegner said in an interview. Whereas TacSat-2 relied heavily on inexpensive off-the-shelf components, TacSat-3 was developed with an eye toward fielding a semblance of an operational capability, Wegner said. This approach entailed measures such as space qualifying the command data-link radio, which was not done for TacSat-2, and working through the entire concept of operations for the mission.

The initial goals for TacSat-3 were ambitious. The program was intended to cost $50 million, including launch, and integration of the instruments with the spacecraft and testing were planned to be condensed to 60 days. A series of technical difficulties and supply-chain issues delayed the satellite for more than a year, however, and the final price tag will be around $88 million, although that sum also reflects various requirements changes made along the way, Cooley said.

“We have resolved all of those issues, and we now have a fully functional spacecraft,” Cooley said.

While the military has not announced plans to build any follow-on hyperspectral satellites, Cooley believes TacSat-3 will prove the technology to be viable and affordable. Based on the lessons from TacSat-3, follow-on missions could track more closely with the ORS office’s stated goal of procuring satellites for no more than $40 million and launches for no more than $20 million, Cooley said.

The next satellite in the series is TacSat-4, which is managed by the Naval Research Laboratory in Washington. That satellite features several experimental telecommunications payloads and is expected to launch in September aboard a Minotaur 4 rocket.