“This is the last S-3B flying today anywhere in the world. It’s been a workhorse for NASA, but we just can’t source its unique parts anymore,” Jim Demers, Glenn’s Flight Operations Manager
When the US Navy withdrew its S-3B Viking fleet from active service in 2009, a few aircraft kept flying. As noted by Nancy Smith Kilkenny of NASA’s Glenn Research Center in her article “NASA Retires a Research Workhorse,” one S-3B at NASA Glenn in Cleveland continued to fly almost daily as a research aircraft. Acquired by NASA in 2004, it supported a wide range of flight research missions for the next 16 years. Now this S-3B Viking is preparing for its final journey to the San Diego Air & Space Museum in California, where it will retire on display and help educate visitors about its significant contributions to both the US Navy and NASA.
“This is the last S-3B flying today anywhere in the world,” says Jim Demers, Glenn’s Flight Operations Manager. “It’s been a workhorse for NASA, but we just can’t source its unique parts anymore.”
The VSX (S-3) program began in 1968, and in 1969, Lockheed received the contract to develop the Navy’s new carrier-based, fan-powered antisubmarine warfare aircraft. The design incorporated the latest advances in sensors and computer-based data processing, display, and weapons control systems, enabling the four-person crew to respond effectively to emerging submarine threats. The S-3 Viking—nicknamed “Hoover” by its crews—replaced the older, piston-engine S-2 Tracker.
The S-3A airframe was modified to perform additional missions, continuing a tradition of versatility long associated with its S-2 predecessor. The upgraded S-3B variant featured enhanced technology that extended radar detection range and improved target classification, incorporated more advanced acoustic processing and support systems, and added the capability to carry Harpoon missiles.
Equipped with its APS-137 Inverse Synthetic Aperture Radar (ISAR), ALR-67 Electronic Surveillance Measures (ESM) suite, and the ability to employ Harpoon missiles, the Viking was vital for surveillance, reconnaissance, and targeting, helping maintain a comprehensive sea-control picture for both naval and joint forces. After the A-6 was retired, the Viking also became the carrier group’s primary organic aerial refueling platform and a key asset for offensive mining operations. In addition, it continued to support Antisubmarine Warfare (ASW), particularly in coastal and near-shore waters.
In 2006, NASA’s S-3B Viking was completely overhauled for use in flight research. All of its weapons systems were removed and replaced with civilian avionics, GPS, and satellite communications equipment to support flight communications studies. One of its key achievements was helping NASA’s aeronautics researchers develop communications standards that the Federal Aviation Administration (FAA) can use to ensure unmanned aircraft systems operate safely in U.S. airspace.
“This old aircraft has been a huge part of ushering in the future of aviation,” says Mike Jarrell, lead of NASA’s Command and Control project. “The S-3B has been a perfect match for our research. It has a nice flat bottom where we can mount a variety of antennas; it flies steady and goes low and slow so we can communicate with ground stations.”
Jarrell notes that the S-3B has flown research missions across virtually every type of terrain in the national airspace, including mountains, hills, open water, plains, and deserts. The findings from these flights have provided NASA, the FAA, and industry partners with a clear path toward secure, reliable command-and-control radio links for communicating from the ground to unmanned aircraft systems.
The S-3B also conducted research flights to track algal bloom growth in Lake Erie and to develop hyperspectral imaging tools that provide university researchers with more precise data for their studies. These hyperspectral sensors, mounted on the underside of the aircraft, capture a broad range of light wavelengths to distinguish different types of harmful algal blooms in the water.
“The S-3B gave us the flexibility to fly at different altitudes to image large swaths of Lake Erie and other bodies of water,” says Roger Tokars, an elliptical and optics engineer with NASA Glenn. “The other advantage was the aircraft’s inertial navigation system that helped us calibrate our equipment for better geo-referencing data.”
NASA will continue its advanced air mobility communications research using a T-34 Mentor aircraft, as it develops new standards to recommend to the Federal Aviation Administration.
Photo by NASA and Louis DePaemelaere, Retired Master Sergeant, USAF
