“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 retired its fleet of S-3B Vikings from active duty in 2009, not all of them were grounded. Actually, as explained by Nancy Smith Kilkenny, NASA Glenn Research Center, in the article NASA Retires a Research Workhorse, at NASA’s Glenn Research Center in Cleveland, one S-3B was being used almost daily as a flight research aircraft. Acquired in 2004 and flown for the next 16 years on a variety of research missions, this S-3B Viking is about to fly off into the sunset and retire at the San Diego Air and Space Museum in California where it will be used to educate the public about its important role in the US Navy and at 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 program (S-3) started in 1968, and, in 1969, Lockheed was awarded the contract to develop the Navy’s new carrier-based, fan-powered ASW aircraft. It was designed to incorporate the latest concepts in sensors and in computer-based data processing, display and weapons control systems, and in enabling the four-man crew to effectively deal with the anticipated submarine threat. The S-3 Viking (dubbed Hoover by its aircrew) replaced the old reciprocating-engine-powered S-2 Tracker.
The S-3A airframe has been adapted to other roles–a characteristic for which its S-2 predecessor has long been noted. The improved S-3B version incorporated improved technology for increased radar detection range and classification, advanced acoustic processing, and support measures, and has Harpoon missile capability.
With its APS-137 Inverse Synthetic Aperture Radar (ISAR), ALR-67 Electronic Surveillance Measures (ESM) system and Harpoon missile capability, the Viking played a critical surveillance, reconnaissance and targeting role in maintaining the sea control picture for naval and joint forces. Additionally, with the retirement of the A-6, the Viking became the principal organic tanking platform for the battlegroup and a mainstay in offensive mining. It also contributed to Antisubmarine Warfare (ASW), especially in the littoral regions.
NASA’s S-3B Viking was completely reconfigured in 2006 for flight research purposes. All weapons systems were removed and replaced with civilian avionics, GPS, and satellite communications systems to conduct flight communications research.
One of its major contributions was helping NASA’s aeronautical innovators define communications standards that the Federal Aviation Administration (FAA) can apply to the unmanned aircraft systems for safe operation in US 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 antenna; it flies steady and goes low and slow so we can communicate with ground stations.”
Jarrell adds that the S-3B has conducted research flights in every terrain in the national airspace including mountains, hills, over water, plains, and deserts. The results of the flight research have given NASA, the FAA, and its commercial partners a path to secure, reliable command-and-control radios used for communication from the ground to unmanned aircraft systems.
The S-3B also flew research flights to monitor algal bloom growth in Lake Erie and develop hyperspectral imaging equipment to provide more accurate data for university scientists studying the problem. The hyperspectral imagers, mounted to the aircraft’s underbelly, analyze a wide spectrum of light to identify the 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’s communications research in advanced air mobility will continue using a T-34 Mentor aircraft as new standards are developed to recommend to the Federal Aviation Administration.
Photo credit: NASA and Louis DePaemelaere, Retired Master Sergeant, USAF