The US Defense Advanced Research Projects Agency (DARPA) has moved to a third and final stage of an effort to launch medium-altitude long-endurance (MALE) unmanned aerial vehicles (UAVs) from US Navy’s relatively small surface ships like destroyers, frigates, and even freighters and expects an initial flight test in 2018.
The ultimate goal for a TERN UAV and launch system to enable persistent intelligence, surveillance, and reconnaissance (ISR) and strike capabilities with payloads as large as 600 pounds while operating at ranges as long as 900 nautical miles from a host vessel. The TERN program envisions a capability “like having a falcon return to the arm of any person equipped to receive it, instead of to the same static perch every time,” says Daniel Patt, the DARPA TERN program manager. “About 98 percent of the world’s land area lies within 900 nautical miles of ocean coastlines,” Patt explains. “Enabling small ships to launch and retrieve long-endurance UAVs on demand would greatly expand our situational awareness and our ability to quickly and flexibly engage in hot spots over land or water.
“Effective 21st-century warfare requires the ability to conduct airborne intelligence, surveillance and reconnaissance (ISR) and strike mobile targets anywhere, around the clock. Current technologies, however, have their limitations. Helicopters are relatively limited in their distance and flight time. Fixed-wing manned and unmanned aircraft can fly farther and longer but require either aircraft carriers or large, fixed land bases with runways often longer than a mile. Moreover, establishing these bases or deploying carriers requires substantial financial, diplomatic and security commitments that are incompatible with rapid response, “says DARPA.
The aircraft uses its own power to take off and land, forgoing the sort of pneumatic launcher and recovery system used by smaller at-sea UAVs such as the Insitu RQ-21 Blackjack. Condrey noted that the real engineering leap for TERN involves the navigation software needed to land on small deck space on a ship at sea.
“Technically it is [extremely] hard,” Dr Bradford Tousley, director of DARPA’s Tactical Technology Office, said during a 4 May briefing at AUVSI’s annual Xponential conference in New Orleans, Louisiana. The limited deck space and need to operate on high sea states make it especially difficult, Tousley noted. Northrop Grumman and DARPA have been working with a ‘tail-sitting’ flying-wing design that uses two counter-rotating propellers mounted on the aircraft’s nose.
Tern Program Navy’s New Warfighting concept: Distributed lethality
The Navy’s Surface Warfare leaders have announced a new warfighting concept, Distributed Lethality, “Our vision,” Vice Adm. Thomas Rowden, Pacific Fleet commander of naval surface forces, said, “is of naval forces employed in a widely dispersed, often autonomous manner with the ability to hold potential adversaries at risk, at range.” The DL concept addresses increasing the offensive firepower and lethality of the entire surface fleet—cruisers, destroyers, LCSs, future frigates, amphibious ships, and even replenishment ships.
However to enhance the offensive firepower and lethality of Small-deck ships such as destroyers and frigates they need to have their own unmanned air systems (UASs) to provide intelligence, surveillance and reconnaissance (ISR) and targeting data from extended ranges around the clock. Current state-of-the-art UASs, however, lacks the ability to take off and land from confined spaces in rough seas and achieve efficient long-duration flight.
“Distributed Surface Force operations must be underpinned by sufficient overhead ISR and communications relay/networking capability, especially in a satellite denied environment,” Bryan McGrath, managing director of The FerryBridge Group naval consultancy and deputy director of the Center for American Seapower at Hudson Institute testified before Congress. Helicopters and current unmanned aircraft just don’t have the range, endurance or payload. “Distributed Surface Operations require an organic, Medium Altitude Long Endurance UAV [unmanned aerial vehicle] capability.”
Tern Joint DARPA and Navy’s ONR program
In May 2014 DARPA and the Office of Naval Research (ONR) signed a memorandum of agreement making the program a joint effort—calling it Tactically Exploited Reconnaissance Node (Tern). Tern builds on DARPA’s TERN program and seeks to combine the strengths of both land- and sea-based approaches to supporting airborne assets. Tern, seeks to provide capabilities to forward-deployed small ships the ability to serve as mobile launch and recovery sites for medium-altitude, long-endurance unmanned aerial systems (UAS).
ISR and Strike capability
These systems could provide long-range intelligence, surveillance and reconnaissance (ISR) and other capabilities over greater distances and time periods than is possible with current assets, including manned and unmanned helicopters.
Ideally, Tern would enable on-demand, ship-based unmanned aircraft systems (UAS) operations without extensive, time-consuming and irreversible ship modifications. It would provide small ships with a “mission truck” that could transport ISR and strike payloads to very long distances from the host vessel. The solution would support field-interchangeable mission packages for both overland and maritime missions. It would operate from multiple ship types and in elevated sea states. Further, a capacity to launch and retrieve aircraft on small ships would reduce the need for ground-based airstrips, which require significant dedicated infrastructure and resources.
The two prime contractors selected by DARPA are AeroVironment, Inc., and Northrop Grumman Corp. The first two phases of Tern successfully focused on preliminary design and risk reduction.
The program is now entering Phase 3, with DARPA’s announcement of a contract award to a team led by Northrop Grumman to build a full-scale demonstrator system of a medium-altitude, long-endurance UAS designed to use forward-deployed small ships as mobile launch and recovery sites, DARPA said in an announcement. Northrop Grumman has received a $17.7 million contract modification as part of DARPA’s Tactically Exploited Reconnaissance Node, or Tern, program.
Phase 3 in particular focuses on design, fabrication and testing of a Tern prototype. The Tern Phase 3 design envisions a tailsitting, flying-wing aircraft with twin counter-rotating, nose-mounted propellers. The propellers would lift the aircraft from a ship deck, orient it for horizontal flight and provide propulsion to complete a mission. They would then reorient the craft upon its return and lower it to the ship deck. The system would fit securely inside the ship when not in use.
Initial ground-based testing, if successful, would lead to an at-sea demonstration of takeoff, transition to and from horizontal flight, and landing—all from a test platform with a deck size similar to that of a destroyer or other small surface-combat vessel.
“ONR’s and DARPA’s partnership on Tern continues to make rapid progress toward creating a new class of unmanned air system combining shipboard takeoff and landing capabilities, enhanced speed and endurance, and sophisticated supervised autonomy,” said Gil Graff, deputy program manager for Tern at ONR. “If successful, Tern could open up exciting future capabilities for Navy small-deck surface combatants and U.S. Marine Corps air expeditionary operations.”
“Moving to an unmanned platform, refocusing the mission and incorporating modern precision relative navigation and other technologies removes many of the challenges the XFY-1 and other prior efforts faced in developing aircraft based from small ships,” Patt said. “Tern is a great example of how new technologies and innovative thinking can bring long-sought capabilities within reach.”
Distributed, Disaggregated & Assured capability
“The design we have in mind for the Tern demonstrator could greatly increase the effectiveness of any host ship by augmenting awareness, reach and connectivity,” said Dan Patt, DARPA program manager. “We continue to make progress toward our goal to develop breakthrough technologies that would enable persistent ISR and strike capabilities almost anywhere in the world at a fraction of current deployment costs, time and effort.”
“Through Tern, we seek to develop and demonstrate key capabilities for enabling distributed, disaggregated U.S. naval architectures in the future,” said Bradford Tousley, director of DARPA’s Tactical Technology Office (TTO), which oversees Tern. “This joint DARPA-Navy effort is yet another example of how the Agency collaborates with intended transition partners to create potentially revolutionary capabilities for national security.”
The Navy needs something like the TERN, because an enemy like China or Russia will attack the satellites and datalinks that form the sinews of American military power. “If conflict results in the reduction of satellite communications and networking, ships operating distant from the carrier strike group will need the ability to generate these capabilities organically,” McGrath said.
US Naval S&T Strategy
The development of TERN is also in line with US Naval S&T strategy. The Office of Naval Research, has released its ” The Naval S&T Strategy ” to align S&T with naval mission and future capability needs, balance and manage the S&T investment portfolio , communicate the S&T vision and approach to senior decision makers, key stakeholders, partners, customers and performers. The capability gaps have been mapped into nine S&T focus areas that help align, balance and communicate the efforts between the warfighter, ONR and the S&T community.
One focus area is Power Projection and Integrated Defense, The vision is to strengthen and enhance naval power-projection capabilities and integrated layered defense by improving manned and unmanned platforms, payloads and weapons. This enables U.S. and our partner nations’ forces to complete missions at extended ranges within hostile environments by avoiding, defeating and surviving attacks
Another focus area is to achieve an integrated hybrid force of manned and unmanned systems with the ability to sense, comprehend, predict, communicate, plan, make decisions and take collaborative action to achieve operational goals. The employment of these systems will reduce risk for Sailors and Marines and increase capability.