DARPA recently released a Request for Information (ROI) on “concept feasibility, unique and enabling platform technologies, system architectures, concepts of operation, modeling and simulation, potential demonstration platforms and approaches, and reusable low-cost delivery vehicle (UAS) platform concepts” for an airborne mothership for small unmanned aerial vehicles.

The agency wants to look at proposals that would employ an existing large aircraft “that, with minimal modification, could launch and recover multiple small unmanned systems from a standoff distance,” according to the announcement.

“We want to find ways to make smaller aircraft more effective, and one promising idea is enabling existing large aircraft, with minimal modification, to become ‘aircraft carriers in the sky’.”

A follow-up DARPA release explained that while small UAS can fly some intelligence, surveillance, and reconnaissance (ISR) missions, eliminating the risks to pilots of manned aircraft penetrating enemy airspace to perform such missions, existing UAS are too slow, and lack the range and endurance to perform such missions.

“We want to find ways to make smaller aircraft more effective, and one promising idea is enabling existing large aircraft, with minimal modification, to become ‘aircraft carriers in the sky’,” said Dan Patt, DARPA program manager. “We envision innovative launch and recovery concepts for new UAS designs that would couple with recent advances in small payload design and collaborative technologies.”

While unmanned aircraft have been launched from motherships for some time, DARPA has added the requirement of the smaller unmanned aircraft returning to the mothership. Aircraft-carrying aircraft concepts, however, have been taking to the air for a century. Using aircraft as motherships to other aircraft is far from a new idea, with a British “parasite” Bristol scout launching from a Felixstowe flying boat in 1916, and several experiments with lighter-than-air craft carrying single aircraft were carried out by both sides during World War I.

DARPA, however, is willing to study proposals, and it may be that technology has progressed to the point that the flying aircraft carrier’s time has come.

The U.S. Navy airships Akron (ZRS 4) and Macon (ZRS 5) later carried out experiments as flying aircraft carriers with Curtiss F9C Sparrowhawk fighters during the 1930s, and the Russian Zveno Project paired Tupolev bombers with smaller “parasite” fighters attached to the upper wing or hanging beneath during the same era. A few aircraft configured this way carried out attacks on the Germans during World War II. The Germans themselves experimented with parasite and composite aircraft during World War II (the “Mistel” aircraft and other schemes), and the Japanese hung Ohka rocket-powered suicide aircraft beneath “Betty” bombers.

After the war the U.S. Air Force experimented with a number of methods of pairing fighters with B-36 bombers, both F-84 Thunderjets and Thunderflash, and the notorious XF-85 Goblin. A more modern take on the mothership principle was the ill-fated pairing of a two-seat A-12 (designated M-21) carrier aircraft with a pylon on its back upon which a D-21 drone piggybacked.

All of these projects encountered little if any success.

DARPA, however, is willing to study proposals, and it may be that technology has progressed to the point that the flying aircraft carrier’s time has come.

According to the DARPA press release, the three specific primary areas that responses must address are:

1. System-level technologies and concepts that would enable low-cost reusable small UAS platforms and airborne launch and recovery systems that would require minimal modification of existing large aircraft types. This area includes modeling and simulation as well as feasibility analysis, including substantiating preliminary data if available.
2. Potentially high-payoff operational concepts and mission applications for distributed airborne capabilities and architectures, as well as relative capability and affordability compared to conventional approaches (e.g., monolithic aircraft and payloads or missile-based approaches). DARPA hopes to leverage significant investments in the area of precision relative navigation, which seeks to enable extremely coordinated flight activities among aircraft, as well as recent and ongoing development of small payloads (100 pounds or less).
3. Proposed plans for achieving full-system flight demonstrations within four years, to assist in planning for a potential future DARPA program. DARPA is interested not only in what system functionality such plans could reasonably achieve within that timeframe, but also how to best demonstrate this functionality to potential users and transition partners. These notional plans should include rough order-of-magnitude (ROM) cost and schedule information, as well as interim risk reduction and demonstration events to evaluate program progress and validate system feasibility and interim capabilities.

Responses, limited to 8-page proposals, are due no later than Nov. 26, 2014.