While much of the nascent civilian unmanned aircraft industry looks at ways to optimize small unmanned aerial systems (UAS) for specific tasks such facility security, infrastructure inspection, or precision agriculture, a New Mexico-based aerospace startup is thinking bigger and longer-term.
Titan Aerospace, a one-year-old venture-backed aircraft designer, last week unveiled its Solara 50 and Solara 60 unmanned aircraft. These are two massive solar-powered, high-altitude vehicles the company plans to send aloft for weeks, months, and eventually years at a time without ever having to land.
Titan doesn’t refer to these concept aircraft as “drones” or by the industry-preferred “unmanned aerial system,” but instead calls them “atmospheric satellites” for their ability to remain aloft for extended periods of time just as orbital satellites do. The company hopes to provide a sub-$2 million platform that governments, private industry, and research institutions can put high into the atmosphere for extended periods of time for a fraction of the cost of a space satellite.
The idea is that an atmospheric satellite can conduct most of the same operations as an orbital one: atmospheric observation and weather monitoring, communications relay, oceanographic research, and earth imaging. Other operations are impractical for space satellites, such as border security, maritime traffic monitoring and anti-piracy operations, disaster response, or agricultural observation. And with continuous flight time of up to five years, Solara’s aircraft would have endurance on par with many small satellites, making them a more attractive option for a range of these applications (not to mention that if a sensor or instrument goes down, you can land and relaunch).
“If you have to go up to the satellite and rent that service, that’s a lot of money,” says Dustin Sanders, Titan’s chief electrical engineer. “And launching a satellite, that can be in the billions of dollars. We’re trying to do a single-million-dollar-per-aircraft platform. And the operation cost is almost nothing — you’re paying some dude to watch the payload and make sure the aircraft doesn’t do anything stupid.”
Other long-endurance solar UAS concepts — including Aerovironment’s (AVAV) Global Observer and QinetiQ’s Zephyr, a demonstrator for a Boeing (BA) concept — have had little success in generating the kind of long-term atmospheric satellite Titan envisions, but the company’s engineers think they’ve worked around some of the thornier problems that have grounded previous efforts. For one, 160-foot-plus wingspans of the Solara 50 and Solara 60 will be covered edge-to-edge with advanced solar cell technology that will provide enough energy for both day and night flight (batteries will store power during the day for use at night) with enough left over to power up to 70 pounds of sensors and instruments.
But perhaps the most important part of the formula is not how it will fly, but where. To sustain such long flight durations, the aircraft will operate in an atmospheric sweet spot known as the tropopause, a zone at roughly 65,000 feet (or more than 12 miles) above sea level where winds are generally less than 5 knots. In this relative calm far above any turbulence or weather that would otherwise challenge its flight capabilities, Solara could linger for up to five years, Titan engineers say. It doesn’t hurt that the tropopause resides far above the weather that can damage conventional aircraft or, more critically for Solara, block out the sun.
With rather simple mechanical systems and enough solar power to run them indefinitely, the thing limiting flight duration right now is the batteries themselves, Titan engineers say, which deteriorate over time and must be swapped out every few years. To prove it, the company has two fifth-scale test aircraft currently conducting test flights and — pending a round of Series B funding — will have a full-sized prototype in the air by spring or summer of next year.
By the time the company delivers its first aircraft — which could happen as soon as the end of next year — solar cell and battery technology may have improved such that the aircraft can extend their flight durations or carry even more payload, Sanders says. “We’re focusing on the simplest, most lightweight solution for this and trying not to get overly complicated,” he says. “That’s really the key to keeping this thing affordable as well as to enable it to stay up there for years.”
Of course much of Titan’s success, at least in the U.S., hinges on the FAA clearing the aircraft to fly in the national airspace. While rules governing UAS integration into the national airspace are pending (delivery of a regulatory framework is slated for 2015), the rules attached to larger UAS like the planned Solara are expected to be fairly strict.
But Sanders and company aren’t particularly worried. Titan has been working closely with the FAA through its design process, and anyhow the only part of that multi-year duration the FAA is technically concerned with is the initial climb. Class A airspace ends at 60,000 feet in the U.S.; above that the FAA doesn’t regulate, Sanders says (that’s roughly twice the altitude that commercial airliners operate).