PMRF to launch commercial UAV project

The U.S. Navy’s Pacific Missile Range Facility (PMRF) at Barking Sands is once again home to a history-making, record-breaking, solar-powered unmanned aerial vehicle (UAV) flight series.

The Pathfinder Plus (first scheduled to launch on Saturday, June 22, but now on wait until wind conditions improve) and its crew also bring to PMRF the world’s first experiments in equipping an UAV with a payload of commercial telecommunication devices for broadcast from the stratosphere.

These experiments herald an extraordinary collaboration between science and business, while ushering in the next generation of global networking technology. While the Pathfinder Plus isn’t “going for the gold” as far as attaining an altitude record is concerned, the potential business applications of this project are staggering, according to involved commercial interests.

According to PMRF Program Manager Wolfgang Kneidl, the latest flurry of UAV activity at Barking Sands is focused on aircraft performance studies to specifically refine the flying capabilities of the Pathfinder Plus to accommodate various types of commercial payloads.

“This summer’s UAV test flights at PMRF will demonstrate marketable applications of unmanned, solar-powered aircraft, rather than attempting to break any altitude records like previous UAVs tested at Barking Sands,” he said.

The goal of the Next-Generation Telecommunications Demonstration is to display how two telecommunication systems, expected to become gargantuan businesses in the coming decade, will function.

These demos include digital television broadcast (DTV), and testing a payload of third-generation cell phone standard technology, called International Mobile Telecommunications-2000 (IMT-2000), which is capable of transmitting voice, data, Internet and combined picture phone signals over a normal-sized cell phone.

The latter tests are using off-the-shelf mobile phones.

“NASA has made the Pathfinder Plus available for these experiments due to the agency’s interest in further maturing this class of aircraft, and showcasing its capabilities for real work,” said NASA solar-powered aircraft manager John Del Frate.

The Pathfinder Plus is designed and operated by AeroVironment Inc., a California-based aerospace engineering company, through NASA’s environmental research and sensor program. NASA also sponsored the aircraft’s development.

The Next-Generation Telecommunications Demonstration is being co-funded by the Japanese government’s Communications Research Laboratory (CRL), the research wing of the Japanese government’s Post and Telecommunications Ministry, its affiliate, Telecommunications Advancement Organization of Japan (TAO), and Sky Tower.

Also participating in the project is the Japanese Stratosphere Communications, Inc. corporation. Sky Tower is a subsidiary of AeroVironment that supplies global commercial telecommunications infrastructure based on solar-electric aircraft technology.

“These demos are a significant milestone for Sky Tower,” explained Stuart Hindle, Sky Tower’s vice president of strategy and business development.

“It is the first time in the world that commercial telecommunication applications have been delivered from a platform operating at over 65,000 feet in the stratosphere.”

Hindle expects the tests to show that UAVs will provide valuable infrastructure solutions.

In addition to testing the feasibility of flying an UAV with a commercial payload, scientists are currently working on technology to extend the time aloft for solar-powered aircraft like the Pathfinder Plus – an absolute necessity in the world of business, where uninterrupted broadcast signal transmissions are crucial.

“NASA and AeroVironment have been designing and testing very-lightweight, fuel-cell-based systems that can be used to provide electric power to the UAVs, so that they can maintain their altitude after daylight hours, when the sun – our main power source – goes away,” said Del Frate.

“Presently, when the sun goes down, a solar-powered aircraft can only glide, which means it’s coming down. Although we carry some batteries on board for power, they are primarily for the aircraft landing, and for emergencies,” said Del Frate.

According to said Yuichiro “Gene” Nishi, president of Japan Stratosphere Communications, Inc. of Tokyo, the essence of the project is to validate the concept of using the Pathfinder Plus as a High Altitude Platform Station (HAPS).

“The beauty of this approach is that we are using equipment that you would buy at Radio Shack,” said Nishi.

By loading a UAV with a cache of ordinary telecommunications gear, scientists and engineers hope to eclipse current, limited technological capabilities, and the problems associated with satellite signal transmission.

And, the system is expected to utilize and maintain compatibility with existing, earth-based infrastructure.

“What HAPS will do is take what we already have – cell phones, TV sets and antennas, terrestrial repeater sites, cable lines and other telecom infrastructure – and multiply their transmission and receiving efficiency a thousand fold,” said Nishi.

“When the package is perfected, roaming only in certain directions, scaling tall buildings, or dodging large mountains will no longer be the only way to get clear TV broadcasts and audible cellular signals,” Nishi added.

The Pathfinder Plus is capable of flying in a tight, figure-eight pattern above a crowded city, thus enabling the HAPS to send unobstructed signals in a straight line from directly above the consumer’s area.

“This is a perfect solution for congested places like Tokyo, where TV antennas only pick up a direct signal. Every time a new high rise is built, it blocks out everything (all communication signals) in its shadow,” said Nishi.

The Pathfinder Plus was selected for the tests instead of the Helios Prototype because of availability. The Helios broke world altitude records last summer at PMRF, and is currently undergoing upgrades to install a fuel-cell system for providing multi-day flights at AeroVironment’s Design Development Center in Simi Valley, Calif.

“We are very excited to have the opportunity to demonstrate that the Pathfinder can act as a reliable and secure, 12-mile-high tower for the communication payloads built by our Japanese friends,” said Bob Curtin, vice president of AeroVironment.

After the 1997 test runs at Barking Sands, the Pathfinder was upgraded to the Pathfinder Plus, with modifications including longer wings, improved motors, and more efficient solar arrays.

During the summer of 1998, Pathfinder Plus was flown at PMRF to a then-record altitude of 80,201 feet.

Armed with information and technology provided by the Pathfinder program, work began on the Helios, which was refined and tested at PMRF last summer.

The Helios flew to a new, certified world altitude record of 96,863 feet on Aug. 13, 2001.

“There are major differences between the Helios tests (of last year) and the Pathfinder Plus this year,” said Del Frate. “Instead of trying to figure out how to fly high, the focus is on demonstrating that this type of aircraft is, in fact, a workhorse that can do valuable jobs or, in other words, ‘earn its keep,’ ” said Del Frate.

He added that PMRF was selected for the tests because of the high levels of sunlight, the wide-open airspace, and lack of encroachment by radio frequencies and air traffic.

“The impetus for the program was always to fly high, and fly for weeks or months at a time. Pathfinder’s first flights in the early ’80s demonstrated that solar-powered, remotely controlled flight was possible,” said Del Frate.

“But the technology necessary for extreme altitude and extreme duration unmanned flights just wasn’t up to speed at that point, so the Pathfinder went into mothballs until 1992,” he continued.

“The Pathfinder underwent modifications, and set a high-altitude record of 80,000 feet in 1998, then shared the stage with several other NASA unmanned vehicles including the Altus, the Perseus A, Perseus B, Proteus, and the Helios,” he noted.

“Last year’s high-profile, record-breaking tests of the Helios at Barking Sands, where it raised the world altitude record for an unmanned solar vehicle, and for any non-rocket propelled aircraft, could not have been accomplished without the ground-breaking work of the Pathfinder Plus.”

The Pathfinder Plus and the Helios are the only flying, non-stationary, solar-powered, high-altitude UAVs in existence that are capable of reaching the stratosphere today.

Testing the performance of telecommunications equipment in the stratosphere is logical because, at 60,000 to 160,000 feet, the stratosphere experiences no intrusion from commercial jets, which cruise at altitudes of about 36,000 feet.

And, unlike other regions of the sky, the stratosphere is above all interfering weather conditions, and experiences very stable winds. The stratosphere is also much closer to Earth than the average satellite orbiting at around 800,000 feet.

Shearing the proximity of telecom equipment between the user and the signal station by 735,000 feet not only decreases power requirements, it also will result in a significant decrease in signal delays, currently a common problem with satellite transmissions.

Until the Helios proved that a solar-powered UAV could achieve and sustain record-breaking altitudes, the HAPS concept was only a theory waiting to be tested. When Nishi saw the potential for mass communication usage and global benefits, he contacted NASA at the Japanese Embassy in Tokyo.

“When we started maturing the solar-powered aircraft, applications like the HAPS concept and telecommunications were exactly what we envisioned for these environmentally friendly planes,” said Del Frate. “It is almost like a marriage made in heaven.”

Authorization to use the frequency spectrum for the multiple telecommunications tests this summer on Kaua’i was provided by the Federal Communications Commission (FCC) in the form of an Experimental Special Temporary Authorization.

Due to heightened security in the wake of the September 11, 2001 terrorist attacks on America, no public viewing of this year’s solar-powered aircraft flights will be permitted.

Telecommunication experimental flights are set for June and July. Experiments with the Pathfinder Plus serving as an image acquisition platform for precision agricultural management will be conducted in September over the Kauai Coffee Company fields from ‘Ele’ele to Po’ipu.

The company’s acreage makes it the largest coffee-growing region in the United States.