Friday, February 19, 1999

NASA has big
ideas for Kauai
missile range

Plans are to test high-tech
unmanned aircraft there
'well into the future'

By Anthony Sommer


BARKING SANDS, Kauai -- After two years of record-smashing flights over Kauai by Pathfinder craft, NASA is looking at bringing a parade of high-tech unmanned aircraft to the Navy's Pacific Missile Range Facility for testing.

"We're planning to use PMRF well into the future," said John Del Frate, former project manager of the Pathfinder program and now head of the Centurion program.

The overall program is called Environmental Research Aircraft and Sensor Technology , and the goal is to create a variety of airplanes that can fly above the weather for days, weeks or months carrying science packages capable of monitoring everything from air pollution to leaks in agricultural water systems.

The lure of the Pacific Missile Range is the Navy's 42,000 square miles of open ocean northwest of Kauai. Nowhere else in the United States is there such a vast area free of the commercial aircraft that have limited operations at NASA's Dryden Flight Test Research Center at Edwards Air Force Base, Calif.

And with the new equipment being installed to test the Navy's Theater Ballistic Missile Defense system -- which promises to have the fastest missiles in the world -- few other places can match the base's tracking, telemetry and communications capabilities.

Not that speed counts in research aircraft. No "Right Stuff" is required here, in fact no stuff at all.

The aircraft are flown by pilots watching live video feeds from the airplanes and seated in office chairs inside surplus military communications vans beside the runway. "Uninhabited Aircraft" is the term in NASA jargon, and the goal is to conduct science experiments for what the space agency terms "extreme duration."

Powered by electric motors wired to photovoltaic solar cells, Pathfinder was only one variant, a step toward what NASA hopes will be an "eternal airplane" capable of remaining aloft indefinitely.

Next up is the dual-turbocharged ALTUS II, due to arrive in April to conduct research on how clouds affect solar radiation, part of a larger global warming study. Ten flights are scheduled. Tentatively set for flights next winter is Perseus B, which is powered by a conventional piston engine using liquid oxygen at high altitudes.

Centurion, the follow on the Pathfinder solar plane, will be up next. It was originally scheduled to fly at Kauai next summer but now faces a delay of a year or more.

After that could come what NASA calls the "Mars Airplane," designed to be carried by rocket to the Red Planet and flown in leisurely excursions over its surface.

"With the exception of Pathfinder, we won't be testing the envelope on Kauai," Del Frate said. "The designs all will have gone through extensive test flights at Dryden."

The reasoning is that if something goes wrong and NASA has to land a crippled aircraft suddenly, anywhere on Edwards' massive, flat, dry lake bed will do to get the airplane back in one piece. If they have to bring a plane down at the Pacific Missile Range, it's going to end up in the ocean.

Rather than proving the airplane design, the testing at the Pacific Missile Range will involve the second goal of Environmental Research Aircraft and Sensor Technology: marrying proven aircraft to science packages and testing how well they collect data.

A closer look

Here's a rundown of various high-tech unmanned aircraft:


bullet Pathfinder: On July 7, 1997, the original six-motor Pathfinder set a world altitude record for propeller-driven aircraft: 71,500 feet. It then spent much of the rest of the summer snapping spectacular infrared high-altitude photographs of Kauai.

Pathfinder Plus -- the same aircraft with longer wings and two more motors -- set another world record Aug. 7, 1998, when it soared to 80,201 feet.


bullet Altus II: NASA is trying to play catch-up after a fire on the research aircraft last week. It is still on its way to Kauai, but it's a close call whether it will be ready this spring or have to wait until fall.

The timing is somewhat critical because the experiments ALTUS II is to perform involve the effect of cirrus clouds on solar radiation. Cirrus clouds are rare above Kauai in the summer. Further delay could push the tests back to this fall.

One of the questions Sandia National Laboratory hopes to answer with the tests is whether Earth has a natural defense mechanism that places limits on global warming.

The yet-to-be-proven concept is that if the Earth warms more and more, increasing numbers of clouds will form from evaporation of the oceans. At some point, the cloud cover may block solar radiation to the extent that it will halt the warming, said Sandia spokeswoman Nancy Garcia.

So far, ALTUS II has reached only 43,500 feet in test flights, well below the 65,000-foot target. It holds the world record for sustained flight by a remote-controlled aircraft: 26 hours.

bullet Perseus B: Vince Nashina, NASA's project manager on Kauai, said he received word Tuesday that plans are under consideration to bring the Perseus B to the Pacific Missile Range next winter.

The goal of the Perseus program is to design an aircraft that can conduct atmospheric sampling at altitudes up to 65,000 feet.

The Perseus design uses turbochargers to provide oxygen to the engines. But unlike ALTUS II, Perseus B relies on a supply of liquid oxygen that is sprayed into the cylinders to allow it to fly at high altitudes.

Perseus B has been flown higher than ALTUS II -- 60,000 feet last June -- but its flight duration has been limited. Engineers are testing external fuel tanks that would allow it to stay aloft for at least 24 hours.


bullet Centurion: Like the solar-powered Pathfinder, Centurion is a flying wing with no fuselage. Its instruments are carried in pods beneath the wings, and the photovoltaic solar panels are mounted on top.

Pathfinder Plus is big: 121 feet wide, comparable to the DC-9s flown by Hawaiian Airlines and the Boeing 737s used by Aloha.

Centurion is bigger: 206 feet wide, about the wingspan of a Boeing 747.

Centurion was designed to carry a science package of 100 pounds to 100,000 feet or a 600-pound package to 80,000 feet.

And it was designed to stay aloft for weeks at a time.

After spectacular low-altitude test flights on battery power in November and December, Centurion was scheduled to fly from Kauai this summer.

NASA is looking at increasing the wing span from 206 feet to 260 feet. That would make it the size of Helios, the still-on-the-drawing-boards successor to Centurion.

The Stretch Centurion will be tested at Edwards next summer and brought to Kauai in the summer of 2000 -- maybe. The best time to test a solar airplane is in the summer when there is maximum daylight.

NASA hopes to bring Helios to the Pacific Missile Range in 2002 or 2003.

bullet Mars Airplane: NASA concedes this would be a long shot, but it is possible the proposed Mars Airplane could come to the missile range for testing.

NASA Administrator Dan Golden recently gave his agency what NASA officials admit is an "out of the box" mission of coming up with an airplane that could be flown to Mars by rocket and then used, possibly on multiple flights, for low-altitude surveys of Earth's nearest planetary neighbor.

And he wants to do it by 2003, the centennial of the Wright brothers' first flight.

Right now, no one even knows what the Mars Airplane will look like.

"It's not inconceivable that we would end up with something based on the designs we've already proven on Pathfinder," said John Del Frate, former project manager of the Pathfinder program. "And it's possible it could be tested in the same place where we've flown Pathfinder."

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