Zephyr launched into record-setting history at YPG

In the early morning hours of July 9, an unmanned aircraft took to the skies at Yuma Proving Ground — and it's still flying today.

The Zephyr unmanned aircraft has a sleek wing equal in height to a seven-story building. It is covered with solar panels, and two modest propellers jut from its center.

The Zephyr's testers are hoping to break their own record for aerial longevity, set at YPG in 2008 when the craft flew in YPG's 2,000 miles of restricted airspace for more than three days without stopping. Not only are the aircraft's designers hoping to shatter this record, but they have taken the bold step of stating their intention to the National Aeronautic Association, the organization that verifies and officially certifies aerial records, which has sent an observer to witness the craft's launch. This time, they are hoping to stay aloft for 14 consecutive days.

With such ambitious goals, testers want launch conditions to be as ideal as possible. “We've been waiting for the best opportunity for a clear weather window,” said Jonathan King, the Zephyr's project manager. “This is the only aircraft of this type in existence and this is its first flight, so we are being very cautious.”

“Getting the craft from ground level to the target altitude is the most critical point,” added YPG test officer John Penny. “It depends on the weather, but will probably take 10-12 hours to ascend to 70,000 feet.”

The Zephyr

“The idea of the Zephyr is to complement satellites,” King explained. “It is by orders of magnitude less expensive than a satellite. It also has the ability to persist in a fixed vicinity overhead, whereas a satellite might only pass over a given spot once or twice per day.”

The construction of the Zephyr is minimalist. At first glance, it seems the craft consists of little more than a tail rudder and two electric motors attached to a 72-foot wing. Constructed of composite carbon fiber, the craft weighs a feather-light 120 pounds and has no wheels or landing gear — it is launched off of the shoulders and from the hands of five running individuals.

In past tests it has carried optical payloads and communications relays, and testers hope it will eventually be capable of an astonishing three months of uninterrupted flight.

“I've never dealt with a craft this large that is this light,” Penny said. “Every component of the aircraft is cutting edge.”

Virtually every square inch of the wingspan is covered by lightweight solar cells that charge batteries that power the motors. Also onboard are sophisticated electronics that allow the craft to be monitored and steered from a ground control station. The pilot, navigator and flight engineer who man this station are halfway through their mission of continuously monitoring the aircraft.

“The pilot is there to take over in the event of the flight control not working,” said King. “We intend to turn on the flight control early the first morning and leave it on for the rest of the flight, so hopefully the pilot's job will be very routine.”

Maiden flight

It is still dark as launch time approaches. The Zephyr is wheeled out of the hangar and pushed a quarter of a mile down an adjacent runway by five men accompanied by a small entourage of pickup trucks providing light.

Once in position, the craft is lifted off its dolly and placed atop five lightweight trestles carefully spaced along its wingspan. While the NAA observer and perhaps a dozen other spectators watch from a safe distance behind the craft, one of the men calculates the craft's exact position on the runway, then uses a long blue ribbon to check wind speed and direction.

Aerial testers favor the calm winds of typical YPG early mornings but are leery of launching the craft in the near absolute stillness present at this moment. Like their colleagues monitoring the weather from within the ground control station, King and his co-workers are also concerned by thick, low-hanging clouds over the runway.

YPG's meteorology team has already sent up two weather balloons and are confident that a slight breeze will pick up after sunrise, and that the fast-moving clouds will dissipate shortly thereafter. After a brief radio conference, the testers decide to wait.

As the sun slowly rises above Castle Dome, the crew waits anxiously, occasionally making adjustments to the covers over the craft's solar panels as they pace around. More than an hour after sunrise, the testers make the decision to launch the Zephyr.

Mission control turns on the electric motors as King and the four testers loft the craft onto their shoulders and begin jogging down the runway. They release the craft at 6:41 a.m. — it hangs precariously in midair as the men stop, then begins to ascend. There are breathless smiles and backslaps among the launchers and whoops from the spectators as the craft continues to rise toward the morning sun.

“It was brilliant,” King said. “We had a bit of a wait, but our patience paid off.”