“We’re doing an unmanned flight first, to prove a couple of technology things,” Barbera said.
The launch is tentatively scheduled for 10 a.m. “Maybe earlier, depending on the weather,” Barbera said.
“We need winds that are blowing away from Portland and Seattle, to the northeast,” he said at his home in a wooded area north of Battle Ground.
The team has plotted out a climb rate of about a meter a second. It’s a slow, steady ascent — not the trajectory of a rocket launch — although they need enough lift to ensure that the craft will actually leave his own property.
“Nothing is more important than getting past the first tree,” Barbera said.
About half the payload will consist of ballast: a mixture of water and antifreeze. At their target altitude of 11,000 feet, the temperature is below freezing, explained team member James Sutherland.
There also will be some onboard computer technology to control the balloon cluster’s altitude. Some valves will release ballast, allowing the aircraft to climb; other valves will release helium, decreasing its altitude.
Other technology will transmit flight information such as direction, altitude and air temperature.
“Ideally, it will go to an altitude of 11,000 feet and hold that altitude for an hour,” Barbera said. “Then we want it to descend, hold that altitude for an hour, and then descend gently.”
While they’re not the first team to launch an unmanned balloon cluster, “as far as we know, nobody has done it with computer control,” Sutherland said.
They figure the unmanned craft will stay aloft for four or five hours.
If the GPS tracking system works and the team can monitor the balloon cluster’s flight on the Internet, “we should know exactly where it is,” Barbera said.
If things go according to plan, they will keep tabs on the flight for a couple of hours or so, then hit the road for an anticipated recovery on the other side of the Cascades.
“We expect it to land somewhere around Yakima,” Barbera said
Sunday’s unmanned test also will provide an opportunity to rehearse the hands-on chores of the manned balloon launch.
“A big part of the first flight’s objectives is practicing on three balloons: who grabs what, how we release them,” he said.
The public is welcome to watch Sunday’s launch, Barbera said. He lives just west of the Fargher Lake Store, just off state Highway 503.
“We will have parking signs, and we will be updating our Facebook page,” he said.
Tom Vogt: 360-735-4558; http://twitter.com/col_history; firstname.lastname@example.org.