In a parking lot four miles from the space shuttle Discovery launch pad, Hawai'i's Chris Davis watched with satisfaction as the shuttle rocketed into a clear blue Florida sky yesterday, confident the foam insulation his team had been testing was in good condition.

"I was confident we had done everything we can to reasonably assure that we wouldn't have any foam of large sizes (coming off)," said Davis, 50, reached by phone several hours after yesterday's successful launch. "Small pieces may come off and that's OK."

Davis is NASA's senior project manager at the Kennedy Space center, a 1973 graduate of Damien Memorial High and a graduate of the University of Hawai'i where he earned a degree in mechanical engineering in 1983. He admitted it was the best Fourth of July he could imagine.

Despite the distance — as close as allowable — the roar of the shuttle sounded like the full-throttle revving of a motorcycle engine that's capable of shaking windows and setting off car alarms.

"I've seen quite a few and they never cease to amaze me," Davis said of shuttle launches. "It's the largest fireworks in the world. I'd have to say better than Ala Moana Beach."

As NASA scrubbed Discovery's first two launch days because of weather, and then analyzed loss of a small piece of foam insulation, Davis waited to see if he would be needed.

"Any suspicions of there being further damage, there was a possibility I would assist them in that," he said. "The foam damage was very small compared to what it could tolerate so it wasn't an issue."

Davis would know. Since the 2003 Columbia disaster when a suitcase-sized piece of foam insulation broke free from the shuttle, setting up a disastrous reentry scenario that tore the spacecraft apart, took seven lives, and spread debris across Texas and Louisiana, one of his primary tasks has been to determine what size of foam debris is considered allowable.

"Now we know that the acceptable amount of foam that can be lost off the external tank is about 10 cubic inches — about the size of a hockey puck," he said.

His work in this area earned him the coveted Space Flight Awareness Award, a top honor in the space shuttle program.

Along with working on the foam insulation, his team uses X-ray, ultrasound and even infrared and laser measurement tools to inspect the shuttle surface for any corrosion or weakness.

After the launch, and with the knowledge that other small pieces had broken loose during launch, Davis said the astronauts would be doing several inspections.

"There might have been a piece that struck the orbiter but it seemed to be very inconsequential," he said. "When they dock at the space station it will have cameras and they'll also do an inspection with the robotic arm and a space walk."

Davis has been working on questions regarding the foam insulation for a decade, but more intensely since the 2003 accident. His team also works on ways to keep birds from striking the shuttle during launch.

"The most critical thing is not having a bird strike during ascent," he said. "It's not high risk, but we want to make sure we address this problem."

In averting bird strikes his team has investigated odors that would deter birds from coming into the area, analyzed scanning the area 200 to 500 feet above the launch site with radar, and is also considered using noise to scare them off.

So far the most promise has come from a noise generator that creates sound equal to a 120 decibel rock concert.

This is the second shuttle launch in two years since NASA has returned to space flight after the 2003 loss of Columbia.

Discovery's mission is to ferry critical supplies such as food and water to the space station, as well as deliver another person to the station crew.

The plan includes three space walks, as well as a full investigation of the shuttle surface for any potential damage from foam pieces that fell away during launch.

Davis said NASA engineers try to keep the foam insulation layer as thin as possible, because it's the thicker pieces that are more likely to come off. Those would be pieces thicker than three inches, he said.

Davis joined NASA in 1990 after working for the Navy, mainly on the P-3C surveillance aircraft. He received his Master's degree in mechanical engineering in 1993 from the University of Central Florida.

Reach Beverly Creamer at bcreamer@honoluluadvertiser.com.