CLEARFIELD -- Families of ATK rocket engineers get to watch test motors fired at Promontory, but half a mile away is as close as they get.
So ATK Space Systems got NASA approval to let employees bring their families for some hands-on fun Saturday at the company's engineering development lab in the Freeport Center.
They got to see and touch the real thing, or at least as real as the lab test equipment and full-scale mock-ups can make it.
Plenty at the lab is real. ATK engineers could launch a mission at Kennedy Space Center from Clearfield if they had to.
On top of that, ATK had a real astronaut on hand.
Which was good. One of the first through the doors was Fred Brasfield. The vice president of ATK's next-generation booster program brought his grandchildren, Ivy, 2, and Addie, 5.
"They came to meet an astronaut," Brasfield said.
"I'm going to be one," Ivy said.
"Me, too," said Addie.
And meet an astronaut they did. On the premises was Charlie Precourt, a four-time shuttle astronaut who is ATK's vice president for advanced strategic programs.
The kids loved it, and it was that "this stuff is cool!" factor that ATK was trying to foster Saturday.
The lab is where ATK Space Systems develops the electronic, mechanical and computer controls that make its giant solid rocket motors work.
The space-shuttle era is over, so the lab is preparing the next generation of motors to power both ATK's commercial Liberty launch vehicle and NASA's newly announced Space Launch System.
Both Liberty and SLS will use booster motors similar to those that pushed the space shuttle, but the new ones are bigger and are used differently. The avionics are different, the way they attach to the loads they boost is different, and the loads themselves are different.
So ATK engineers have a lot of work to do. Nobody knows when the next real firing test will be, but it is several years away at least.
Paul Karner, program manager for avionics and controls, walked through the back of the lab where ATK has mock-ups of rocket components into which the engineers mount controls to make sure of even the most basic stuff like whether all of the parts fit together.
For example, ATK is working with the European space agency, Astrium, to build Liberty, a two-stage commercial rocket that is expected to take loads to the International Space Station.
So the lab has a three-story-tall segment representing the top of an ATK booster motor.
It has a giant cup-shaped structure on top. That is where the European-built second stage will sit.
There's a lot of plywood and duct tape inside, but the goal is to make sure wiring, parachutes, control modules and other equipment fit where they are supposed to.
"Several times, the computer designers say, 'This is good. This fits," and we put it together and it doesn't," Karner said.
The Liberty and SLS boosters use five solid rocket motor segments instead of the four that made up a space shuttle motor.
To control and fire each booster, engineers have to run wiring up the outside in a "system tunnel." That tunnel also has to hold the long, thin tube of explosive that blows up the rocket if something goes wrong.
Electric wires can generate a magnetic field, which could set off the explosive charge, "so you don't want them laying on the charge," Karner said. The mock-up allows engineers to safely design the arrangement of those cables and controls.
The engineers also test the software that runs the motors.
"What we try to do is break the flight system," intentionally introducing problems to see what other problems crop up. Engineers create lists of cascading problems that one fault can cause, then try to stop those problems from happening so the rocket system is as survivable as possible.
"What we really spend most of our time on is redundancy," Karner said. "We've got to be able to survive a failure. We've got to be able to take a hit and keep going."
This is the first time since the space shuttle that engineers are designing and building a new human-rated space system, he said.
Because most of his engineers were younger than 10 years old when the space shuttle was designed, Karner tries to stress to them that what they are doing is historic.
"I remind them every morning, 'You realize you're leaving your thumbprint on history?' "
They seem to know it.
Engineer Mike Dickemore was showing his wife, Maya, his cubicle. It has the usual computers and neatly arranged books and papers, as well as pictures of ATK rockets and other NASA hardware.
On a cabinet is a line drawing of the internal structures of an Ares IX rocket, the first test rocket for the now-discontinued Ares system that was successfully launched in 2009.
Dickemore helped design the instruments, controls and data-collection systems of that rocket. He is now working to modify them for future uses.
"I was doing an average of 60 to 80 hours a week for over a year," he said, but didn't seem to mind.
"I've got a cool job, I really do. Not many people can say you work on a national treasure, but I really do.
"It's very cool, very cool work that we do here."