With her family close by, 5-year-old Brooke Bankoske gazed intently at one of the computer monitors in the command post of the 7th Space Warning Squadron at Beale Air Force Base, hoping to see Santa Claus fly across the sky somewhere around the globe.
"How do you think we track Santa?" said Lt. Jake Slagle, crew commander.
"On the TV," replied Brooke.
On an ordinary day, the squadron's mission is to keep an eye on the skies from Alaska to Mexico, watching for hostile missile launches, preparing to help intercept those missiles and tracking some 3,000 satellites as they pass overhead in the heavens.
But on Christmas Eve, the focus changes to include the tracking of Santa Claus in conjunction with NORAD, the military organization responsible for the air and sea defense of North America.
It's a serious duty, one that Saturday involved eight tour groups with a total of 216 children and family members who'd been primed with hot chocolate and cookies.
They were prepared to ask the tough questions.
"Have you been naughty, or have you been nice?" demanded Brooke.
The adults chuckled. The children looked momentarily perplexed, until a NORAD video of Santa swooping over the Taj Mahal played on one of the screens.
"Where's NORAD?" asked Eddie Mendez, 7.
"It's in Colorado in the mountains," said Slagle.
In what long ago became an annual tradition, Colorado Springs-based NORAD, or the North American Aerospace Defense Command, has been tracking Santa Claus each Christmas since 1955, with teams of volunteers fielding thousands of calls each year from children eager to know St. Nick's whereabouts.
The Bankoskes Jeff and Michelle, along with Brooke and her 1-year-old sister, Grace began the morning by watching online NORAD updates on Santa's progress.
"When I showed Brooke, she started to cry," said Michelle.
The 7th Space Warning Squadron's Christmas Eve tours, which primarily involve families associated with the base, began years ago, as well.
"People start asking about them on the base in September and October," said Lt. Col. Scott Schroff, who commands the squadron. "When we set up the sign-ups, all the slots were filled by the end of the day."
Perched on a windy hillside at Beale, near Marysville, the squadron's 10-story, three-sided building is tilted at a 20-degree angle and studded on two sides with phased array radar antenna elements.
All to monitor the skies. Or Santa Claus.
"Eddie was so excited about the tour that he didn't want to go to bed last night," said his sister, 15-year-old Annalyssa Mendez.
The siblings attended the tour with their parents, Eddie and Laura Mendez, their grandmother, Anita Chavez, and Annalyssa's friend, Emily Boothe.
"I was up late making a surprise for my mom and dad," Eddie said shyly. "It's a slide show, and the music is 'Feliz Navidad.' "
"And we made brownies, too," said his sister.
NORAD's Santa outreach this year involved social media components, including a smart phone app. Slagle carefully explained to the tour group the high-tech science behind the tracking of Santa.
"We track the cookie crumbs that Santa leaves in his sleigh," he said. "They have little nuclear isotopes on them, so now we have a lock on Santa Claus."