Inside the secure perimeter at Beale Air Force Base is a heavily fenced area ringed by thick coils of barbed wire.
Behind the wire sits a large concrete pad with four dark, container-like structures, each decorated with military insignia. The containers sprout an assortment of huge tubes and wires.
They contain the brains for America's reconnaissance drones, known as Global Hawks. These drones, unlike the more famous Reaper and Predator drones, are not armed, though they provide crucial information in war.
On many days, one of the containers serves as a sort of latter-day cockpit for Dan, a pilot and mission commander with the 12th Reconnaissance Squadron at Beale, where he oversees four pilots. (At the request of the Air Force, The Bee agreed not to photograph the containers and to use pilots' first names only because of the classified nature of their work.)
The drones Dan pilots by remote control are sophisticated machines -- and costly, at roughly $217 million each. Despite its unarmed status, the drone's fuselage offers a threatening profile that looks part bird, part whale. It can fly at 50,000 feet and above and has been known to hover over a location for more than 20 hours.
Beale's drones fly about 12 missions each month and share reconnaissance work with a fleet of manned U-2 airplanes, also based at Beale. The U-2 became infamous in 1960 when CIA pilot Francis Gary Powers was shot down in one during a secret mission over what was then the Soviet Union. The incident became a huge embarrassment for the United States.
No such dangers face Dan as he pilots a Global Hawk. Most flying days, the biggest danger he faces is driving to the base from his home in Penn Valley. On most non-flying days he reports to work at 8 a.m. and is done by 5 p.m.
Once a pilot of KC-135 airplanes -- the Air Force's massive fuel tankers -- Dan still dons a flight suit and a bomber jacket to fly the drone in the container. "In the last 10 days, I've flown on all sides of the globe," he said.
In this new remote world, Dan's joystick has been replaced by a computer mouse. His cockpit view is now a tight array of four flat screens.
The right stuff for this kind of flying is not the cockiness of Chuck Yeager or the constitution to survive multiple G-forces. The prized talent here is multitasking.
"The most difficult part is sorting through all of the information that comes in," said Dan, a captain. "Sometimes we have to bring in another pilot just to handle all of it."
Two pilots work together in a container, which pilots refer to as a "shelter." It's a cramped environment about half the size of a subway car. The blare of air conditioning venting inside is deafening -- the trailers are kept at 60 degrees to protect the computers.
Typically, shifts last four hours, often more. "Some missions are so long you may be part of a team flying a mission that did a great thing, but you were not actually in the shelter when it happened," Dan said.
On Dan's flight suit is a patch that reads "Know Your Enemy." Dan's enemy is what is gleaned on a video display.
"We get intelligence briefings, and we build a huge situational awareness," said Dan. "But I don't consider that as qualifying me as knowing my enemy. I don't think I ever will."
The drones don't seem to inspire the same connection between pilot and machine as do manned aircraft. The U-2, for example, is affectionately called the "Dragon Lady." A similar moniker was not readily evident between pilot and drone at Beale.
Also gone is the thrill of flying. "The butterflies that you get in your stomach from flying? Yeah, I miss that," Dan said.
Often, piloting a Global Hawk is a game of hurry-up-and-wait. Getting one airborne is a complex affair. One day last week, Dan was charged with getting a Global Hawk airborne by 4 p.m. Glitches with software and satellite uplinks kept the drone stranded on the tarmac for hours. Eventually, it had to be refueled.
Global Hawk pilots bristle at being bunched in with armed drones like the Reaper and Predator, which have created ill will abroad due to strikes in Afghanistan, Yemen and Pakistan.
"The Global Hawk has been used in disaster relief and for partnership building," said Tim, a lieutenant colonel who is director of operations for the 12th Reconnaissance Squadron.
No other mission revealed the Global Hawk's potential for nonmilitary use more than Operation Tomodachi, in which the Global Hawk was charged with flying over one of the ruined reactors at Fukushima, Japan, after the massive tsunami struck in 2011.
"We got the call, and we spent 21 hours overhead," said Tim. "We conducted 18 sorties, 16 of them effective ... and we were the first to operate in a nuclear, biochemical environment."
There are now around 115 Global Hawk pilots worldwide, from a base in Guam to one in Sigonella, Italy, with every flight tracked at Beale.
And there is now a new kind of Global Hawk pilot on the scene: drone only.
"One of the guys I'm in charge of has only flown UAVs," said Dan, using the shorthand for unmanned aerial vehicle. "He's one of two that became the first that went through the UAV-only training."
Tim said there is no competitive nature or caste-system divide between aircraft-experienced pilots and those with no physical flight hours.
If anything, Tim said, the drone-only pilots seem to be prized as better multitaskers.
"The job they do is seamless ... and, no, neither of them played video games all that much."