U.S. and Czech soldiers patrol north of Bagram Airfield on Oct. 20 looking for signs of Taliban fighters. (Photo by Dan Lamothe/ The Washington Post)

BAGRAM AIR BASE, Afghanistan — When Krissie K. Davis deployed to Afghanistan this past spring with the U.S. military, she was excited about her mission and told her family that she would be safe. A 54-year-old grandmother and civilian employee with the Defense Logistics Agency, she worked at sprawling Bagram air base preparing equipment for disposal as part of the base’s possible closure. She talked to her family almost every day from 7,500 miles away.

In an instant, however, that changed. While driving on base early June 8, Davis was hit by a Taliban rocket. Her remains arrived at Dover Air Force Base in Delaware within days, treated with the same solemnity and respect offered to active-duty service members killed in combat, said her daughter, Angela Langley Mitchell.

“I don’t think she really knew what she was getting into,” said Mitchell, of Lincoln, Ala. “She said she was never anywhere near where the missiles were being shot into.”

[Meet the guns protecting U.S. bases from rocket attacks in Afghanistan]

The death of Davis highlights the complicated nature of the Afghanistan war as its 15th year begins. While U.S. officials debate the merit of expanding the war against the Islamic State militant group in Iraq and Syria, Washington keeps three times as many service members in Afghanistan, with an even larger force of contractors and civilian employees assisting.

Combat operations in Afghanistan are over, White House and Pentagon officials say, but those deployed still face a variety of attacks in what commanders call “noncombat” operations — even, as with Davis, when driving to work at dawn on a base with a 13-mile perimeter.

“It’s obviously still a combat environment, even when we’re focusing on protecting” Bagram, said Army Lt. Col. Matt McCulley, who leads Task Force Buffalo, a unit devoted to providing security on and around the airfield. “If you don’t go out, you’ll never know something is wrong — until something catastrophic happens.”

Fifteen Americans have died and 63 have been wounded in Afghanistan since the beginning of the year, including five killed in action, according to statistics released by the Pentagon on Nov. 18. The United States will keep 9,800 service members there through most of 2016, with 5,500 expected to stay through at least 2017, following an October decision by Obama to extend how long he will keep thousands of troops deployed.

U.S. and Czech soldiers patrol north of Bagram Airfield in Afghanistan on Oct. 20. (Photo by Dan Lamothe/ The Washington Post)

In Iraq, meanwhile, the United States has about 3,300 troops deployed, with plans to send about 50 Special Forces soldiers to Syria in coming days to work with rebel groups fighting the Islamic State. Ten American service members involved in the operation have died since it began in June 2014, and five have been wounded in action. Of the 10 deaths, one — Master Sgt. Joshua L. Wheeler, a member of the Army’s elite Delta Force – was killed in action. Wheeler was buried at Arlington Cemetery Wednesday.

Obama’s decision to keep more troops in Afghanistan longer came as the country faces a spike in activity by the Taliban as well as the Islamic State and al-Qaeda.

Extending the U.S. mission in Afghanistan means that troops will continue to face improvised explosive devices and ambushes, even though the mission has turned almost entirely to advising and assisting.

[‘Probably the largest’ al-Qaeda training camp ever destroyed in Afghanistan]

Army Gen. John Campbell, the top U.S. commander in Afghanistan, said in an Oct. 30 interview in his office in Kabul that he has “no issue if our young soldiers say they’re in combat,” even though senior leaders stress that the U.S. role in Afghanistan is no longer a combat operation.

“I want them to do everything they can to protect themselves and the buddies they have with them, and if they’re prepared for combat and they have that mind-set, then they are good,” Campbell said. “But what the president said is we are not engaged in combat operations. We are doing train, advise and assist. . . . When you do train, advise and assist, and you are in a very hostile area, and you are that young kid on the ground, and you’ve got an IED going off or someone shoots you, your mind says you are in combat, and I’m okay with that. All right?”

But there is a difference between the offensive combat operations the United States led for years and the training mission now, Campbell said. He pulled a stack of cards, each laminated, with the name and information of each coalition service member who has been killed in Afghanistan since he became the commander there in August 2014. With the new mission, he said, the stack is much smaller than it used to be.

Krissie Davis, right, and her daughter Angela Langley Mitchell. (Photo courtesy the Davis family) Krissie Davis, right, and her daughter Angela Langley Mitchell. (Photo courtesy the Davis family)

Coalition troops and civilians working at Bagram have had several stark reminders of that this year. In Davis’s case, she was traveling from a cafeteria after eating breakfast to her job on base when the rocket struck, said Mitchell, her daughter. Davis worked at the Anniston Army Depot in Alabama while home and had previously deployed to Kyrgyzstan, where the United States maintained an airfield until 2014. She had not deployed to a war zone before.

“When she told me she was going to Afghanistan, I begged and pleaded with her not to go,” Mitchell said. “Even though they say combat is over, I just had a friend who came back from there, and I knew it was kind of dangerous.”

At Bagram, the coalition unit providing security around the base includes a combination of soldiers from the United States, the Czech Republic, the Republic of Georgia, and U.S. Marines who advise the Georgians. Different formations in Task Force Buffalo patrol various areas, facing ambushes and IEDs within a couple miles of the installation.

In one incident in October, for instance, U.S. Marines rolled over an improvised explosive device within a couple miles of the airfield, said the unit’s commander, Lt. Col. Brad Grosvenor. The Marines were in a mine-resistant vehicle, and all survived without major injuries, he said.

[How this elite Air Force rescue squadron’s mission has evolved in Afghanistan]

The U.S. military would likely want more forces to keep a large installation like Bagram safe, but have done so with the number of service members they have in part because of the ways technology has been incorporated into the effort. Ground penetrating radar is used to make sure enemy fighters don’t use tunnels to sneak up on the coalition, for example, said Army Maj. Gen. Jim Rainey, who rotated out as the top commander at Bagram recently.

In another example, U.S. soldiers flying Apache helicopters responded Oct. 14 after an Army route clearance unit with the 442nd Engineer Company from Houston was ambushed by insurgents wielding small arms northeast of Bagram, McCulley said. The pilots were able to track a live surveillance feed recorded from an Army MQ-1C Gray Eagle drone to track enemy fighters on the ground – a first for them in combat, said Capt. Harrison Carmody, an Apache pilot with the 101st Airborne Division of Fort Campbell, Ky.

“If we’re trying to follow a guy and he’s left the ring we can see him, it can follow them all the way to central Afghanistan,” Carmody said.

There are fundamental differences between the security operations around bases, such as Bagram, and combat operations, Rainey said. “It’s a nonnegotiable” that the military will protect anyone living at Bagram, he said, but there is coordination and agreements in place with the Afghan government that defines how it is done, he said. Afghan forces must be consulted if a ground operation exceeds an undisclosed perimeter outside the base.

“When you’re static on a place like Bagram airfield, we’re never going to sit here on this base and let the enemy shoot rockets and plant IEDs without going out and protecting ourselves,” said Rainey, of the 3rd Infantry Division at Fort Stewart, Ga. “We’re allowed to patrol outside of the perimeter fence line to protect our men and women here.”

Correction: An earlier version of this story misidentified the agency with which Krissie Davis deployed.