CAMP PENDLETON, California — Maj. David Palka had seen combat in Iraq and Afghanistan, but roughly 90% of the Marines under his command, tasked with setting up a remote fire base in northern Iraq in 2016, had only heard the stories.

Their trial by fire in March 2016 came just hours after they landed on Army CH-47 helicopters under cover of darkness in Makhmur, Iraq. Getting off the helicopters at around 2 a.m., the Marines were in what was essentially open farmland with a large protective berm of dirt around their small perimeter.

"By 0900, we received the first rocket attack," Palka told Business Insider.

As a captain, Palka had led the Marines of Echo Battery, 2nd Battalion, 10th Marine Regiment when it was attached to the 26th Marine Expeditionary Unit from October 2015 to June 2016.

On Monday, Palka was awarded the Bronze Star medal (with combat V), the fourth-highest combat award, for what his battalion commander called "sustained valorous leadership." He'll also later this week receive the Leftwich Trophy, presented annually to a Marine company or battery commander who displays outstanding leadership.

Palka and his unit's foray into Iraq to set up an artillery support base had was shrouded in secrecy. But new details have emerged from that mission, showing that they were under constant threat and directly attacked more than a dozen times during their two and a half months there, according to interviews and documents reviewed by Business Insider.

"When they got the call, they were ready," Lt. Col. Jim Lively, the commander of Battalion Landing Team, 2nd Battalion, 6th Marines, and Palka's battalion commander at the time, told Business Insider.

'It was no surprise that we were rocketed'

When Palka and others in his advance party left their helicopter on March 12, they marked the first American boots on the ground in Iraq to set up a quasi-permanent base since US forces left in 2014.

At what would be named Fire Base Bell — in honor of Staff Sgt. Vincent Bell, a Marine who died in Afghanistan in 2011 — Palka and his Marines began to establish security and build bunkers to protect from enemy fire.

The base was initially protected by 60 infantry Marines from Echo Company 2/6 armed with rifles, machine guns, and mortars, along with an Army unit providing radar equipment that would detect and zero in on rockets fired from ISIS positions. Field artillery Marines brought four M777A2 Howitzers to the base just days later.

The base was small and had no creature comforts, and troops dug holes where they would man their guns, fight, and sleep.

"It was austere. There was the constant threat 24/7," Palka said. "My other deployments, you'd come back to a [forward operating base]. Or we'd remain on a FOB and shoot fire support in support of maneuver. We didn't have an adjacent unit to our left and our right. We were the only general-purpose ground force forward. There was no wire."

The Pentagon tried to keep the presence of Marines in Iraq quiet, but those efforts were thwarted one week after Palka arrived.

On March 19, Bell was hit once again by rockets fired from ISIS positions about 15 miles away.

"It was no surprise that we were rocketed," Palka said, noting that military planners had determined that Russian-made 122mm Katyusha rockets were the weapon of choice for ISIS at the time.

"I had received indirect fire on previous deployments, but nothing that large," he said.

The first rocket impact that day was a direct hit on the first gun position on the line.

"As soon as it impacted, it was obvious there were casualties," he said.

Staff Sgt. Louis Cardin, 27, was killed, and eight other Marines on Gun One were wounded. Immediately, the other Marines ran toward the rocketed position to give medical care, despite a second rocket landing a few hundred meters away.

"It was amazing to see them," Palka said. "The manifestation of all of our training coming to fruition."

Meanwhile, the Army counter-battery radar site homed in on where the rockets came from. And Palka, according to a military document summarizing his performance, calmly assessed casualties, called for medical evacuations, and executed an artillery counterfire mission of seven rounds back at ISIS's firing point. The document said the enemy's rocket position was "effectively" suppressed.

"Dave kept the team focused while they did the evacuation of casualties," Lively said. "They ran the counter-battery mission as the fire base was attacked."

'This was as kinetic as anything that I had experienced before'

Echo Battery's mission in Iraq was to set up a small outpost that could provide indirect fire support to Iraqi troops on the front lines. Field artillery Marines kept busy doing just that. Over slightly more than 60 days at the site, the unit fired more than 2,000 rounds, including high-explosive, illumination, and smoke.

Those efforts made it a big target, as ISIS shot more than 34 rounds at its position during that time. All told, the unit was attacked on 13 occasions, which included rockets, small arms, and suicide attacks.

"This was as kinetic as anything that I had experienced before," Palka said.

On two occasions, the base was attacked in a coordinated fashion by about a dozen or so ISIS fighters armed with explosive vests, small arms, machine guns, and grenades.

The first, which came just two days after Cardin's death, began with an ISIS fighter detonating his vest against an obstacle of concertina wire.

The Marines fought back over three hours on the night of March 21, eventually killing all the ISIS fighters with no American casualties. The artillery Marines, just over 2,000 feet from the enemy positions, fired illumination rounds as the grunts on the perimeter engaged with their rifles and machine guns.

"I'd say that ISIS and the enemy that we encountered in Iraq this past time ... they were more bold — the fact that they would infiltrate the forward line of troops and attempt to engage a Marine element with foreign fighters," Palka said. "Their weaponry and their tactics were more advanced. They were more well-trained than any other force that my Marines had directly engaged on previous deployments."

While Echo Battery fired its guns almost daily, it expended much of its ammunition in support of Iraqi forces gearing up for the assault later that year on ISIS in Mosul, Iraq's second-largest city. Ahead of the October offensive, the unit fired off more than 1,300 rounds in support of Iraqi troops attempting to take back villages on the outskirts of the city.

"Our mission was to provide force protection fire support to Iraqi security forces, which we did," Palka said.

Besides being the first back in Iraq, the unit had several other firsts, including the Corps' first combat use of precision-guided fuses, which make artillery rounds hit with pinpoint accuracy, and the successful employment of the Army's TPQ-53 radar system alongside Marines, which helped it quickly identify where rockets were coming from so they could be taken out.

"There's nothing I can put into words about how I feel about the Marines in that unit," Palka said. "Words don't do it justice. There's something that you feel and sense when you walk into a room with them."