SACRAMENTO, Calif. -- Dripping sweat and coughing on dusty air, Joe Griffin prepares to make yet another trek up a rocky hillside. Over the course of a month, he will take this short hike hundreds of times. Luckily, the altitude of Laos's mountainous Xiangkhoang Province provides a small measure of relief from the heat and humidity. Each trip up the mountain concludes with Griffin sifting through buckets upon buckets of dirt and soil, searching for a clue -- any clue -- to find the remains of an American pilot who crashed nearly a half century ago.

The determined effort is one of 17 planned month-long expeditions the U.S. Army Corps of Engineers will support this year throughout Southeast Asia to recover remains of lost American military service members and civilians from the Vietnam War era.

"I couldn't pass up this opportunity," says Griffin, an archeologist for the Corps' Sacramento District. "The prospect of bringing closure to a family who's been wondering for decades about their loved ones feels really good."

Griffin will work 28 out of 30 days he spends in the jungle, leading an expeditionary team of 18 active military members and 50 local Hmong villagers in examining more than a quarter acre of dirt and soil to find what, at times, feels like a needle in a haystack.

This isn't the first search and recovery mission, nor will it be the last.

In total, 1,028 missing Americans have been accounted for in Laos, Vietnam, China and Cambodia; however, more than 1,600 military personnel and civilians remain missing.

The Defense POW/MIA Accounting Agency (DPAA), whose mission is to 'provide the fullest possible accounting for our missing personnel to their families and the nation,' leads the recovery efforts and assembles the team of excavators, explosive ordinance technicians, aircraft specialists, translators and a handful of other disciplines.

Varying levels of technical understanding, language barriers, and exhausting days make communication exceptionally challenging, but everyone is motivated by a common goal.

"We kept an information board to record our findings, but it also had a photograph and some details of the aviator," Griffin explains. "Understanding who this person was and seeing their face daily really personalizes the effort."

Serving as the sole archeological professional on a joint-service recovery team is a stark contrast from his day job, where he primarily serves as a legal compliance consultant on Corps civil works projects, but Griffin isn't new to conducting archeological field work.

Upon earning a graduate degree from California State University, Sacramento in 2013, Griffin found himself traveling to places like Peru and Egypt to assist research projects. And his archeological curiosity dates back even further.

When he was a teenager, Griffin discovered an old-fashioned manual water pump in his backyard. He took it to the local museum with the hopes that it would have some historical significance.

"I got very excited because I could tell it was old," says Griffin. "I felt its age might have given it some positive, intrinsic value."

While the results disappointed Griffin, that passion as well as his global experience and Corps expertise place Griffin among a select group of volunteers with the skill set DPAA needs to fulfill its mission.

Griffin's name comes up regularly when talking about the next generation of experts who are candidates to lead an expedition, says Dr. Michael "Sonny" Trimble, director for the Corps' Mandatory Center of Expertise for the Curation and Management of Archeological Collections.

The center has been sending archeologists on forensic investigations across the globe in support of agencies like DPAA since the early 1990's.

Jane Rinck, chief of the Cultural, Recreation, and Social Analysis Section for the Corps, says losing Griffin for the required training and month-long mission was well worth the value he's brought back home.

"It's a fantastic developmental opportunity for Joe that many archeologists may never get in their lifetime," says Rinck. "Not only do we get to benefit from his newly-acquired archeological experience, but also from him leading a multi-disciplinary team."

The experience provided Griffin with a deep, personal satisfaction that has him looking forward to leading another DPAA mission next year in Laos, Vietnam, or possibly even Cambodia.

Today, the field work Griffin began continues with another Corps archeologist taking over. It may be years before the forensics case is closed, but the team presses on and the mission remains the same -- to recover and repatriate a long lost but never forgotten American.

Author's Note: Portions of Griffin's interview were withheld due to the sensitive nature of the continued investigation. Successful recoveries, however, are publicly available for review on the DPAA Facebook page once service members are returned to the United States.