In the spring of 1965, within weeks of 3,500 American Marines arriving in Vietnam, a 39-year-old Briton named Larry Burrows began work on a feature for LIFE magazine, chronicling the day-to-day experience of U.S. troops on the ground – and in the air – in the midst of the rapidly widening war. The photographs in this gallery focus on a calamitous March 31, 1965, helicopter mission; Burrows’ “report from Da Nang”, featuring his pictures and his personal account of the harrowing operation, was published two weeks later as a now-famous cover story in the April 16, 1965, issue of LIFE.

Photo: Man your battle stations: The crew chief of helicopter Yankee Papa 13, lance corporal James C. Farley, mans an M-60 machine gun during a mission near Da Nang, Vietnam on March 31, 1965. (Photo by Larry Burrows/Time & Life Pictures)

“Lafayette Ronald Hubbard (March 13, 1911 – January 24, 1986), better known as L. Ron Hubbard (and often referred to by his initials, LRH), was an American pulp fiction author and religious leader who founded the Church of Scientology. After establishing a career as a writer, becoming best known for his science fiction and fantasy stories, he developed a self-help system called Dianetics which was first published in May 1950. He subsequently developed his ideas into a wide-ranging set of doctrines and rituals as part of a new religious movement that he called Scientology. His writings became the guiding texts for the Church of Scientology and a number of affiliated organizations that address such diverse topics as business administration, literacy and drug rehabilitation”. – Wikipedia

Photo: American science fiction writer L. Ron Hubbard, founder of the Church of Scientology, uses his Hubbard Electrometer (patent pending) to determine whether tomatoes experience pain, 1959. His work led him to the conclusion that tomatoes “scream when sliced”. (Photo by Scott Lauder/Evening Standard/Hulton Archive/Getty Images)

Residents, covered with mud and dried banana leaves, ask for money and candles from police before attending a mass celebrating the feast day of the Catholic patron Saint John the Baptist in the village of Bibiclat, Nueva Ecija, north of Manila, June 24, 2013. Hundreds of devotees took part in this annual religious tradition, which has been held in the village since 1945. (Photo by Cheryl Ravelo/Reuters)

Riot police scuffle with pro-democracy students after hundreds of protesters stormed into a restricted area at the government headquarters, after a rally ahead of the October 1 “Occupy Central” civil disobedience movement in Hong Kong September 27, 2014. Hong Kong riot police used pepper spray on Saturday to disperse dozens of students who had stormed government headquarters, but an equal number held their ground in protests against Beijing's tightening grip on the city. (Photo by Tyrone Siu/Reuters)

Mount Sinabung spews pyroclastic smoke, seen from Tiga Pancur village on October 13, 2014 in Berastagi, Karo district, North Sumatra, Indonesia. Mount Sinabung, which has lain dormant for over 400 years, has been intermittently erupting since September 15 last year, killing 15 people and forcing hundreds to flee their homes. According to The National Disaster Mitigation Agency, more than 3,000 residents are still displaced. (Photo by Ulet Ifansasti/Getty Images)

In a 200-acre-plus dump 5 kilometers north of Haiti’s capital, Port-au-Prince, hundreds of men, women and children scavenge day and night through the burning wasteland. They earn $12 to $15 a day – on a good day – for recycling plastics as well as clothing, household items and aluminum (for smelting). Some 5,000 tons of waste is created each day in the Port-au-Prince area. (Photo and caption by Giles Clarke/Getty Images Reportage)

Two styles of cleaned bird's nest, Yan Zhan (L) and Su Zhan (R) await repacking at a processing plant in Kuala Lumpur, February 17, 2015. Prized in China for is alleged health benefits for hundreds of years, nests made from swiftlets' saliva are being mixed into coffee and cereal as the Southeast Asian producers of the delicacy seek to broaden its appeal, and their profit margins. The nests are among the world's most expensive foods, selling for up to $2,500 a kg and the swiftlets that weave them are indigenous to Indonesia, Malaysia, Thailand and Vietnam. (Photo by Olivia Harris/Reuters)

A police officer walks along a street of the burning village of Smolenka near Chita on Monday, April 13, 2015. Russian authorities say out-of-control agricultural fires have killed at least 15 people, injured hundreds more and destroyed or damaged more than 1,000 homes in Siberia. The fires were started by farmers burning the grass in their fields, but spread quickly because of strong winds. (Photo by Evgeny Yepanchintsev/AP Photo)