The hurricane-weakened Cold War radar station, called Texas Tower No. 4, collapsed during a fierce winter storm in January 1961.
The station stood about 80 miles southeast of New York City, one of three similar stations built off the East Coast. The fixed ocean platforms supported the long-range radar antennas normally used on land and extended early warning of a Soviet air attack by about 30 minutes.
But Texas Tower No. 4, nicknamed "Old Shaky," had stability problems from the start, partly because it was built in deeper waters than the other two stations. It also sustained heavy damage in a hurricane just months before it fell.
Obama called the collapse a "tragic event" in the letter dated Feb. 4 and addressed to the Texas Tower Association, an organization dedicated to remembering the collapse.
"For over two centuries, our Nation's sons and daughters have watched over her shores with unwavering patriotism and quiet courage," the president wrote. "As you reflect on the 28 airmen and civilians that lost their lives half a century ago in this tragic event, I hope you take pride in your efforts to remember their service and sacrifice."
He concludes, "Our Nation is grateful for the dedication, pride, and commitment of all those who risked their lives to ensure the safety of their fellow Americans."
Obama wrote the letter after a request from U.S. Sen. John Kerry, D-Mass., who was contacted years ago by Don Slutzky, a one-time civilian worker on Texas Tower No. 4 who has long advocated for presidential recognition for the victims.
Next week, Kerry's veteran liaisons will deliver the letter to Don Abbott of Malden, who is the son of victim David Abbott and head of the Texas Tower Association. Kerry's office said the liaisons will give Abbott letters from Kerry and copies of Obama's letter to deliver to the families of each Texas Tower No. 4 victim, as well as to the families of four people who died on the other towers.