Debris from destroyed Space Shuttle Challenger found on ocean floor 36 years on

The ill-fated Challenger broke apart soon after liftoff in 1986. Now, a crew of divers has uncovered some more of its debris while searching for clues in another mystery.

Divers spotted the section of the shuttle while looking for wreckage of a WW II plane

In this undated photo provided by The History Channel, underwater explorer and marine biologist Mike Barnette and wreck diver Jimmy Gadomski explore a 20-foot segment of the Space Shuttle Challenger that was found off the coast of Florida. (The History Channel/The Associated Press)

A large section of the destroyed space shuttle Challenger has been found buried in sand at the bottom of the Atlantic, more than three decades after the tragedy that killed a schoolteacher and six others.

NASA's Kennedy Space Center announced the discovery Thursday.

"Of course, the emotions come back, right?" said Michael Ciannilli, a NASA manager who confirmed the remnant's authenticity.

When he saw the underwater video footage, "My heart skipped a beat, I must say, and it brought me right back to 1986 ... and what we all went through as a nation."

It's one of the biggest pieces of Challenger found in the decades since the accident, according to Ciannilli, and the first remnant to be discovered since two fragments from the left wing washed ashore in 1996.

Divers for a History Channel TV documentary first spotted the piece in March while looking for wreckage of a Second World War plane. NASA verified through video a few months ago that the piece was part of the shuttle that broke apart shortly after liftoff on Jan. 28, 1986.

All seven on board were killed, including the first schoolteacher bound for space, Christa McAuliffe.

The underwater video provided "pretty clear and convincing evidence," said Ciannilli.

The piece is more than 4.5 metres by 4.5 metres, and likely bigger because part of it is covered with sand. Because there are square thermal tiles on the piece, it's believed to be from the shuttle's belly, Ciannilli said.

Divers first spotted the piece of the Challenger in March while looking for wreckage of a Second World War plane for a new History Channel documentary. (The History Channel/The Associated Press)

Future of debris unclear

The fragment remains on the ocean floor just off the Florida coast near Cape Canaveral as NASA determines the next step. It remains the property of the U.S. government. The families of all seven Challenger crew members have been notified.

"We want to make sure whatever we do, we do the right thing for the legacy of the crew," Ciannilli said.

Roughly 107 metric tons of Challenger debris have been recovered since the accident. That represents about 47 per cent of the entire vehicle, including parts of the two solid-fuel boosters and external fuel tank.

The Space Shuttle Challenger lifts off from the Kennedy Space Center in Cape Canaveral, Fla., on Jan. 28, 1986. A short time later, the Challenger exploded, killing the crew of seven onboard. (Thom Baur/The Associated Press)

Most of the recovered wreckage remains buried in abandoned missile silos at Cape Canaveral Space Force Station. The exception is a left side shuttle panel on display at Kennedy Space Center's visitor complex, alongside the charred cockpit window frame from shuttle Columbia, which broke apart over Texas during re-entry in 2003, killing seven astronauts.

Far less has been recovered of Columbia — 38 metric tons representing 38 per cent of the shuttle. The Columbia remains are stored in converted offices inside Kennedy's massive hangar.

Launched on an exceptionally cold morning, Challenger was brought down by eroded O-ring seals in the right booster. Columbia ended up with a slashed left wing, the result of foam insulation breaking off the external fuel tank at liftoff. Mismanagement was also blamed.

A History Channel documentary detailing the latest Challenger discovery airs Nov. 22.