Search and rescue teams have now covered 7,600 square miles -- an area bigger than the state of Connecticut -- as they scour the ocean for the missing submersible, Coast Guard officials said.

A grid depicting the expanding search area is expected Tuesday night, according to a public information affairs lieutenant for the First District of the U.S. Coast Guard.

-ABC News' Miles Cohen

NASA released a statement Tuesday on the Titan, saying it remains "hopeful the crew will be found unharmed."

"NASA’s Marshall Space Flight Center had a Space Act Agreement with OceanGate, and consulted on materials and manufacturing processes for the submersible. NASA did not conduct testing and manufacturing via its workforce or facilities," the agency said.

-ABC News' Gina Sunseri

The U.S. Navy said it's sending to the search site experts and equipment "designed to provide reliable deep ocean lifting capacity for the recovery of large, bulky, and heavy undersea objects."

The equipment, which can lift up to 60,000 pounds, and the experts will arrive in Canada Tuesday night, the Navy said.

National Security Council spokesperson John Kirby said earlier Tuesday that the Navy was"on standby" to help with the search for the missing submersible, because the Navy has "some deep-water capabilities that the Coast Guard wouldn’t necessarily have."

President Joe Biden is "watching events closely," Kirby said, adding that Biden and the White House offer their thoughts "to the crew onboard, as well as to the -- what is no doubt -- worried family members back on shore."

Three U.S. Air Force C-17 cargo aircraft will be transporting commercial equipment from Buffalo, New York, to Newfoundland, Canada, to help with the search efforts, according to a U.S. official.

-ABC News' Luis Martinez

Rescuers racing against the clock to save the five people trapped in a tourist submersible nearly two miles deep in the Atlantic Ocean are facing major obstacles that could make saving the people onboard extremely difficult, according to a former U.S. Navy submarine commander.

Retired Capt. David Marquet told ABC News on Monday that this type of rescue operation is complicated because there aren’t nearby U.S. or Canadian underwater vessels that can go as deep as the Titanic wreckage, which sits 13,400 feet below the ocean’s surface. Also, the ocean is pitch black at that depth.

"The odds are against them," Marquet said. "There's a ship in Boston that has this ability to either lower cable and connect to it or have a claw. It's still a thousand miles away."

Even if a vessel was able to locate the submersible and lower a cable, it’s extremely difficult to safely navigate the waters and attach it, according to Marquet.

"You've got to get it exactly right," he told ABC News. "It's sort of like ... getting one of those toys out of those arcade machines. In general, you miss."

Rescuers do have one advantage, Marquet said, as weather conditions off the coast of Newfoundland are not rough and will not disturb any boat or vessel there.

Marquet added that if the five people aboard are still alive, they would be asked to sleep to conserve their oxygen.

"We would put the vast majority of the crew to sleep because that's when you're using the least amount of oxygen and you're expelling the least amount of carbon dioxide," he said.

-ABC News' Sam Sweeney and Ivan Pereira