Billionaire Elon Musk proposed a high-tech rescue of 12 boys and their soccer coach trapped in a flooded cave in Thailand, using a “tiny, kid-size submarine” made from part of one of his space company’s orbital rockets.

The chief executive of Tesla Inc. and Space Exploration Technologies Corp. made the suggestion on Saturday in a Twitter message, saying he’d received “great feedback from Thailand” as members of his engineering team descend on the scene that has galvanized the attention of people in Thailand and around the world.

“Construction complete in about 8 hours, then 17 hour flight to Thailand,” he said in one of a series of Twitter messages. That timeline would get the mini-sub to Thailand early Monday local time.

Got more great feedback from Thailand. Primary path is basically a tiny, kid-size submarine using the liquid oxygen transfer tube of Falcon rocket as hull. Light enough to be carried by 2 divers, small enough to get through narrow gaps. Extremely robust.

— Elon Musk (@elonmusk) July 7, 2018

Continue to be amazed by the bravery, resilience & tenacity of kids & diving team in Thailand. Human character at its best.

— Elon Musk (@elonmusk) July 7, 2018

The boys and their coach have been trapped in the cave system in the country’s north for about two weeks, and heavy rainfall looms in the days ahead. Rescuers are moving feverishly to lower water levels with pumps and prepare the boys, most of whom can’t swim, for a perilous, hours-long extraction that would include diving through pitch-black water with scuba gear.

Musk, who studied physics, has floated a number of ideas on Twitter on how to bring the stranded team to safety.

On Saturday, he suggested a rescue employing “a tiny, kid-size submarine using the liquid oxygen transfer tube of Falcon rocket as hull. Light enough to be carried by 2 divers, small enough to get through narrow gaps. Extremely robust.”

There was no immediate comment about the plan from Thai officials.

“Continue to be amazed by the bravery, resilience & tenacity of kids & diving team in Thailand,” Musk said in another tweet. “Human character at its best.”

Musk previously proposed using a double-layer Kevlar pressure pod or a long inflatable air sock to penetrate the narrow passageways and provide a rescue conduit. The tubes and pods are being built in the U.S., a spokesman said. Some equipment is traveling with his engineering the team and some will be express shipped.

Diving Risk

“No need for SCUBA mouthpiece or regulator,” Musk wrote about his suggested pods. “Training unnecessary & less susceptible to panic attack.” Musk said they were being tested Friday afternoon in a pool with a subject who had never been scuba diving.

Any air sock or tube would have to be tough enough to withstand high water pressure — potentially two tons of force at a depth of 15 feet– and sharp rocks, said Douglas Hart, a professor of mechanical engineering at the Massachusetts Institute of Technology.

Earlier Saturday, Musk tweeted there’s “some good feedback from cave experts in Thailand” and that he’s “iterating with them on an escape pod design that might be safe enough to try.”

“Also building an inflatable tube with airlocks,” he wrote. “Less likely to work, given tricky contours, but great if it does.”

SEAL Dies

A Thai Navy SEAL helping with the rescue operation died Friday after running out of oxygen, underlining the dangers of navigating the flooded cave system even for those with experience. Cave diving is widely regarded as treacherous and the stranded group is thought to have little swimming ability, let alone diving know-how.

Officials have also contemplated supplying the boys and their coach with food, water and oxygen to stay in the cave potentially for months until the monsoon ends and waters recede. But the expected heavy rains raise the risk of increased flooding and restricted access.

A spokesman for Musk has previously said that the billionaire’s companies may assist by trying to pinpoint the boys’ precise location using SpaceX or Boring Co. technology, pumping water or providing heavy-duty battery packs known as Tesla Inc. Powerwalls.