"Could Use In Future": Elon Musk Defends His Submarine After Thai Rescue

Elon Musk's efforts to aid in the rescue of 13 people trapped in a Thai cave were ultimately unneeded, but the billionaire is confident his "kid-size submarine" could be used at some point in the future.

The remaining boys and their soccer coach were saved from the Tham Luang Cave by divers and volunteers on Tuesday. Chiang Rai Governor Narongsak Osotthanakorn, one of the leaders of the rescue mission, said Musk's equipment was "technologically sophisticated" but "not practical," according to the BBC. "It doesn't fit with our mission to go in the cave," Osotthanakorn said.

Musk took umbrage at the comment and defended the project on Twitter. He said engineers from his rocket company, Space Exploration Technologies Corp., who built the submarine, said they were "absolutely certain" the underwater vehicle could complete the entire journey after discussions with divers and "extensive cave video review." Musk posted an image of an email exchange with Richard Stanton, a British diver on site, who encouraged him to keep developing the capsule. Musk also disputed the BBC's characterization of Osotthanakorn as a "rescue chief."

Musk, working with teams from SpaceX, toiled through the weekend at the company's headquarters in Hawthorne, California, to design, build and test an aluminum rescue pod - continuing the effort well after the first set of boys were rescued on the other side of the world. The pod measures approximately 66 inches by 16 inches. The leak-proof pod sported a nose cone on its front to guard against the impact of rocks and can withstand water pressure from the flooded cave system, Musk said.

Videos of tests conducted in the swimming pool of Palisades Charter High School, about 20 miles from SpaceX headquarters, showed divers towing the pod through the water, lifting it out and depressurizing it. An engineer who had been riding inside then emerged from the tight space. He appeared to have just enough room to fit while lying down with his arms folded over his chest.

The aluminum pod followed earlier rescue ideas Musk suggested, including using an inflatable tube or air sock, and another type of pod made from Kevlar. Musk tweeted on Monday that the pod was "ready if needed" and that he would leave it in Thailand "in case it may be useful in the future." With some modifications, the project could come in handy on a future rocket mission, Musk wrote. "This could also work as an escape pod in space."