Elon Musk says his newly made submarine could have worked in the recent rescue mission in Thailand, and he may even deploy it underwater again or in space.

On Tuesday, Musk — who runs Tesla, SpaceX, and the Boring Company, among other things — took to Twitter to dispute a claim from a Thai official that the mini-submarine built by SpaceX and Boring Company engineers was impractical for the rescue of several Thai boys from a flooded cave, even though the same official praised the invention.

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And though divers rescued the boys and the capsule was not needed, Musk also said he was confident it could make the entire journey through the cave, based on video footage and talks with the divers.

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He said the pod could be used for other types of rescues, such as for "vulnerable patients" in toxic environments.

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Musk showed engineers testing the capsule in a pool in Los Angeles over the weekend.

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What follows is a basic description of the sub based on several tweets Musk has sent over the last several days.

The sub is fitted for a child or small adult, Musk said in a tweet. It is made from a liquid oxygen transfer tube that comes from one of SpaceX's Falcon 9 rockets. The team had previously considered making the sub from kevlar and made an inflatable vessel as a backup.

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They chose the oxygen tube, which is made of aluminum and with a diameter of 31 centimeters, because it would be small enough to fit through the tight caves and light enough to be carried by rescue divers. It has compartments for rocks or dive weights to adjust its buoyancy. Aluminum has high thermal conductivity, so the inside temperature of the capsule would be similar to the outside temperature. If that wasn't desired, Musk said, the capsule could be lined with a neoprene sleeve for insulation.

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The device has eight handles, four on its front and another four on its rear. It also has four connections for air tanks spread around the sub. Each of those connectors is recessed and fitted with a secondary cap to prevent leaking if the connectors are struck by something outside the sub.

And here are some pictures of the tubes as they were being built and tested.

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