– An 18-day mission to save 12 boys and a soccer coach trapped in a Thai cave succeeded without Elon Musk's mini-submersible, which was deemed unsuitable and left behind in the Tham Luang cave complex. It's "a reminder that sometimes this tech superhero doesn't quite match up to the Iron Man of his fans' dreams," says the BBC's Rory Cellan-Jones. Musk begs to differ. After rescue head Narongsak Osottanakorn said Musk's kid-sized sub built from rocket parts was "not practical for our mission," the billionaire SpaceX founder took to Twitter to question Osottanakorn's expertise. He "is not the subject matter expert," Musk tweeted Tuesday, sharing a July 7 email from a rescue diver, per the New York Times. It asks Musk to "please keep working on the capsule details." A spokesman for the diver said Tuesday that cave passages were too narrow for the sub, but "based on extensive cave video review & discussion with several divers who know journey, SpaceX engineering is absolutely certain that mini-sub can do entire journey & demonstrate at any time," Musk continued, adding he left the sub behind "in case it may be useful in the future." Aaron Mak at Slate gives him some credit. "Musk's involvement, though ultimately unnecessary, appears to have been well-intended and did not impede the operation," he writes. You can't fault a guy for trying, adds Bryan Clark at The Next Web. "Musk delivered a working submersible in around 30 hours in an attempt to solve a very real problem, a problem that undoubtedly costs hundreds of thousands of his own money in materials, research, and man hours," he says, deeming the effort "worthy of praise."