A second mission, which rescued another four boys, commenced on Monday, July 9.
Tuesday, he tweeted from Thailand that he had been in the caves and that a mini-sub made from rocket parts and named "Wild Boar" after the boys' soccer team, was ready if needed and would be left in Thailand in case it could be of future use. "We hope it would be faster or same amount of time today".
The operation on Monday went more smoothly than on Sunday and took two hours less as the practice became more refined, he said. It is now unclear whether Musk or his technology will be used in the rescue efforts, but Musk confirmed via tweet that the submarine is in Thailand and ready to be used if needed. It could take Thai rescuers about four days to rescue all of the remaining team members.
"I've told them once this has died down let's really sit down and have a more in-depth interview on what's really happening", he said. "And it is up to the environment". "But if the rain god doesn't help, then it could be challenging". The same divers were deployed Monday because they were familiar the cave, authorities said. "We should learn from this experience to prevent it from happening again".
All 13 members of the Thai youth soccer team, 12 boys, ages 11-16, and their 25-year-old coach, have been successfully rescued from the flooded cave in northern Thailand. He said a medic and three SEALS in the cave, who've been looking after those trapped, will also come out.
All eight boys rescued on the first two days are being treated in an isolation ward in a Chiang Rai hospital.
Officials lavished praise on the Thai and global divers who executed the risky rescue mission, guiding boys who can barely swim and have no diving experience through a treacherous 4-kilometer-long (2 1/2-mile) escape route that twisted and turned and rose and fell inside the mountain cave complex.
The submarine weighs about 90 pounds dry and holds four oxygen tanks.
"The rescue has been huge", said volunteer helper Somjit Saenset, 56.
"I am not sure about children and how they will react".
The rest that were rescued on Tuesday are expected to join them.
Officials said all eight of the boys were healthy, though two of the four brought out Monday did have swollen lungs.
Somboon Sompiangjai, a father of one of the boys trapped in the cave, said divers are helping the strongest children first.
"(They) will be extracted today", rescue chief Narongsak Osottanakorn told reporters, adding the journey out should be faster than on previous days.
The boys underwent X-rays and blood tests and two who had signs of pneumonia were given antibiotics and are in a "normal state", he said, adding they will all remain under observation in hospital for a week.