The mini-submarine created by SpaceX engineers may not play a role in the crisis it was designed for — the Thai cave rescue drama that’s now speeding to a resolution — but it could be a lifesaver for future space missions.
“With some mods, this could also work as an escape pod in space,” SpaceX’s billionaire CEO, Elon Musk, said today in a series of tweets sharing the team’s progress.
Last week, Musk’s Twitter followers asked him what he could do to help the team in Thailand that’s working to extract 12 young soccer players and their coach from a flooded cave.
After considering a “bouncy castle” air tube that the kids might be able to wriggle through to safety, Musk and his team settled on the idea of building a kid-sized submarine, equipped with external air tanks. A foot-wide liquid oxygen transfer tube, originally built for SpaceX’s Falcon 9 rocket, would serve as the hull.
The contraption went through dive-pool tests at Palisades Charter High School in Los Angeles and was sent on a 17-hour flight to Thailand.
Meanwhile, the rescue team at the Tham Luang cave complex decided that the situation was too dire to wait any longer. Over the weekend, a team of expert divers began escorting the kids out of the cave. At times, the boys had to be hooked up with full-face oxygen masks as they swam through water filling the narrow, pitch-black cave channels.
The crisis could be resolved without having to resort to SpaceX’s mini-sub, and without further fatalities, which everyone agrees would be good news.
But in today’s tweets, Musk made clear that he wouldn’t consider the effort wasted even if it doesn’t come into play in the flooded Thai cave. The concept could come in handy for future underwater rescues on Earth, or rescues in the vacuum of space.
In any case, it’s instructive to see how the crowdsourced engineering exercise unfolded over the course of just a couple of days. That’s why we’re passing along this long string of tweets documenting the creation and testing of the mini-sub:
Some good feedback from cave experts in Thailand. Iterating with them on an escape pod design that might be safe enough to try. Also building an inflatable tube with airlocks. Less likely to work, given tricky contours, but great if it does.
— Elon Musk (@elonmusk) July 7, 2018
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
Well, can you get it done in time before the rains flood the cave-?
— Aiyana Skye (@aiyanaskye) July 7, 2018
Construction complete in about 8 hours, then 17 hour flight to Thailand
— Elon Musk (@elonmusk) July 7, 2018
I’m in LA working with the SpaceX team building the kid mini-sub
— Elon Musk (@elonmusk) July 7, 2018
4 handles/hitch points on front & 4 on rear. 2 air tank connections on front & 2 on rear, allowing 1 to 4 tanks simultaneously connected, all recessed for impact protection w secondary cap seal if leak develops.
— Elon Musk (@elonmusk) July 7, 2018
Fitted for a kid or small adult to minimize open air. Segmented compartments to place rocks or dive weights & adjust bouyancy.
— Elon Musk (@elonmusk) July 7, 2018
Extremely talented dive team. Makes sense given monsoon. Godspeed. https://t.co/t5XRo3gTxK
— Elon Musk (@elonmusk) July 8, 2018
I hope you continue on with mini-sub just Incase.
— Ed ☯️ Humilitatem (@DowdEdward) July 8, 2018
Will do. Even if not useful here, perhaps it will be in a future situation.
— Elon Musk (@elonmusk) July 8, 2018
Dive Team are using CEO of SpaceX Elon Musk’s idea ‘Mini-Submarine’ in rescure operation. #ThailandCaveRescue #ThaiCaveRescue pic.twitter.com/mFYXxhXN0M
— Raveen Aujmaya (@raveenaujmaya) July 8, 2018
Pretty close. There is a nosecone on the front to protect against rocks impacting fwd air hoses with a hole on the side for hoses to exit.
— Elon Musk (@elonmusk) July 8, 2018
— Elon Musk (@elonmusk) July 8, 2018
Design based on dive team feedback (primarily Stanton): 4 air / oxygen ports front & rear, front ports protected by nosecone. Dual O-ring seal on acrylic rear plate with clear view of occupant head. Leak/buckling proof to 10X cave water pressure.
— Elon Musk (@elonmusk) July 8, 2018
Buoyancy adjusted by strapping diver weight belts around body of capsule. They’re prevented from sliding off by the 6 diver handhold attachments.
— Elon Musk (@elonmusk) July 8, 2018
Gosh, feel like you need to leverage every public situation for your own aggrandizement much? You do know there are hundreds of experts already working this across multiple counties, no? #narcissism
— Dr. John Grohol (@DocJohnG) July 8, 2018
If I am a narcissist (which might be true), at least I am a useful one
— Elon Musk (@elonmusk) July 8, 2018
— Elon Musk (@elonmusk) July 8, 2018
Aluminum shell has high thermal conductivity, so will be close to ambient. If ambient is cold, a thin layer of neoprene insulation around interior will keep occupant warm.
— Elon Musk (@elonmusk) July 8, 2018
Not a horrible idea to throw an iphone/ipod with a bluetooth speaker into the tube to keep the kids calm while they are being banged around. You can keep the kids busy while they are waiting by asking them to write down their favorite song.
— Pranay Pathole (@PPathole) July 8, 2018
Yeah, that sounds cool. Music makes things better. Calms the mind. Adding padded wall pockets for a hand radio & phone/music player.
— Elon Musk (@elonmusk) July 8, 2018
Testing underwater in LA pool pic.twitter.com/CDO2mtjP2D
— Elon Musk (@elonmusk) July 8, 2018
what are you using as ballast?
— Kyle Brubaker (@KyleBrubaker) July 8, 2018
Diver weight belts wrapped around outside. Mini-sub only weighs ~40kg dry, so easy to carry on long dry sections of cave, then add weight belts for wet sections.
— Elon Musk (@elonmusk) July 8, 2018
— Elon Musk (@elonmusk) July 8, 2018
— Elon Musk (@elonmusk) July 8, 2018
With some mods, this could also work as an escape pod in space
— Elon Musk (@elonmusk) July 8, 2018
Thanks @palicharterhigh for letting us use your pool
— Elon Musk (@elonmusk) July 8, 2018
the turnaround in designing, producing and testing this thing is amazing. your engineers must love their jobs.
— scoops (@imscoops) July 8, 2018
It is an honor to work with them
— Elon Musk (@elonmusk) July 8, 2018
Mini-sub arriving in about 17 hours. Hopefully useful. If not, perhaps it will be in a future situation.
— Elon Musk (@elonmusk) July 8, 2018
I've seen some reports that the narrowest part of the cave is roughly 72 cm by 38 cm (see attached diagram for instance). What is the diameter of the tube? If it's over 38 cm, wouldn't it get stuck in this spot? Or are these diagrams wrong? pic.twitter.com/ppO6wRJROb
— Timothy B. Lee (@binarybits) July 8, 2018
Tube diameter is 31cm
— Elon Musk (@elonmusk) July 8, 2018
Well done. Looks useful for some sort of emergency but will it make it through the tightest turns of the Thai cave? That one particularly narrow spot seems like it would be unsuitable to anything that wasn't as flexible as a human body. If it will, then awesome.
— Brandie Weikle (@bweikle) July 8, 2018
According to divers who have made the journey, this is capable of maneuvering through all passages
— Elon Musk (@elonmusk) July 8, 2018
That's good news. Huge thanks to @elonmusk and all of the specialists worldwide who have assisted the Thai government with this rescue. Indeed, good things can happen when people (especially people worldwide) work together. #AwesomeHumans #Thailand https://t.co/X7BbQyQN69
— Sean Gardner (@2morrowknight) July 8, 2018
Thanks, but we’ve not done anything useful yet. It is all other people.
— Elon Musk (@elonmusk) July 8, 2018
Simulating maneuvering through a narrow passage pic.twitter.com/2z01Ut3vxJ
— Elon Musk (@elonmusk) July 9, 2018
Is there enough space to safely turn it at the bottom to go up? pic.twitter.com/XoJ5EApnp8
— Anna Elizabeth (@Anna_online) July 9, 2018
According to divers who have made the passage, yes. However, we also made an exact replica that is inflatable, so that the entire path can be tested without risk of blockage.
— Elon Musk (@elonmusk) July 9, 2018
How many mini-subs did you make? Each round trip takes 11 hours (probably slower carrying the sub and kids), so would be good to take several of them out at a time.
— Enoch Ko (@EnochKo) July 9, 2018
A second one that is 30cm shorter is almost complete
— Elon Musk (@elonmusk) July 9, 2018
Update for 3:45 p.m. PT July 9: Looks like Musk was in on the delivery:
Just returned from Cave 3. Mini-sub is ready if needed. It is made of rocket parts & named Wild Boar after kids’ soccer team. Leaving here in case it may be useful in the future. Thailand is so beautiful. pic.twitter.com/EHNh8ydaTT
— Elon Musk (@elonmusk) July 9, 2018