File:Beyond the Deep, to the most remote place on Earth (9527779732).jpg

I recently met Bill Stone and learned of his interest in exploring inner and outer space. He gave me his book, Beyond the Deep, that documents his harrowing 1994 expedition to the most remote place on Earth. He spent decades developing rebreathing dive technology to haul deep into the cave network to navigate through the lower flooded tunnels (he called the units Cis-Lunar, a nod to their space applications).

Prior to Bill's expedition, no one had seen what lies beyond Sump 1 in the middle of the map, now 57km long.

I just finished the book today, and it is gripping, like a Michael Crichton sci-fi thriller, where truth is stranger than fiction. Spending months deep underground with a series of support camps, a team of 44 people allowed Bill and his girlfriend Barbara to push the frontiers of the unknown. Along the way, one team member drown, and the extraction of the corpse tested their limits. They were racing against the wet season, when the underground tunnels become torrential rivers. For days, they remained separated and trapped in an air bell as an early rain swelled the water levels, blocking passage back to the surface. Just when it seems like it could not get any more crazy, it does.

I wrote to Bill to ask if anyone has pushed beyond his record exploration, and someone just has. He writes:

“After almost 20 years a British expedition returned to San Agustin in Huautla just this past spring with over 50 team members. We supported them with logistics and guidance and our team was their rescue call out backup as we were working on the opposite side of the same mountain range at J2. Two of their divers made it to Sump 9 in San Agustin, the limit of where we reached in 1994. One of them did a 400 meter long exploratory dive into the large tunnel which, quite surprisingly, continued to descend beyond the range of their diving equipment at a depth of 81 meters underwater. It was still going down where they stopped.... underwater. The total depth of the cave is now -1,545 meters."

"There have been discussions over the possibility of sending a man-portable micro-autonomous underwater vehicle (AUV) in to explore and map beyond the human limit. The main issue with manned exploration now is decompression.... a long time spent at 80 meters or deeper underwater leads to an exponentially increasing required decompression schedule which can easily exceed the range of even today's backpack closed-cycle life support systems. The only way around that is to use propulsion vehicles, underwater habitats and pressurized transfer chambers -- all of which we have used but which require massive infrastructure that cannot be carried to this exploration site. My company designs and builds AUVs; the only question is whether they would survive the transport.”