China is going full Jules Verne as it prepares to go where no drill has gone before. As part of its Deep Ocean Drilling Program, the special-built Meng Xiang (梦想号, "Dream") drill ship is gearing up for a multi-year effort to pierce the Earth's crust.
Ever since Homer's The Odyssey, storytellers have been fascinated with traveling beneath the surface of the Earth into the mysterious underworld. Dante wrote of a day trip to Hell at the Earth's core and in 1864 Verne published his science fiction classic Journey to the Center of the Earth (Voyage au center de la Terre), where a team of adventurers descend through the Earth's crust and embark on all sorts of fabulous adventures.
These were followed by the likes of Edgar Rice Burroughs, John Wyndham, H.P. Lovecraft, and many others in novels, short stories, comics, films, Saturday morning serials (with singing cowboys!), and television shows. And fictional menaces returned from their trips with the world being menaced by giant radioactive blobs, prehistoric lizard men, giant pterodactyls leveling Tokyo (as they do), and all sorts of variants of mole people and lava men.
However, getting to the Earth's core in real life is a lot harder than climbing down an extinct volcano or putting together an iron mole to get you there.
If you try going down in a natural cavern, the deepest you'll get is in the Veryovkina Cave in Abkhazia, Georgia with a depth of 7,257 ft (2,212 m). It wasn't even discovered until 1968 and took half a century to explore properly. As for digging, well, that's been pretty slow in progressing. In 1862, the deepest hand-dug excavation was Woodingdean Well in Brighton and Hove, England – and it only reached 1,285 ft (392 m). Oil and gas drilling kept setting new records and the Empire gold mine in California had plumbed to 11,007 ft (3,355 m) when it closed in 1956.
However, the Chinese are going for something far more ambitious. What they want to do is follow in the footsteps of the American Project Moho of the late 1950s and early 1960s, which wasn't just trying to drill deep, but open an entirely new geological frontier.
Project Moho was named after the Mohorovičić discontinuity or Moho, which is a fundamental boundary within the Earth's interior. Discovered in 1909 by Croatian seismologist Andrija Mohorovičić, it's the point where the Earth's crust and the mantle meet and interact. So far, all we know about it has come from seismograph readings and inferences from minerals brought up by volcanic activity, but it's essentially where the lighter silicate rocks of the crust give way to the much denser ultramafic rocks of the mantle.
What Project Moho aimed to do was drill down to the Moho and return samples that scientists would be able to study directly, as well as studying the properties of the Moho directly. It was also designed to look for evidence of continental drift – an idea that was then just starting to shift out of crackpot territory and into the scientific mainstream.
That was all well and good, but it was a bit like exploring the Moon in that the scientists and engineers behind Project Moho had to develop whole new drilling techniques, core retrievals, and drill management just to get there. Worse, the Moho isn't at a uniform depth beneath the surface. Under the continental crust, the Moho is from 12 to 56 miles (20 to 90 km) down. Under the ocean floor, it’s much shallower, just three to six miles (five to 10 km) down. This offered the benefit of drilling through less rock, but came with the challenge of operating a drill rig from a ship positioned above several thousand fathoms of open ocean.
Long story short, when Project Moho terminated after several drilling phases as well as cost overruns and political infighting, it had reached a maximum depth of 601 ft (183 m) off the coast of Guadalupe Island, Mexico at a sea depth of 11,700 ft (3,600 m). This would later be beaten by the Kola Superdeep Borehole (SG-3) that drilled in the Murmansk Oblast, USSR in 1979, also trying to reach the Moho, that reached a depth of 39,720 ft (12,00 m) – and that was through the much thicker continental crust, getting only one-third of the way.
Bear in mind that while other drilling operations have gone deeper, that is in terms of the length of the drilling, which can curve away from straight down, while Project Moho and SG-3 are measured in true vertical depth.
Now China is stepping up to the plate with more at stake than just reaching the deep-drilling equivalent of reaching the North Pole or finding the source of the Nile. As part of its wider global ambitions, Beijing wants to establish China as a major player in deep-sea exploration, drilling, mining, and related fields.
China's attempt to reach the Moho comes under its Deep Ocean Drilling Programme, which is a multi-decade effort dedicated to Earth sciences; deep-sea biosphere research; the study of undersea earthquakes and similar hazards; the study of plate tectonics, paleoceanography and climate change; seeking out and exploiting deep-water oil and gas reserves; and deep-sea mining.
Beyond that, it's also tasked with making China dominant or self-sufficient in the technologies required for these fields on a global or at least on a regional scale, as well as securing new energy sources and increasing China's maritime power.
There are a number of components of this program, but the flagship is the Meng Xiang. Described as China's first domestically designed and built deep-ocean drilling vessel, it was officially commissioned in Guangzhou on November 17, 2024 and after it completes fitting out and sea trials, it's expected to begin drilling operations in the South China Sea later this year, which will continue until 2035.
Aside from penetrating the Earth's crust (hopefully without disturbing some science fiction horror), it's also a multi-purpose vessel capable of deep-sea resource exploration with a focus on finding reserves of oil and gas as well as natural gas hydrates – the famous flammable ice found in very cold areas. It can also retrieve deep-ocean geological cores, and act as a testbed for new technologies.
The Meng Xiang measures 560 ft (180 m) long with a beam of 108 ft (33 m) and displaces about 42,600 tonnes. Carrying a crew of 180 officers, ratings, and researchers, it has an endurance of 120 days without resupply and a range of 15,000 nautical miles (27,780 km). As for drilling, it can drop a drill pipe thread weighing 907 tonnes some 36,000 ft (11,000 m) beneath the sea surface and can operate in rough sea conditions in excess of a Force 12 typhoon.
It also boasts a special mud recycling system to reduce fouling of the local waters during drilling and what is claimed to be the world's first automated shipborne core sample storage system – not to mention room for nine advanced onboard scientific laboratories in fields including geology, geochemistry, microbiology, ocean science, and drilling technology.
It's a lot of sophisticated hardware and the Meng Xiang will need it. The Moho isn't just deep and it may not even be near the molten core, but it marks a place where the usual rules of geology and mineralogy may not break down, but they do get severely bent for their troubles.
The pressure and temperatures at such depths are staggering. If you're looking at the Moho under the ocean floor, the pressure can reach 2,000 atmospheres and the temperatures peg at 302 to 572 °F (150 to 300 °C). Under the continental shelf, it comes to 10,000 atmospheres and a balmy 932 to 1,292 °F (500 to 700 °C). Under such conditions, the pores of the rocks collapse and they become much denser and water is squeezed out of its matrix, pushing metamorphic processes that convert the rocks into new minerals as they try to stabilize.
More important from a drilling point of view is that the rocks near the Moho change their behavior. They first become more brittle, then more plastic until a drill bit forcing its way down isn't so much cutting as chewing through a sort of high-temperature, high-pressure putty as it becomes viscous – not to mention partially melting in places.
To a geologist or a mineralogist, this is fascinating, but to a deep-drilling engineer on the deck of a ship trying to hold station to precise tolerances in a tossing sea, it comes under the heading of aggravation.
Though China emphasizes that the Meng Xiang will be open to international collaboration, the whole project is skirting controversy. Deep sea operations that were supposedly innocent have, in the past, acted as a cover for some pretty devious intelligence operations, so it would be surprising if the Chinese Moho project didn't attract at least a certain degree of suspicion.
There's also the fact that China has been pushing an aggressive policy of extending its claims over the South China Sea that have already got it into hot water. In 2014, the Chinese Hai Yang Shi You 981 oil rig was claimed to infringe on Vietnamese waters and future drilling by the Meng Xiang could invite similar controversy.
Then there is the fact that the Meng Xiang is an oil and gas exploration vessel. If it is suspected that part of its scientific work secretly includes energy prospecting in the disputed waters around Vietnam, the Philippines, Malaysia, or Brunei in the South China Sea, it could result in diplomats putting in for overtime in the coming years – especially if the Meng Xian is seen as an expansion of Chinese maritime capabilities or an attempt to assert territorial claims. At the very least, the Meng Xiang could find itself trailed by ships of other nations that just "happen" to be in the vicinity and seem to carry an awful lot of telescopes and antennae.
So, when it comes to the Meng Xiang, are we talking innocuous Jacques Cousteau, world-smashing Sir Arthur C Clarke, or Cold War Alistair Maclean?
Only time and events will tell.