In the middle of the South Pacific, around 2,688km (1,670 miles) from the nearest dry land, is a frigid patch of anonymous ocean – a deadly place of giant, ever-shifting swells, dramatic skies and storm-force winds. “The Southern Ocean is many shades of grey and can have huge waves… it's exciting and a little scary,” says Dee Caffari, a record-breaking British sailor and one of few people on the planet to visit this remote place.
In this distant spot, the furthest from any solid ground on Earth, there is little chance of rescue if you get into trouble. The only signs of life are triangular shark fin-like sails just above the water line in the distance – if you happen to visit at the same time as The Ocean Race, an annual round-the-world yachting competition. If not, you're out of luck.
The area is not routinely used for any other human activity, such as shipping or fishing – in fact, the nearest humans are often a very different kind of explorer: astronauts aboard the International Space Station (ISS), who are just 415km (258 miles) away when they pass overhead. This is known as the Oceanic Pole of Inaccessibility, otherwise known as Point Nemo.
To find Point Nemo on a globe, you can simply look for the vast swathe of unbroken blue between New Zealand and southern Chile – it's roughly halfway. For a more exact location, triangulate between an uninhabited atoll, Ducie Island – part of the Pitcairn Islands – in the north, Antarctica's Maher Island in the south, the Chatham Islands in the west and Chile in the east. This is a place of superlatives: the most lonely, isolated and lifeless part of the ocean … even the seafloor is some 13,000ft (2.5 miles) from the surface.
But there is another link between the icy, empty waters of this desolate place and the void of space besides the ISS: it's famous as the centre of a spacecraft cemetery – an expansive, scattered rubbish dump for obsolete items in Earth's orbit.
Between 1971 and 2018, global space powers, including the United States, Russia, Japan and Europe, crashed more than 263 space objects in the uninhabited region of the ocean around Point Nemo. The list includes the Soviet-era Mir space station and six craft from the country's Salyut programme, as well as 140 Russian resupply vehicles, six cargo transfer vehicles launched by Japan, and five from the European Space Agency (Esa). More recently, this oceanic dump is thought to have received part of a SpaceX capsule rocket. And coincidentally, its closest neighbour, the ISS, is expected to splash-land at this remote spot in just eight years.
How do spacecraft end up at Point Nemo? What twisted, broken remains are currently lurking in its inky depths? And what might future archaeologists make of it all?
A hidden record
On 23 March 2001, at 8:59am Moscow time, a group of Russian cosmonauts gazed up at the sky on the island of Fiji in the South Pacific, and waited. This was the moment the country's space agency had been preparing for for over a year; but it was soon over. For a matter of a few seconds, a sequence of golden lights could be seen blazing through the sky, leaving a smoke trail behind them. The spectacle was accompanied by sonic booms – sounds caused by shock waves formed when objects exceed the speed of sound.
This was the day the Mir space station “died”, ending its 1.9 billion km (1.2 billion miles) voyage around the world. After a series of carefully choreographed burns from its thrusters, all 134 tonnes of the world's first modular space station re-entered Earth's atmosphere. It initially crossed the threshold from outer space over Japan, then continued its fiery path before crashing into the South Pacific Ocean Uninhabited Area (SPOUA), a region 34 times the size of France surrounding Point Nemo.
But though unscrupulous online sellers immediately began selling debris from Mir – oddly, while openly admitting it was fake – and rumours continued for years that some had been found… no one has ever retrieved a single scrap. The entirety of Mir was swallowed up by the Pacific Ocean, where it remains. Any surviving fragments are likely sitting under several kilometres of water.
The question is, how much of Mir – and other defunct spacecraft that have made similar journeys – will have survived an incandescent trip though Earth’s atmosphere and abrupt ocean landing?
As objects travel back from outer space, they must run the gauntlet of the thin veil of gas molecules that surrounds our planet. Hurtling along at around 17,500 mph (28,164km/h), space debris – whether meteorites, asteroids, old spacecraft or those with human passengers – push air out of the way with such force, they break apart its chemical bonds and create an electrically charged plasma. This causes them to “burn up”, and in the case of smaller objects, cease to exist – vanishing into vapour before they hit the ground. But this is not what happens with more substantial remains.
According to Alice Gorman, associate professor of space archaeology at Flinders University, Australia, the parts of spacecraft that remain the most intact after re-entry are usually those that have been designed to withstand extremes of heat or pressure in order to serve their original purpose.
“Most often, it's the fuel tanks or the rocket boosters that survive because they've got either cryogenic fuels in them [gas propellants that have been cooled and condensed until they are liquid] or they're combusting at really high temperatures, so the fuel tanks have to be really robust to withstand those,” says Gorman. These generally represent some of the largest solid objects on board spacecraft or rockets, and they’re protected with extra insulation. “So there's a lot of stainless steel, aluminium alloys, titanium alloys…,” she says. The insulation is often made from composites of carbon, like carbon fibres, which don't burn when they get hot – even the early versions could withstand temperatures of up to 287C (549F).
However, in most cases, once spacecraft re-enter Earth's atmosphere, their ultimate fate is largely guesswork. “We sort of more or less know where they are, but we haven't seen them. No one has been out there [around Point Nemo] with a research vessel and gone down to actually look at their condition,” says Gorman.
A scattering of debris
Esperance Museum in Western Australia offers some clues. This obscure regional attraction, located in the coastal town of the same name, contains an eccentric and seemingly random jumble of artefacts – an old motorbike, a 19th-Century train carriage, assorted agricultural machinery – but this is not what it's most famous for.
The main draw can be found in a plexiglass cabinet and metal pen, masquerading as a mass of junk carefully labelled with laminated paper. There's a sightly crumpled water tank made of cylindrical steel, a mysterious titanium sphere that would once have contained nitrogen, a steel food freezer, and various unusually shaped chunks of rusted metal, among a handful of scraps of ragged sponge. The largest object is a metal oxygen tank, wrapped in clear plastic, some 6ft-long (1.8m). These are among the largest fragments ever found of Skylab, the first US space station.
It was launched into Earth's orbit on 14 May 1973 – and returned to its home planet just six years later. Nasa had initially hoped that Skylab could continue its mission for longer, but its orbit degraded faster than expected, and by early 1979 it became clear that this 77 tonne station was not remaining in space – whether humanity liked it or not.
Like with all large space objects, it was deemed vital to control Skylab's descent as much as possible, so that it could be ditched in the ocean, far away from human activity. But no one had thought to plan for its disposal – and there was little Nasa engineers could do to steer the rogue space station on its journey back to Earth. On its final day, Skylab performed a “deorbit” manoeuvre, firing its engines to slow itself down so that it could tumble out of the sky and – hopefully – disappear into the Indian Ocean just southwest of Australia. But it didn't go to plan.
In the early hours of the morning on 11 July 1979, there were sightings of falling Skylab debris across central Australia. Locals reported finding telescope mountings, bits of fuel tanks, a lead film vault, a 22ft-long (6.7m) airlock shroud – a shield that protects the airlock chamber – and a large oxygen tank, strewn over outback scrub and farmland. In all, Nasa said, at least 38 pieces of debris weighing more than 1,000lb (454kg) each had been found.
In the end, most of this space waste ended up landing in the Shire of Esperance – and the region invoked a new law to issue Nasa with a $400 (£329) fine for littering, which is technically outstanding to this day. But though the incident was embarrassing for the space agency, it allowed the debris from the re-entry of a large object to be examined. The fallout was not just a congealed mass of metal – surprisingly complex structures survived, including a hatch door.
So how large could the spacecraft chunks at Point Nemo be?
In the case of Mir, at the time of its re-entry, it was predicted that this giant space station – which consisted of a central core around 13m (43ft) long, and five laboratory modules – would break into up into 1,500 pieces of debris. Experts suggested that the largest portions could possibly even be the size of a small car. These would include fuel tanks, batteries, bulkheads and storage boxes, all of which are deep under the sea around Point Nemo. Even some lighter items like sheet aluminium and foam insulation may have survived.
When the ISS descends back to Earth in 2031, it's more important than ever that the debris falls over an uninhabited area like Point Nemo – it weighs around 400 tonnes. And there are already plans afoot to achieve this. “Nasa has released a request for proposal from US industry for the US Deorbit Vehicle (USDV),” explained a representative from the Johnson Space Centre in an email.
The deorbit vehicle would dock to the ISS around a year before its planned re-entry, ready to be used in its final days. This specialised spacecraft will control where the space station crosses over into Earth’s atmosphere,, and therefore where it ends up. Nasa has predicted that while some parts of the ISS will burn up, denser or more heat-resistant sections are likely to survive. This includes trusses, a sequence of steel structures that form the backbone of the space station and can be up to 18.3 m (60 ft) long
A historical record
All this means that Point Nemo is now – and will likely remain – a goldmine for future archaeologists. “You would study them [spacecraft graveyards] kind of the same way that you would something like a rubbish midden, or a shell midden or something like that,” says Gorman. These accumulations of waste thrown away by humans hundreds or thousands of years ago are often exploited by archaeologists to learn about how people lived, including what they ate and what they valued – in the past.
From studying ancient shell middens, archaeologists have managed to reconstruct the behaviour of ancient coastal hunter-gatherers, who relied on seafood such as whelks and mussels to survive. Though the act of discarding something – whether a spacecraft or a shell – may seem careless, Gorman describes these dumps as a deliberate accumulation of artefacts. “And one thing you can do is look at the how that changed over time, ” she says. “Like, which are the earliest ones, which are the latest ones? What kind of technological or material changes do we see in the intervening years?”
In 1,000 years, even the current shift towards reusable rockets may be written into the debris at Point Nemo. “At some point, if you were doing a global survey of what's in the ocean around Earth, you would notice that there was a radical drop off in numbers of ocean disposals say after 2013,” says Gorman. “That's a change in value – people are starting to value recycling, reusing and minimising environmental harm,” she says.
In fact, Gorman views the artefacts at Point Nemo as an important record of early space exploration. And luckily, it probably isn't going anywhere. Not only are the remains strewn across the South Pacific likely to be remarkably intact, but they also just so happen to have ended up in some of the best conditions for preservation.
The waters around Point Nemo are thought to be among the most lifeless on Earth for the same reason they’re a good spacecraft cemetery: they're far from land, which tends to leach nutrients into the oceans. This, combined with the natural lack of oxygen in the deep ocean, the freezing temperatures and total lack of sunlight, make for ideal conditions – decreasing the rate of chemical processes such as rusting.
“The main impact will be just chemical reactions of saltwater with the materials,” says Gorman. But again, many important spacecraft components are actively designed to be inert and unreactive, with metals such as stainless steel and titanium and aluminium alloys. “That's what you want from a fuel tank,” she says.
Gorman speculates that even in 1,000 years, the spacecraft at Point Nemo would be in relatively good condition. “This is something you find with historic shipwrecks – they're very well preserved under the water. And it's when they're bought to the surface that decay starts to set in.”
So, though no one has managed to track down the intriguing space artefacts at Point Nemo just yet, there are probably plenty there, bathed in total darkness on the seafloor. For now at least, they have swapped the bleak emptiness of outer space for another lonely void.
— CutC by bbc.com
