Illustration of HMS Challenger taking measurement in ocean trench

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The first Challenger

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150 years ago an expedition that became a byword for adventure set sail. It forever changed our relationship with the sea. At its heart was the University of Edinburgh.

“On the 21st December all was pronounced ready, and the most important surveying expedition which had ever sailed from any country left Portsmouth harbour.” W.J.J. Spry, ‘The Cruise of the H.M.S. Challenger’, 1876

A Challenger mission is one synonymous with adventure and scientific exploration. But before the famous space missions that carry the name, there was the original Challenger.

21st December marks 150 years since HMS Challenger set sail to map the world’s oceans and in so doing revolutionised – and possibly created – the field of oceanography. Its undertaking could have been summed up, appropriately enough, by the iconic voice-over on the original Star Trek TV series: HMS Challenger was setting sail on a four-year mission to explore strange new worlds (at the bottom of the ocean) and to boldy go where no-one had gone before.

In 1892, the deep ocean was the “final frontier” of exploration. Nothing was known about the marine environment below about 300 fathoms (1,800 ft; 550 m). The seabed at this depth was assumed to be lifeless and uninhabitable.

Just six years before HMS Challenger set sail the first reliable transatlantic telegraphic link had been established using cables laid on the ocean floor. Such ventures were fraught with difficulty. Cable engineers had limited knowledge of the depth of the ocean and how physical properties such as temperature and salinity varied with depth. This was the prompt that led the Royal Society to fund an expedition to collect scientific data across the oceans of the world. This was to be a scientific endeavour of such ambition, scale, and cost that it was the Victorian equivalent of the Apollo missions to the Moon.

Photo of scientific team on board HMS Challenger
The scientific team on board: Charles Wyville-Thomson seated at the centre in white jacket, surrounded by the artist John James Wild, the chemist John Young Buchanan, the naturalist Rudolf von Willemoës-Suhm, and Navigating Lieutenant Tizard. Standing on the right behind Thomson is William Peniber, Thomson’s assistant, and on the left is Federick Pearcey.

An Edinburgh proposal

The vessel they acquired from the Royal Navy to undertake this first global marine research expedition was a Pearl-class corvette called HMS Challenger. This steam-assisted sailing ship was not unfamiliar with circumnavigation of the globe having been cruising the world for some 14 years by this time, with visits to the Caribbean, Australia and Fiji. In preparation for the expedition, all but two of Challenger’s 17 cannons were removed, a special dredging platform was installed, and space was made for scientific laboratories and extra cabins.

To lead the team of scientists, the Royal Society appointed Charles Wyville-Thomson, who later received a knighthood for services to science as a result of the expedition’s success.

Wyville-Thomson was one of the people to propose the idea of the expedition. Although he had only recently received the natural history chair at the University of Edinburgh, he was a veteran of several shorter ocean-faring expeditions. As part of the complement of six scientists in total, Wyville-Thomson also brought along one of his staff (and former student at Edinburgh) John Murray, who would eventually go on to get a knighthood and become a significant oceanographer in his own right. An official expedition artist, John James Wild, completed the scientific team.

The mission lasted almost four years and travelled a distance of 125,580 km –about one third of the distance from the Earth to the Moon.

World map showing measurements of deep sea sediments as measured by HMS Challenger
Chart showing the composition of the ocean floor as measured by HMS Challenger

During their circumnavigation of the globe, they collected 492 deep sea soundings, completed 133 dredges of the ocean floor, 151 trawls of the open ocean, and 263 water temperature profiles. The deepest sounding of the voyage, in the Pacific, was recorded  at 4,475 fathoms (26,850 ft; 8,184 m) deep. It is still known as the Challenger Deep, and remains the deepest part of the ocean ever recorded.

Global project

But the discovery that most surprised the team was that the deep ocean floor was not devoid of life. Among the many specimens collected, almost 5,000 of them were new species of marine life.  Their zoological samples were often transported mid-expedition back to the laboratories in Edinburgh.

Somewhat controversially for the time, and given the cost of the mission to the UK Government, Wyville-Thomson insisted that such scientific samples be sent to the leading experts wherever they might be located.  So, samples were sent around the world to more than 100 researchers, and not just to institutions within the UK.

Lithograph of a deep sea fish
Sketch of a fish captured during the voyage

As a consequence, the production of the final report took far longer than anticipated. On completion it amounted to 29,500 pages spread over 50 volumes. It is reported that it was the stress of completing the report, and justifying the enormous expense of the expedition, that lead to the untimely death of Wyville-Thomson at only 52 in 1882.

Wyville-Thomson and his legacy is commemorated in the so-called ‘Challenger Window’, a stained-glass window that dominates the apse in St. Michael’s Parish Church, Linlithgow.  He was born in the town and is buried in St Michael’s churchyard just below the window that celebrates his achievement.

Sketches of new marine life from HMS Challenger expedition
One of John Murray’s sketches of newly discovered marine life

Rich research seam

The University’s archives hold a small collection from the HMS Challenger expedition, including lithographs, engravings, photographs, and statistical and cartographical materials.

The collection also contains pencil, ink and watercolour illustrations of marine life, rock and crystal formations, and several small scenic paintings. It is a rewarding resource for researchers interested in the history of oceanography, as well as climate change, geosciences, meteorology, geography, and engineering.

This fascinating window into the voyage, however, has yet to be fully listed and is a rich seam of research waiting to be tapped.

Challenger spirit endures

Global collaboration remains vital to the ocean science conducted at the University. Edinburgh still leads deep ocean research programmes, including two recent examples.

From 2016-20 the ATLAS programme explored the oceanography and deep-sea biology of the North Atlantic Ocean. It discovered 12 species new to science and worrying evidence of how Atlantic Ocean circulation is slowing.

In 2019 the iAtlantic programme was launched with partners from across Europe working with colleagues in Argentina, Brazil, South Africa, Canada and the USA. iAtlantic is completing the most comprehensive deep and open ocean ecosystem assessment ever attempted in the titular ocean.

In the days of Challenger people assumed the ocean to be too vast to be altered by human activity but, alongside overfishing, pollution and other destructive practices, global climate change is changing the very nature of sea. Human activity is driving ocean warming, acidification and reducing oxygen concentrations.

By working across disciplines iAtlantic is identifying which regions are experiencing the most rapid climatic changes and whose ecosystems are under the most stress. This knowledge should, in theory, lead to targeted action to limit other human pressures in support of sustainable development.

Unlike in Wyville-Thomson’s time, today global ocean expeditions lasting many years are rare. Most deep-sea research takes place on expeditions that last between three and six weeks. Scientists now use robotic surveys and long-term monitoring tools that can gather data autonomously for months or even years on end. But because the deep sea remains by far the least explored realm of our planet research vessels remain essential.

Since its launch iAtlantic has completed 51 expeditions. Ten more are planned. On the anniversary of HMS Challenger sailing, 21 December 2022, iAtlantic’s latest expedition will return from exploring the deep-sea habitats of the Santos Basin in the south-west Atlantic – an expedition, like Challenger’s, that is taking place on a navy ship, the Brazilian Navy research vessel Vital de Oliveira.

HMS Challenger at sea
The HMS Challenger in dock during its 125,000 km voyage.

The other Challengers

Echoes from the original Challenger Expedition can be seen elsewhere in history. Such was its significance that several other survey vessels have continued the tradition. These include HMS Challenger II, a Royal Navy survey ship; the now retired Royal Research Ship Challenger that explored the deep-sea west of Scotland in the 1970s and 80s; the Glomar Challenger, a research ship for deep sea research and scientific drilling specifically for the University of California Scripps Institution of Oceanography; and the Space Shuttle Challenger.

And topically, in December 1972 – fifty years ago this month – Apollo 17 travelled to the Moon with the first, and so far only, scientist onboard.  Apollo astronaut Harrison “Jack” Schmidtt was a geologist but also the pilot of the Lunar Module. In recognition of the similarities to Wyville-Thomson’s  19th Century mission, he named the module Challenger. This was the last crewed vessel to visit the Moon, until the Artemis astronauts return in 2025.

And so, from Portsmouth harbour and the depths of the sea to the launch pad of Cape Canaveral and the surface of the moon, the name’s tradition of inquiry and adventure endures.

Challenger illustration Image credit: Rupam Grimoeuvre