Russian scientists on Wednesday drilled into an ancient lake in Antarctica located 12,366 feet below the continent's icy surface.
Mission leader Valery Lukin likened the effort at Lake Vostok — one of 280 Antarctic lakes that have been sealed under miles of ice for 15 to 34 million years — to the first space flight "by technological complexity, by importance, by uniqueness."
Scientists had been racing against the clock to reach the lake by the end of the Antarctic summer, and at one point lost contact with their American colleagues for over five days, causing concern.
Vostok, described by the scientists as the "most alien lake on Earth," is one of the world's largest lakes, Fox News reported.
The Russian team, from Russia's Arctic and Antarctic Research Institute (AARI), had been drilling for weeks to reach the isolated, subglacial water, according to the Washington Post.
Some of the lakes existed in warmer times, when the continent was connected to Australia.
Vostok is thought to harbor conditions similar to those of Jupiter's moon Europa and Saturn's moon Enceladus, and the discovery of life in the lake's inky depths would significantly strengthen the prospect of discovering life on either of these icy bodies.
However, the lake is "characterized by extremes, as geothermal heat from the Earth's interior warms the lake's bottom keeping it in a liquid state.
Thousands of yards of crushing ice also insulate Vostok from the coldest surface temperatures on Earth, "while infusing it with oxygen at concentrations fifty times higher than is typical of freshwater lakes on the planet's surface," the website said.
However, because there is no light, any nutrients can only exist in small quantities.
Still, the scientists were "enormously excited about what life-forms might be found there," the Washington Post reported.
Their main concern was contaminating the lake with drilling fluids and bacteria, "and the potentially explosive 'de-gassing' of a body of water that has especially high concentrations of oxygen and nitrogen."
Late last week, when the Russian team was reported missing, Dr. John Priscu, professor of Ecology at Montana State University, told FoxNews.com via email that he had no way to contact the team and the already cold weather was set to plunge, as Antarctica's summer season was ending.
"Temps are dropping below [minus 40 degrees Fahrenheit] and they have only a week or so left before they have to winterize the station," he told Fox. "I can only imagine what things must be like at Vostok Station this week."
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