Vostok Station with the 5G drill tower where the drilling crew has touched Vostok Lake (Photo courtesy Russian Geographical Society)
"An event that has been keeping the world scientific community on tenterhooks for the last few months occurred on February 5 at 8:25 pm Moscow time," Alexander Yelagin, chief of Russia's Vostok scientific station, told the Russian institute.
"Specialists with the glaciological and drilling unit of the 57th Russian Antarctic expedition through deep ice borehole 5G penetrated the relict waters of sub-glacial Vostok," said Yelagin.
A source at the Russian Meteorological Agency also confirmed the breakthrough.
Lake Vostok is 300 kilometers (186 miles) long, up to 80 meters (262 feet) wide and up to one kilometer (.6 of a mile) deep.
In early 2011, the drilling project yielded the deepest ice core ever recovered, at a depth of 3,720 meters.
Vostok Station ice core depository, a frozen archive of Earth's climate (Photo courtesy Russian Geographical Society)
Russian geographer Andrey Kapitsa was the first to suggest the existence of a subglacial lake in this region and named it Lake Vostok. To identify the lake, Kapitsa used seismic soundings in the region of Vostok Station made during the Soviet Antarctic Expedition in 1959 and 1964 to measure the thickness of the ice sheet.
Deep drilling in the area of Vostok Station began during the 1970s, when the existence of the lake was unknown.
In 1974, British scientists in Antarctica performed an airborne ice-penetrating radar survey and detected strange radar readings at the site, but did not immediately identify them as a liquid, freshwater lake below the ice.
In 1991, Jeff Ridley, a remote-sensing specialist with the Mullard Space Science Laboratory at University College London, directed the European satellite ERS-1 to turn its high-frequency array toward the center of the Antarctic ice cap. It confirmed the 1974 discovery, but it was not until 1993 that the discovery was published in the "Journal of Glaciology."
The drilling was halted in 1996 at a depth of 3,623 meters, by the request of the Scientific Committee on Antarctic Research that expressed worries about possible contamination of Lake Vostok by a freon and kerosene-based anti-freezing agent used by the drilling team.
Vostok glacier drilling crew, January 21, 2011. 5G hole’s depth: 3,700 meters.
Lake ice recovered by deep drilling is of interest for preliminary investigations of lake chemistry and bedrock properties and for the search for indigenous lake microorganisms in the lake's liquid layer. This latter aspect is of potential importance for the exploration of icy planets and moons.
At the end of 2012 when the new Antarctic summer starts, the Russian team plans to send a robot into the lake to collect water samples and sediments from the bottom.
Scientists hope Lake Vostok can reveal new forms of life and show how life evolved before the Ice Age. Millions of years ago, dinosaurs roamed across what was then a forested continent, migrating from Australia and other land masses that were connected to Antarctica at the time. The remains of several Antarctic dinosaurs have already been found.
The Russian Geographical Society calls the Vostok Station "the pole of cold." The average annual air temperature there is minus 56° Celsius, or minus 69° Fahrenheit. It is very dry with an average annual precipitation of just 25 millimeters.
Located 3,490 meters above sea level at the center of the East Antarctic Ice Sheet - about 1,300 kilometers (808 miles) from the Geographic South Pole and 1,400 kilometers (870 miles) from the coastline - Vostok Station is within the Australian Antarctic Territory. As a signatory to the Antarctic Treaty System, Australia does not exercise sovereignty over the territory.