"I think it's fair to compare this project to flying to the moon," said Lukin, who oversaw the mission and announced its success.
American and British teams are drilling to reach their own subglacial Antarctic lakes, but Columbia University glaciologist Robin Bell said those are smaller and younger than Vostok, which is the big scientific prize.
"It's like exploring another planet, except this one is ours," she said.
At 160 miles (250 kilometers) long and 30 miles (50 kilometers) wide, Lake Vostok is similar in size to Lake Ontario. It is kept from freezing into a solid block by the more than two-mile-thick crust of ice across it that acts like a blanket, keeping in heat generated by geothermal energy underneath.
Lukin said he expects the lake to contain chemotroph bacteria that feed on chemical reactions in pitch darkness, probably similar to those existing deep on the ocean floor but dating back millions of years. "They followed different laws of evolution that are yet unknown to us," he said.
Studying Lake Vostok will also yield insights about the origins of Antarctica, which is believed by many to have been part of a broader continent in the distant past.
And the project has allowed the testing of technologies that could be used in exploring other icy worlds. "Conditions in subglacial lakes in Antarctica are the closest we can get to those where scientists expect to find extraterrestrial life," Lukin said.
Drilling through the ice crust in the world's coldest environment brought major technological challenges.
Temperatures on the Vostok Station on the surface above the lake have registered the coldest ever recorded on Earth, reaching minus 128 degrees Fahrenheit (minus 89 degrees Celsius). Conditions were made even tougher by its high elevation, more than 11,000 feet (3,300 meters) above sea level.