Last week, the Russian program to drill to Lake Vostok in Antarctica reached the lake waters at last. The techniques used have not been widely reported, and the different teams trying to reach subglacial lakes in Antarctica advocate different methodologies. In the Vostok case, water from the lake flowed up the bore hole (that has been kept open with kerosene over the period of the drilling), and this water will be allowed to freeze and will be sampled as ice with a separate coring effort next year. This way the scientists expect that nothing entered the lake, only some water came out.
A nice summary can be read in the Nature news report about the coring that was published yesterday: