An Alaskan brown bear sow and cub cross a stream in Glacier Bay National Park, Alaska, in this undated photo.
The mission will seek to unlock clues about the changing Arctic climate and the shifting ice conditions that affect ocean ecosystems.
Exploratory drilling is scheduled for July in the waters off Alaska's northern shore. Environmental groups, reeling from the Gulf of Mexico BP oil spill, are fighting to put those plans on hold.
Oil companies are eyeing Alaska's largely untapped outer continental shelf. Critics say that's another Exxon Valdez waiting to happen.
The Arctic ice cap will disappear? A new study says the Arctic Ocean could be ice-free during the summer months in less than 20 years.
If the pattern continues, warming effects could reach up to 900 miles inland, melting permafrost
Lease sales could produce 15 billion barrels of oil, but environmentalists say drilling would threaten already melting habitat.