It is the first American planetary expedition in 11 years.

He died during a 1953 American expedition to K2.

An American expedition to Oahu occurred in late 1873 to early 1874.

The American expedition to Mars had been planned for decades.

But on academic grounds, the North American expeditions are the most valuable.

The first casualties of the summer occurred on an American expedition.

An American expedition sent 25 men into the Arctic to collect data - only 6 returned.

However, two American expeditions in 1938 and 1939 had come closer to success.

In late 1994 and early 1995 the first American expedition took place.

Among his major assignments were the American polar expeditions in the 1950's and the early stages of the space flight program.