Inmarsat launched its first commercially available handheld satellite phone July 16, the company announced.

The IsatPhone, an attempt to “shake up the satellite phone market,” Michael Butler, president and COO of Inmarsat, said in a statement, is a dual-mode satellite and GSM phone targeting business and personal users who travel or work in areas where local telephone networks are unreliable or nonexistent. The handsets are expected to retail at about $500, with voice call charges expected to cost less than $1 per minute.

Inmarsat is “targeting a 10 percent share of the [satellite phone] market by 2010,” Butler said.