Radiation on a Mars trek would be higher than what crew members cocooned inside the International Space Station typically face about 200 millisieverts per year.
"Transocean's rig crew accepted the direction of BP well site leaders to proceed in the face of clear danger signs at a tragic cost to many of them, " said assistant attorney general Lanny Breuer.
Italian prosecutors wanted the crew of the jet tried in Italy, but an Italian court ruled they should face court-martials in the U.S., in accordance with NATO treaties.