Mesbah-Yazdi has lived in virtual isolation for the past 20 years, holed up in de-facto exile in the Shi'ite holy center of Qom.

CENTERFORSECURITYPOLICY: True Fanatic

Since his initial arrest on credit card fraud charges in December 2001, al-Marri -- a legal resident of the United States -- had remained in "virtual isolation in the brig, " his attorneys said.

CNN: Accused enemy combatant moved from military custody

Since his initial arrest on credit card fraud charges in December 2001, al-Marri -- a legal resident of the United States -- has remained in "virtual isolation in the brig, " his attorneys said.

CNN: 'Enemy combatant' ruling goes administration's way

The decision by the Obama administration to criminally charge al-Marri after he spent seven years in custody -- more than five years in virtual isolation in a Navy brig in North Charleston, South Carolina -- is the latest twist in the ongoing legal saga of the only remaining "enemy combatant" held in the United States.

CNN: 'Enemy combatant' ruling goes administration's way

During the 17-plus-months of their virtual voyage, the crew took part in various studies to assess the effect their isolation was having on their psychological and physiological well being.

BBC: Simulated Mars mission 'lands' back on Earth