Edited sentence: A modified proposal, called "Mars to Stay" , involves not returning the first immigrant/explorers immediately, if ever.Dean Unick has suggested the cost of sending a four to six person team is one fifth to one tenth the cost of returning that same four to six person team; twenty settlers could be sent for the cost of returning four.Mars Direct, an extremely low-cost human mission proposed by Bob Zubrin, a founder of the Mars Society, uses heavy-lift Saturn V class rockets, such as the Space X Dragon, or, the Ares V, to skip orbital construction, LEO rendezvous, and lunar fuel depots