Mars to Stay it is assumed the planet will be a magnet for settlers as wage costs will be high. Because of the labor shortage on Mars and its subsequent high pay-scale, Martian civilization and the value placed upon each individual's productivity is proposed as a future engine of both technological and social advancement. In the fifth chapter of "Mars Direct", Zubrin addresses the idea that radiation and zero-gravity are unduly hazardous. He claims cancer rates "do" increase for astronauts who have spent extensive time in space, but only marginally. Similarly, while zero-gravity presents challenges, near total recovery of musculature and immune system
Human mission to Mars space exploration proposal in the 1960s to send a crewed flight to Mars and Venus (TMK-MAVR design) without landing. The TMK spacecraft was due to launch in 1971 and make a three-year-long flight including a Mars fly-by at which time probes would have been dropped. The project was never completed because the required N1 rocket never flew successfully. The "Mars Expeditionary Complex", or "'MEK"' (1969) was another Soviet proposal for a Mars expedition that would take a crew from three to six to Mars and back with a total mission duration of 630 days. Following the Viking missions to Mars,