The next phase of exploration, building on the success of the Lunar landings was a Mars mission. The US decided to allow Soviet cosmonauts to be part of the crew as a show of co-operation during the dente period. Launched in 1979 the Spacecraft based on the space stations built by the US and USSR provided living space for up to four people. Nuclear Thermal Rocket upper stage doubled the amount of payload while using less fuel. The Ship with mass of 150 tonnes (fully fueled) took seven months of transit before aerobraking in Mars orbit. Alexi Leonov and Buzz Aldrin would also enter the history books after setting foot on the Martian surface. The ice discovered on the first month of exploration was latter found to contain Mircrobial life. The crew would spend 1 year on the surface before lea