Mars flyby and rendezvous with the flyby segment transferring the crew over. (see also Mars Excursion Module (MEM)) Alternately, a flyby-only human mission is also possible, without detaching at Mars, but to slingshot around Mars and back to Earth. In July 1965, Mariner 4 achieved a flyby of Mars with a return of data, providing the public and scientists with dramatically closer images of Mars. During the flyby Mariner 4 took 21 pictures amounting to about 1% of the surface of Mars. Mars was not globally mapped until the Mariner 9 orbiter, which over the course of 1972 to 1973 took thousands
Exploration of Mars and a total of 60 pictures, Mars 2 and 3 concluded their missions. The images and data enabled creation of surface relief maps, and gave information on the Martian gravity and magnetic fields. In 1973, the Soviet Union sent four more probes to Mars: the Mars 4 and Mars 5 orbiters and the Mars 6 and Mars 7 fly-by/lander combinations. All missions except Mars 7 sent back data, with Mars 5 being most successful. Mars 5 transmitted just 60 images before a loss of pressurization in the transmitter housing ended the mission. Mars 6 lander transmitted data during descent, but