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
Reed–Solomon error correction was to encode the digital pictures sent back by the Voyager space probe. Voyager introduced Reed–Solomon coding concatenated with convolutional codes, a practice that has since become very widespread in deep space and satellite (e.g., direct digital broadcasting) communications. Viterbi decoders tend to produce errors in short bursts. Correcting these burst errors is a job best done by short or simplified Reed–Solomon codes. Modern versions of concatenated Reed–Solomon/Viterbi-decoded convolutional coding were and are used on the Mars Pathfinder, Galileo, Mars Exploration Rover and Cassini missions, where they perform within about 1–1.5 dB of the ultimate limit, being the Shannon capacity.