A reel of magnetic tape containing photographic data returned by Mariner IV, July 15, 1965, Scotch brand, labeled "CXCM25 Mariner 4 Picture Data Tape, 1 file, 19 pictures, line by line format, 1 picture = 102 lines (0-191), 1 line - 192 elements (11-202), 9 track 360 single precision real [sic]," in plastic case, 295 mm diameter, 40 mm high.

Mariner IV performed the first ever flyby of Mars, and returned the first close-up images of the planet's surface. 22 photographs were taken by Mariner IV's television camera, the data being stored on tape onboard the spacecraft while it was in the shadow of Mars. Once radio contact was reestablished, the data was transmitted back to Earth. The numerical data for each picture was recorded on standard 7-track ½-inch magnetic computer tape. Processing was performed on an IBM 360/75 computer, and the original tapes were written by standard IBM tape drives. Duplicate copies such as the present example were then made on 9-track tape.