The probes, however, were both destroyed in separate launches in early 1969.

[2] After the landing of Venera 4 in October 1967, NPO Lavochkin looked at landing a larger probe on Mars with an Orbiter.

Using the newer Proton-K (Blok-D), they could beat NASA's upcoming Mariner 6 and 7 probes in the 1969 Mars launch window.

[5] The second and last launch (2M No.522)[1] on April 2, 1969, failed when the Proton-K Blok-D carrying it first had smoke appearing from the first stage[5] before it veered west, crashing near Site 81/23.

[2] After the failure of M-69, NPO Lavochkin redesigned Mars-69 to allow for a landing on Mars in 1971.