Kosmos 419 (Russian: Космос 419 meaning Cosmos 419) was launched by the Soviet Union on May 10, 1971. Mars was at its closest to Earth since 1956 and, in May that year, both the Soviet Union and the United States made new attempts to reach the Red Planet. The payload however failed to separate from the fourth stage of the launch vehicle, and was subsequently designated Kosmos 419. It reentered Earth's atmosphere two days after launch.
The Soviet probe was intended to overtake the United States probes, Mariner 8 (which had failed at launch two days earlier) and Mariner 9 (that executed a fully successful mission, and was the first spacecraft to be placed in orbit around another planet), in the aim of becoming the first Mars orbiter. Kosmos 419 was a part of the Soviet Union's Mars probe program M-71, of which there were 3 missions in 1971, including Mars 2 and Mars 3 in May 1971, only days after Kosmos 419. In a difference of two other members of project M-71, Kosmos 419 was an orbiter only.
The Soviet Union had previously failed in attempts to reach the Red Planet in the 1960s: by the first generation of 3 martian probes (Marsnik program) in 1960, second generation of 2 martian probes (Mars 1 and Zond 2) in 1962 and 1964, and 2 probes (Mars 1969A and Mars 1969B) in 1969 with similar to M-71 heavy design.
The SL-12/D-1-e Proton booster successfully put the spacecraft into low earth parking orbit (174 km x 159 km) with an inclination of 51.4 degrees. However, the Block D stage 4 then failed due to a bad ignition timer setting: the timer, intended to start ignition 1.5 hours after orbit was reached, had been erroneously set for 1.5 years. The orbit subsequently decayed and the spacecraft re-entered Earth's atmosphere 2 days later on 12 May 1971. The mission was designated Kosmos 419.
"Beginning in 1962, the name Kosmos was given to Soviet spacecraft which remained in Earth orbit, regardless of whether that was their intended final destination. The designation of this mission as an intended planetary probe is based on evidence from Soviet and non-Soviet sources and historical documents. Typically Soviet planetary missions were initially put into an Earth parking orbit as a launch platform with a rocket engine and attached probe. The probes were then launched toward their targets with an engine burn with a duration of roughly 4 minutes. If the engine misfired or the burn was not completed, the probes would be left in Earth orbit and given a Kosmos designation."