Launch Date May 10, 1971
Launch Site Baikonur Cosmodrome, Kazakhstan, Russia
Destination Mars
Type Orbiter
Status Unsuccessful
Nation Soviet Union
Alternate Names 1971-042A, M-71S No.170, 05221


It is widely believed that the primary purpose was to overtake America's Mariner 8 (which, ironically, was unsuccessfully launched 2 days earlier) and become the first spacecraft to orbit Mars.


None. Launch failure due to human programming error stranded the spacecraft in Earth orbit. It reentered Earth's atmosphere within two days of launch.

Key Dates

May 10, 1971: Launch

In Depth

Kosmos 419 was the first of the fifth-generation Soviet Mars probes (after those launched in 1960, 1962, 1963-64, and 1969). The original plan was to launch two orbiter-lander combinations known as M-71 during the 1971 Mars launch window.

But in order to preempt the American Mariner H/I vehicles (also known as Mariner 8 and 9), Soviet planners added a third mission, the M-71S, a simple orbiter that could become the first spacecraft to go into orbit around Mars. The orbiter could also collect data important for aiming the two landers at precise locations in the Martian system.

The spacecraft entered Earth orbit successfully, but the Blok D upper stage failed to fire the second time to send the spacecraft to Mars. Later investigation showed that there was human error in programming the firing time for the Blok D; an eight-digit code to fire the engine had been issued by an operator in reverse order. The stranded spacecraft, which was named Kosmos 419 by the Soviet press, reentered Earth's atmosphere within two days of launch.

The Soviets had promised the French that two of their Stereo instruments (instruments to measure solar radiation) would be sent to Mars. Since one was lost on Kosmos 419, Soviet officials were forced to lie about its ultimate fate to cover up the failure.


Launch Vehicle: Proton booster plus upper stage and escape stages; 8K82K + Blok D (Proton-K no. 253-01)

Spacecraft Mass: 4,549 kg

Spacecraft Instruments:

  1. fluxgate magnetometer
  2. infrared radiometer
  3. infrared photometer
  4. spectrometer
  5. photometer
  6. radiometer
  7. ultraviolet photometer
  8. cosmic-ray detector
  9. charged-particle spectrometer
  10. imaging system
  11. stereo antenna

Additional Resources

National Space Science Data Center Master Catalog: Kosmos 419

Selected References

Siddiqi, Asif A. Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, NASA, 2002.

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