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Mission record

Mars 1969B

Also known as Mars 69B, Mars1969B, M-69 No.522

U.S.S.R · Launched

Explore trajectory

Failed · Failure

The second of the two identical M-69 class probes launched in the spring of 1969, a Soviet Mars mission never officially announced but since identified as a planned orbiter. The nominal mission plan was the same as its twin's: put the spacecraft into a 1700 x 34,000 km capture orbit around Mars with an inclination of 40 degrees and a period of 24 hours, then lower the periapsis to 500 to 700 km for a nominal three month session of imaging and data collection from orbit. The first stage of the launcher failed almost immediately and the rocket impacted and exploded 41 seconds after liftoff approximately 3 km from the launch pad.

Destinations
Launch vehicle
Proton Booster Plus Upper Stage
Launch site
Tyuratam (Baikonur Cosmodrome), Kazakhstan
Countries
Soviet Union
Mission types
Orbiter

Chronology

Mission timeline

  1. Mission end

    First-stage engine exploded 0.02 seconds after liftoff

    The first stage of the Proton SL-12/D-1-e (8K82K, #233-01 + 11S824) launcher failed almost immediately. At 0.02 seconds after liftoff, one of the six 11D43 first stage rockets exploded. The control system initially compensated for the lost engine and the launch proceeded on 5 engines until 25 seconds after liftoff at approximately 1 km altitude the rocket began to tip over to a horizontal position. The five engines shut down and the rocket impacted and exploded 41 seconds after liftoff approximately 3 km from the launch pad.

    Earth

  2. Launch

    Launched from Tyuratam

    NSSDCA's launch/orbital information page gives the launch date and time as 1969-04-02T10:33:00Z and a decay date of 1969-04-02, and prints no trajectory details. The payload was an M-69 class probe (#522) with a launch mass of 4850 kg. NSSDCA attributes the two identical M-69 probes to two different states and the disagreement is recorded rather than resolved: this spacecraft's master catalog page prints Funding Agency Unknown (Russia), while the page for its twin Mars 1969A, launched six days earlier, prints Funding Agency Unknown (U.S.S.R). This record follows the U.S.S.R attribution, which is why the twin's page is cited here.

    Earth

Mission architecture

Vehicles

  • Mars 1969B · Orbiter

    Destinations: Mars

Trajectory record

Trajectory dataset not yet available

No verified trajectory dataset is committed for this mission, so Mission Atlas renders no path.

Provenance

Sources

Each source is listed once and labeled with the mission, event, trajectory, or destination/body context it supports.

Data verified through September 2, 2026