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Mission record

Mariner 7

Also known as Mariner Mars 69B, PL-691F, Mariner G, Mariner7, Mariner Mars 1969

NASA-Office of Space Science Applications · Launched

Explore trajectory

Completed · Success

The second spacecraft of the dual-spacecraft Mariner 6 and 7 mission to Mars. The Mariner 6 and 7 spacecraft were identical, and NSSDCA records this one as launched on a direct-ascent trajectory 31 days after the launch of Mariner 6. Its imaging sequence was reprogrammed as a result of analysis of Mariner 6 images, calling for the spacecraft to go further south than originally planned, take more near-encounter pictures and collect more scientific data on the lighted side of Mars. At closest approach, 05:00:49 UT on 5 August 1969, Mariner 7 was 3430 km above the martian surface, and it returned 93 far encounter and 33 near encounter images.

Destinations
Launch vehicle
Atlas-Centaur
Launch site
Cape Canaveral, United States
Countries
United States
Mission types
Flyby

Chronology

Mission timeline

  1. Launch

    Launched on a direct-ascent trajectory to Mars

    NSSDCA's launch/orbital information page gives the launch date and time as 1969-03-27T22:22:01Z. Mariner 7 was launched on a direct-ascent trajectory to Mars from Cape Kennedy Launch Complex 36A on an Atlas SLV-3C/Centaur (AC19, spacecraft 69-4) 31 days after the launch of Mariner 6. One disagreement is recorded rather than resolved: both NSSDCA pages put the two launches 31 days apart - Mariner 6's master catalog says 'Mariner 7 was launched 31 days later' - while the same catalog dates Mariner 6 to 1969-02-25 and this launch to 1969-03-27, an interval of 30 days. The catalog's own Cosmos 419 record carries the same shape.

    Earth

  2. Milestone

    Midcourse correction

    TM33-469 reports burn initiation about20:22GMT, after a commanded change to Sirius as the roll reference. Native thrust/pointing uncertainty remains separate.

    Sun

  3. Milestone

    Telemetry lost, then switched back to the high-gain antenna

    On 31 July telemetry from Mariner 7 was suddenly lost and the spacecraft was commanded to switch to the low-gain antenna. It was later successfully switched back to the high-gain antenna. It was thought that leaking gases, perhaps from the battery which later failed a few days before encounter, had caused the anomaly. The later NASA chronology instead places the anomaly onJuly30. Battery leakage or explosion is a proposed explanation; source evidence does not establish a precise impulsive state change.

  4. Milestone

    Far-encounter sequence began

    At 09:32:33 UT on 2 August 1969 Mariner 7 bagan the far-encounter sequence involving imaging of Mars with the narrow angle camera. Over the next 57 hours, ending about 5 hours before closest approach, 93 images of Mars were taken and transmitted.

    Mars

  5. Flyby

    Flyby of Mars at 3430 km

    At closest approach, 05:00:49 UT on 5 August, Mariner 7 was 3430 km above the martian surface. Over this period, 33 near-encounter images were taken. About 19 minutes after the flyby, the spacecraft went behind Mars and emerged roughly 30 minutes later. X-band occultation data were taken during the entrance and exit phases. NSSDCA's two pages do not reconcile on this encounter and the disagreement is recorded rather than resolved: the launch/orbital information page labels a Mars flyby with a closest approach time of 1969-03-27 22:22:01, which is the launch time printed at the head of that same page, while giving a periapsis of 3430.00 km. This record follows the master catalog. The same shape is already recorded on this catalog's Mariner 4 record.

    Mars

Mission architecture

Vehicles

  • Mariner 7 · Spacecraft

    Destinations: Mars

Trajectory record

Time-dependent navigation trajectory

Source states place the model at the selected time. Reconstructed flight, estimates, predictions and historical mission plans are identified by interval; gaps remain visible.

J2000 · Sun-centered display · positions interpolated between source states

Coverage: July 26, 1969 to August 14, 1969

Source records and sampling assumptions are retained with the repository data. Model attitude and surface appearance are illustrative.

  • Mariner 7: Physically reconstructed based on publicly available data · PDS PDART2017 fitted historical image geometry · source-covered Mars-flyby segment only · position accuracy expected at tens-of-kilometres scale · July 26, 1969 to August 14, 1969

Provenance

Sources

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

Data verified through September 14, 2026