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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, then gyro control

    On 8 April 1969 a midcourse correction was made by firing the hydrazine moter for 7.6 seconds. On 8 May Mariner 7 was put on gyro control to avoid attitude control problems which were affecting Mariner 6.

  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.

  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

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