Mission Atlas
← Mission directory

Mission record

Mariner 2

Also known as P 38, 1962 Alpha Rho 1, Mariner R-2, Mariner-Venus 1962, Mariner2

NASA-Office of Space Science Applications · Launched

Explore trajectory

Completed · Success

The backup for the failed Mariner 1 mission and, in NSSDCA's words, the first spacecraft to successfully encounter another planet. Its objective was to fly by Venus and return data on the planet's atmosphere, magnetic field, charged particle environment and mass, and to measure the interplanetary medium during the cruise. It approached Venus from 30 degrees above the dark side and passed below the planet at its closest distance of 34,773 km on 14 December 1962. NSSDCA credits it with finding a slow retrograde rotation rate for Venus, hot surface temperatures and high surface pressures, a predominantly carbon dioxide atmosphere, continuous cloud cover with a top altitude of about 60 km, and no detectable magnetic field.

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

Chronology

Mission timeline

  1. Launch

    Launched from Cape Canaveral on an Atlas-Agena B

    NSSDCA's launch/orbital information page gives the launch date and time as 1962-08-27T06:53:14Z. The master catalog records that after launch and termination of the Agena first burn the Agena-Mariner was in a 118 km altitude Earth parking orbit, and that the Agena second burn some 980 seconds later, followed by separation, injected Mariner 2 into a geocentric escape hyperbola at 26 minutes 3 seconds after lift-off.

    Earth

  2. Milestone

    Separated; appendages stowed

    Postflight estimated spacecraft-Agena separation clock; fold angles and stowed envelope are approximate. The source explicitly labels its event-time column as estimated after flight.

    Earth

  3. Milestone

    Mariner separated from Agena B

    SP-59 gives the spacecraft separation in its postflight estimated-time column. The released Agena is a distinct vehicle. Its subsequent orbit cannot be reconstructed by duplicating Mariner's state; a separation state and the stage's later maneuver history are required.

    Earth

  4. Milestone

    Panel deployment; reference pose

    The original report estimates the deployment command at 07:37:04 GMT. Retain the stowed reference during the unresolved transition; no intermediate hinge motion is claimed. The source explicitly labels its event-time column as estimated after flight.

    Earth

  5. Milestone

    Arrays unfolded; antenna stowed

    The postflight table estimates full array deployment at 07:38:07 GMT. The antenna remains under the bus before its separately reported extension. The source explicitly labels its event-time column as estimated after flight.

    Earth

  6. Milestone

    Antenna extended; pointing illustrative

    The report estimates antenna extension with Sun-acquisition initiation at 07:53:07 GMT. Actual continuous hinge motion, later tracking angles and spacecraft attitude are not reconstructed. The source explicitly labels its event-time column as estimated after flight.

    Earth

  7. Flyby

    Passed Venus at 34,773 km

    The master catalog and launch/orbital information page both report 19:59:28 UT on 14 December 1962, but disagree on closest-approach distance: the master catalog gives 34,773 km, while the orbit page gives 5.71 RV using its stated 6,052 km radius. The catalog retains the master catalog value. An independent NAIF-hosted JPL reconstructed SPK, fit to encounter Doppler data using DE405, reports 40,948 km at 19:55:19 CT at Venus; its 19:57:57 UTC is explicitly the time at Earth and is not the spacecraft's physical Venus closest-approach time. Direct minimization of that SPK against its DE405 Venus solution gives 1962-12-14T19:54:37.395 UTC and 40,948.443 km. Re-expressing the same spacecraft solution against the simulator's DE440 Venus ephemeris gives 19:54:47.760 UTC and 41,057.769 km. The source-system change and disagreement with NSSDCA remain unresolved; neither computed time replaces the NSSDCA event clock. The JPL kernel is a general historical reconstruction, not precision navigation, and its Doppler residual is not a position covariance.

    Venus

  8. Loss of contact

    Last transmission received

    The master catalog records that the last transmission from Mariner 2 was received on 3 January 1963 at 07:00 UT and that Mariner 2 remains in heliocentric orbit. The launch/orbital information page prints that same date under a heading that does not describe it, as Decay Date: 1963-01-03, for a spacecraft its own trajectory rows put in solar orbit with no epoch stop.

Mission architecture

Vehicles

  • Mariner 2 · Spacecraft

    Destinations: Venus

  • Mariner 2 Agena B upper stage · Other

    Destinations: Venus

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: August 27, 1962 to December 31, 1962

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

  • Mariner 2: Reconstructed · August 27, 1962 to December 31, 1962

Provenance

Sources

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

Data verified through October 5, 2026