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Mission record

Zond 2

Also known as Zond2, 3MV-4 No.2

U.S.S.R · Launched

Explore trajectory

Lost · Partial success

Soviet 3MV deep-space spacecraft sent toward Mars with six experimental low-thrust electrojet plasma ion engines for attitude control. Solar-panel deployment and power problems prevented its intended encounter work. Primary histories disagree about the last contact, encounter distance and descent hardware; no successful Mars encounter or separate lander flight is established.

Destinations
Launch vehicle
Modified SS-6 (Sapwood) with 2nd Generation Upper Stage + Escape Stage
Launch site
Tyuratam (Baikonur Cosmodrome), U.S.S.R
Countries
Soviet Union
Mission types
Flyby

Chronology

Mission timeline

  1. Launch

    Launched towards Mars from a Tyazheliy Sputnik in Earth parking orbit

    NSSDCA's launch/orbital information page gives the launch date and time as 1964-11-30T13:12:00Z, recorded here at minute precision because the page prints a whole minute with zero seconds. Zond 2 was launched into a 153 x 219 km Earth parking orbit and then took a long curving trajectory towards Mars to minimize the relative velocity. The same page disagrees with itself and the disagreement is recorded rather than resolved: its Earth-orbit row gives an epoch start of 1964-11-29 13:12:00, one day before the launch date and time printed at the head of the same page and one day before the 30 November 1964 the master catalog prints.

    Earth

  2. Milestone

    Ion engines fired, 08-18 December 1964

    The electronic ion engines were successfully tested shortly after launch under real space environment conditions over the period 08-18 December 1964, which NSSDCA records as the first successful firing of ion engines on an interplanetary mission. The spacecraft carried six experimental low-thrust electrojet plasma ion engines that served as actuators of the attitude control system. Recorded at the first day of the period the page publishes.

  3. Milestone

    Second solar panel freed by firing the plasma engines

    One of the two solar panels failed due to a broken tug cord, so only half the anticipated power was available to the spacecraft. Controllers were able to finally get the second solar panel to open on 15 December 1964 by firing the plasma engines to shake it free, but this was too late for the crucial first mid-course maneuver.

  4. Loss of contact

    Communications lost in early May 1965

    After a putative (but unconfirmed) mid-course maneuver on 17 February 1965, communications with the spacecraft were lost in early May, 1965. Recorded at month precision because the page publishes no day. The same page records a competing account rather than resolving it: some accounts hold that the communications were lost a month or so after launch and no further contact was made with the spacecraft.

  5. Flyby

    Passed Mars with no contact

    The inert spacecraft passed Mars after communication was lost. NSSDCA reports1500km and5.62km/s, while the later NASA chronicle reports650000km. These incompatible values do not establish an observed encounter state.

    Mars

Mission architecture

Vehicles

  • Zond 2 · Spacecraft

    Destinations: Mars

Trajectory record

Trajectory dataset not yet available

Known dates and encounters do not uniquely determine a flight path. This mission’s sourced timeline is available above; no verified trajectory is currently published here.

What is needed to reconstruct this path?
  • A frame-qualified position and vector velocity at an epoch, or equivalent complete orbital elements.
  • Approach/departure directions and burn vectors between the reported encounters; body names and encounter distances alone are insufficient.
  • Finer event-time constraints where required by an orbital reconstruction; the stored day/month/year precision is retained.

Provenance

Sources

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

Data verified through September 13, 2026