Phobos 2

Chronology

Mission timeline

1. July 12, 1988, 17:01:43 UTC

   Launch

   Launched on a Proton-K

   NSSDCA's launch/orbital information page gives the launch date and time as 1988-07-12T17:01:43Z on a Proton-K from Tyuratam (Baikonur Cosmodrome), U.S.S.R. The Phobos Project page prints both launch dates together: 07 July 1988 (Phobos 1) and 12 July 1988 (Phobos 2). Phobos 2's master catalog page prints Mass: 2600 kg where Phobos 1's prints Mass: 6220 kg, and the project page prints 2600 Kg (6220 Kg with orbital insertion hardware attached).

   Earth
2. January 29, 1989, 12:55 UTC

   Orbit insertion

   Entered Mars orbit

   The later NASA chronology reports insertion at 12:55 UT into an initial 819 by 81214 km orbit at 1.5 degrees. This refines the former year-only event. The preserved historical navigation segment starts at 13:00; no earlier insertion states are invented.

   Mars
3. March 27, 1989

   Mission end

   Signal not reacquired before the approach to Phobos

   Shortly before the final phase of the mission, during which the spacecraft was to approach within 50 m of Phobos' surface and release two landers, one a mobile hopper, the other a stationary platform, contact with Phobos 2 was lost. The mission ended when the spacecraft signal failed to be successfully reacquired on 27 March 1989. The cause of the failure was determined to be a malfunction of the on-board computer. Both NSSDCA pages cited here print 27 March 1989, where the same two pages disagree by a year about Phobos 1. NASA distinguishes the missed 15:58 contact from weak RF at 17:51–18:03 without telemetry, then formal program termination on April 14. The existing navigation cutoff before March 27 remains unchanged; the later radio detections and formal end do not establish further measured positions. RGANTD quotes the 1989 commission: the computing process stopped and orientation was lost, but the underlying cause could not be uniquely established.

   Mars
4. April 14, 1989

   Milestone

   Program formally terminated

   The NASA chronology dates formal termination to April 14 after March 27 loss of useful contact. This administrative date does not extend the published orbit or imply a lander deployment.

   Mars
5. Date unknown

   Deployment

   Main propulsion module jettisoned; date unresolved

   The NASA chronology reports jettison of the Fregat propulsion module following orbital corrections. No exact release date or separate stage state is supplied. The four hydrazine tanks retained on the orbital bus are distinct from the released main propulsion module.

   Mars

Mission architecture

Vehicles

• Phobos 2 · Spacecraft

  Destinations: Mars

  • DAS (Dolgozhivushchaya AS) · Lander

  • PROP-FP hopper · Lander

  • Phobos 2 main propulsion module · Other

    Destinations: Mars