Venera 12

Chronology

Mission timeline

1. September 14, 1978, 02:25:13 UTC

   Launch

   Launched on a Proton-K booster from Baikonur Cosmodrome

   The launch/orbital information page and the descent craft page both print the launch time as 02:25:13 UT on 1978-09-14. The flight platform page names the booster in its own text as a Proton-K while all three pages print Proton Booster Plus Upper Stage and Escape Stages under Launch Vehicle. THE TWO ENUMERATION SPINES DISAGREE ON WHAT THIS SPACECRAFT WAS: NSSDCA's general chronology classifies it Venus Orbiter and Lander while its Venus-specific chronology classifies the same flight Venus Flyby Bus and Lander. The descent craft page settles it in NSSDCA's own words - the descent craft was mounted on a flyby bus, not an orbiter as on earlier missions - and this record follows the pages rather than the chronology row.

   Earth
2. December 19, 1978

   Deployment

   Descent craft separates from the flight platform

   The descent craft page records that the descent module separated from its flight platform on 19 December 1978, and the flight platform page records the ejection as two days before encounter; it entered the nightside Venus atmosphere two days later at 11.2 km/sec.

   Venus
3. December 21, 1978

   Flyby

   Flight platform passes Venus at approximately 34,000 km altitude

   The flight platform page records the encounter with Venus on December 21, 1978 at approximately 34,000 km altitude, and that it acted as a data relay for the descent craft for 110 minutes. Recorded at day precision because the page hedges the altitude with the word approximately and its launch/orbital information page prints a closest approach time of 1978-12-21 00:00:00, a midnight placeholder rather than an observed time. That page's own 6.62 RV, against its stated 1 RV = 6052 km, is about 40,000 km rather than the 34,000 km the master catalog prints, and the disagreement is recorded rather than resolved. READ AS THE PERIAPSIS BY INFERENCE, NOT BY READING: the committed excerpt flattens that table to five headers followed by three values, Periapsis Apoapsis Period Inclination Eccentricity 6.62 RV 0.000 degrees 0.00000, so which column 6.62 RV sits in cannot be read off the excerpt and is taken from its position as the first value.

   Venus
4. December 21, 1978, 03:30 UTC

   Landing

   Soft landing at 7 S, 294 E

   The descent craft page records a soft landing on the surface at 03:30 UT on 21 December after a descent time of approximately 1 hour, with a touchdown speed of 7-8 m/s at 7 S, 294 E. That sentence prints no year, and the year comes from the descent craft's own launch/orbital information page, which prints a Lander row with an epoch start of 1978-12-21 03:30:00 and a Decay Date of 1978-12-21 - a single page printing a complete date and time, not a time taken from one sentence and a date from another.

   Venus
5. April 18, 1980

   Loss of contact

   Final contact with the flight platform

   The flight platform page records that Venera 12 took UV spectrometric measurements of Comet Bradfield in February and March of 1980 and measured gamma-ray bursts from space, and that after a final communication session on 18 April 1980 the orientation system failed and contact was lost.

6. Date unknown

   Milestone

   Two mid-course corrections en route to Venus

   Both pages record two mid-course corrections, on 21 September and 14 December. Carried without a timestamp because the sentences that print those days print no year.

Mission architecture

Vehicles

• Venera 12 Flight Platform · Spacecraft

  Destinations: Venus

  • Venera 12 Descent Craft · Lander · completed

    Destinations: Venus