1978-078A
The second Pioneer Venus probe, the Pioneer Venus Multiprobe or Pioneer Venus 2 was launched at 0733 on 1978 Aug 8 by Atlas Centaur from Cape Canaveral. The Centaur placed the PVM on a Type 1 trajectory to Venus. The initial trajectory would have led to a 14000 km altitude Venus flyby. Trajectory correction maneuvers were carried out on Aug 15, Oct 19, and Nov 9.
The large Sounder Probe was released at 0237:13 on Nov 16. At 1306:29 on Nov 20 the three small probes were separated. The Multiprobe Bus made a trim maneuver at 1137:12 on Dec 9, and at 2021:52 on Dec 9 began its entry at a -9.4 deg angle over -38.6 deg latitude, 291.8 deg longitude. At 2022:55 it burnt up at 110 km altitude, at -41.2 deg latitude, 284.1 deg longitude.
| PVM | |||
| Date | Time | Event | Orbit |
|---|---|---|---|
| 1978 Aug 8 | 0733 | Launch by Atlas Centaur AC-51 | CC LC36 |
| T+2:19 BECO | |||
| T+2:22 Booster sep | |||
| T+3:04 Insulation panels | |||
| T+4:11 Atlas SECO | |||
| T+4:13 Atlas sep | |||
| 0737 | T+4:23 Centaur MES-1 | ||
| 0742 | T+9:42 Centaur MECO-1 | 165 x 170 x 28? | |
| 18 min coast | |||
| 0800 | T+27:30 Centaur MES-2 165 km Vrel 7.406 km/s | ||
| 0802 | T+29:38 Centaur MECO-2 186 km Vrel 10.157 km/s | ||
| 0804 | T+31:53 Centaur sep 361 km Vrel 10.851 km/s | ||
| 0805 | T+32:02 Spinup to 15 rpm | ||
| Control to PMOC | |||
| 1722 | Pass EL1:4 | ||
| 1978 Aug 13 | 1650? | Leave Earth sphere (L1) | |
| 1978 Aug 15 | 1750 | TCM-1 axial 2.2m/s | |
| 1919 | TCM-1 radial 1.3m/s | ||
| 1978 Oct 19 | TCM-2 | ||
| 1978 Nov 9 | 2215 | TCM-3 radial | |
| 1978 Nov 10 | 0305 TCM-3 axial | ||
| 1978 Nov 16 | 0237:13 | SP sep | |
| 1821 | Axial delta-V, targeting | ||
| 1978 Nov 20 | 1000 | Axal trim delta-V | |
| 1050 | Radial trim delta-V | ||
| 1306:29 | Small probes sep | ||
| 1978 Nov 22 | 0319 | Bus targeting delta-V axial | |
| 0516 | Turn to entry attitude | ||
| 1978 Dec 7 | 1700? | LP Enter Venus sphere | |
| 1700? | DP in sphere | ||
| 1710? | NoP in sphere | ||
| 1710? | NiP in sphere | ||
| 1978 Dec 7 | 1825? | Bus Enter Venus sphere | |
| 1978 Dec 8? | BNMS cap ejected 0.31kg | ||
| 1978 Dec 9 | 1137:12 | Trim burn, axial dV | |
| 1349 | Attitude trim | ||
| 1978 Dec 9 | 2021:52 | Entry at -9.4 deg | |
| 2022:55 | Burn up at 110 km | ||
Payload:
- BNMS Neutral mass spectrometer (Bonn/von Zahn)
- BIMS Ion mass spectrometer (GSFC/Taylor)
The large Sounder Probe separated from the Multiprobe Bus at 0237:13 on 1978 Nov 16. Range to Venus was 11 Mkm. The coast timer timed out at 1824:26 on Dec 9, and telemetry switched on at 1829:27. Atmospheric entry at an angle of -32.4 (-31.1 older value) deg and an altitude of 200 km at 11.537 km/s began over 5.7 deg latitude, 306.0 deg longitude at 1845:32. Blackout was from 1845:53 to 1846:55. At 1846 the drogue chute pulled off the probe aft cover. The parachute was deployed at 1846:21 and jettisoned at 1903:28. At around 1847 the Deceleration Module (heatshield) was jettisoned and the Descent Module was on its own. After a 54 min 21s descent, the probe impacted and fell silent at 1939:53 on 1978 Dec 9. The impact site was 4.0 deg latitude, 304.0 deg longitude.
| Sounder | |||
| Date | Time | Event | Orbit |
|---|---|---|---|
| 1978 Nov 16 | 0237:13 | Sep from PV2 | |
| Coast timer | |||
| 1978 Dec 9 | |||
| 1829:27 | Activated | ||
| 1845:32 | Entry 200 km | ||
| Mortar fire | |||
| Pilot deploy | |||
| 1846:21? | Aft cover+pilot sep, para deploy at 67 km | ||
| 1847 | Main deploy, aeroshell sep | ||
| 1847 | LNMS breakoff cap sep 66 km | ||
| 1903:28 | Para sep, 46 km, begin free fall | ||
| 1939:53 | Impact | ||
Payload:
- LNMS Neutral mass spectrometer (UTD/Hoffman)
- LGC Gas chromatograph (ARC/Oyama)
- LAS Comparative Atmospheric structure instrument (ARC/Seiff) Temperature, pressure, accelerometers
- LSFR Solar flux radiometer (Arizona/Tomasko)
- LIR IR radiometer (ARC/Boese)
- LCPS Cloud particle size spectrometer (PMSI/Knollenberg)
- LN Nephelometer (ARC/Paris/Ragent,Blamont)
The North Probe (Small Probe 1) separated from the Multiprobe Bus at 1306:29 on 1978 Nov 20.
Landing was on Dec 9. The coast timer timed out at 1827:57 and telemetry began at 1832:55. Entry was at 1849:40 at 200 km altitude, 59.7 deg lat, 5.0 deg longitude. The entry angle was -68.7 (-69.5 according to older sources) deg at 11.537 km/s. Blackout was from 1849:58 to 1850:55. The North Probe impacted on the surface of Venus at 60.1 deg latitude, 4.4 deg longitude and signals ceased immediately afterwards.
| NoP | |||
| Date | Time | Event | Orbit |
|---|---|---|---|
| 1978 Nov 20 | 1306:29 | Sep from Bus | |
| 1978 Dec 9 | 1832:55 | Telemetry on | |
| 1845:55 | Despin weights release? | ||
| 1849:40 | Entry at 200 km | ||
| 1849:58 | LOS | ||
| 1850:55 | AOS | ||
| 1942:40 | Impact | ||
The Day probe (Small Probe 2) separated from the Multiprobe Bus at 1306:29 on 1978 Nov 20. The coast timer timed out at 1830 on Dec 9, and telemetry was switched on at 1835:27. The probe entered the Venusian atmosphere at an altitude of 200 km at 1852:18. The location of the entry was 320.8 deg longitude, -30.6 deg latitude and the entry angle was -25.3 deg at 11.537km/s. Blackout lasted for 66 s from 1852:40 to 1853:46. Descent time was 55:41 with imact at 1947:59 at location 318.4 longitude, -32.4 latitude. The probe survived impact and transmitted until 2055:34.
| DP | |||
| Date | Time | Event | Orbit |
|---|---|---|---|
| 1978 Nov 20 | 1306:29 | Sep from Bus | |
| 1978 Dec 9 | 1835:27 | Telemetry on | |
| 1847:18 | Despin weights release? | ||
| 1852:18 | Entry at 200 km | ||
| 1852:40 | LOS | ||
| 1853:46 | AOS | ||
| 1947:59 | Impact | ||
| 2055:34 | End of data | ||
The Night Probe (Small Probe 3) separated from the Multiprobe Bus at 1306:29 on Nov 20. Range to Venus was 9.3 million km. Telemetry switched on at 1834:08 on 1978 Dec 9, and the 200 km altitude entry interface point was crossed at 1856:13, at -26.1 lat, 56.0 long. The entry angle was -41.5 deg at 11.537 km/s at 200 km. Blackout lasted from 1856:27 to 1857:48. and descent for 55m 52s. Entry orbit was -2220 x -32100 km x 68 deg. The Night Probe impacted on the surface of Venus at -27.4 lat, 56.7 long at 1952:05 on 1978 Dec 9. It stopped transmitting at most 2 seconds later, at 1952:07, but a later review suggested data ended at impact.
| NP | |||
| Date | Time | Event | Orbit |
|---|---|---|---|
| 1978 Nov 20 | 1306:29 | Sep from Bus | |
| 1978 Dec 9 | 1834:08 | Telemetry on | |
| 1851:13 | Despin weights release (48 rpm to 15 rpm) | ||
| 1856:13 | Entry at 200 km | ||
| 1856:27 | LOS | ||
| 1857:48 | AOS | ||
| Nephelometer window open | |||
| ASI and NFR housing doors open | |||
| 1952:05 | Impact | ||
