Pioneer Venus Multiprobe
National Affiliation: USA
Launch Date/Time: 1978-08-08 at 07:33:00 UTC
Launch Vehicle: Atlas-Centaur
Pioneer Venus Probe Bus
Other Name(s)
- Pioneer 13
- Pioneer Venus 1978
- Pioneer Venus 2
- 11001
On-orbit dry mass: 380.00 kg
Description
The spacecraft was the Bus portion of the Pioneer Venus Multiprobe
mission. On this mission four instrumented atmospheric entry Probes
were carried by this Bus to the vicinity of Venus and released for
descent through the atmosphere to the planetary surface. Two Small
Probes entered on the nightside, and one Small Probe and the Large
Probe entered on the dayside of the planet. The spacecraft was
spin-stabilized. The trip to Venus took 123 days. The four Probes
separated from the Bus about 10 to 20 days before entry. The Large
Probe took 1-1/2 h to descend through the atmosphere, while the three
smaller probes reached the surface of the planet 75 min after entry.
The Bus portion of the spacecraft was targeted to enter the Venusian
atmosphere at a shallow entry angle and transmit data to earth until
the Bus was destroyed by the heat of atmospheric friction during its
descent. Investigators emphasized the study of the structure and
composition of the atmosphere down to the surface, the nature and
composition of the clouds, the radiation field and energy exchange in
the lower atmosphere, and local information on the atmospheric
circulation pattern. A sister mission, Pioneer Venus Orbiter, placed
an orbiting spacecraft around Venus two weeks before the Probes were
released. Simultaneous measurements by the probes and orbiter
permitted relating specific local measurements to the general state of
the planet and its environment as observed from orbit. The Probes
stopped transmitting temperature data about 15 km above the surface of
Venus, but two Probes survived on the surface and transmitted other
data for a matter of seconds to minutes. The Bus ceased transmitting
data at an altitude of about 165 km.
Pioneer Venus Large Probe
Other Name(s)
- Pioneer Venus 1978
- Pioneer Venus Probe Large
On-orbit dry mass: 300.00 kg
Description
This spacecraft was the Large Probe portion of the Pioneer Venus
Multiprobe mission. On this mission four instrumented atmospheric
entry probes were carried by a spacecraft bus to the vicinity of Venus
and released for descent through the atmosphere to the planetary
surface. Two Small Probes entered on the nightside and a Small Probe
and this Large Probe entered on the dayside of the planet. The
spacecraft Bus entered the atmosphere and obtained atmospheric
composition data until burnup. Investigations emphasized the study of
the structure and composition of the atmosphere down to the surface,
the nature and composition of the clouds, the radiation field and
energy exchange in the lower atmosphere, and local information on the
atmospheric circulation pattern. A sister mission, Pioneer Venus
Orbiter, placed an orbiting spacecraft around Venus two weeks before
the Probes were released. Simultaneous measurements by the Probes and
Orbiter permitted relating specific local measurements to the general
state of the planet and its environment as observed from orbit.
Pioneer Venus Small Probe (North)
Other Name(s)
- Pioneer Venus 1978
- Pioneer Venus North Probe
- Pioneer Venus Probe North
On-orbit dry mass: 75.00 kg
Description
This spacecraft was the first Small Probe of the Pioneer Venus
Multiprobe mission. On this mission four instrumented atmospheric
entry probes were carried by a spacecraft Bus to the vicinity of Venus
for descent through the atmosphere to the planetary surface. Two
Small Probes entered on the nightside, and one Small Probe and one
Large Probe entered on the dayside of the planet. The spacecraft Bus
entered the atmosphere and obtained atmospheric composition data until
burnup. Investigations emphasized the study of the structure
composition and nature of the atmosphere down to the surface, and of
the clouds, the radiation field and energy exchange in the lower
atmosphere, and local information on the atmospheric circulation
pattern. A sister mission, Pioneer Venus Orbiter, placed an orbiting
spacecraft around Venus two weeks before the probes were released.
Simultaneous measurements by the Probes and Orbiter permitted relating
specific local measurements to the general state of the planet and its
environment as observed from orbit.
Pioneer Venus Small Probe (Night)
Other Name(s)
- Pioneer Venus 1978
- Pioneer Venus Night Probe
- Pioneer Venus Probe Night
On-orbit dry mass: 75.00 kg
Description
This spacecraft was the second Small Probe of the Pioneer Venus
Multiprobe mission. On this mission four instrumented atmospheric
entry probes were carried by a spacecraft Bus to the vicinity of Venus
for descent through the atmosphere to the planetary surface. Two
Small Probes entered on the nightside, and one Small Probe and one
Large Probe entered on the dayside of the planet. The spacecraft Bus
entered the atmosphere and obtained atmospheric composition data until
burnup. Investigations emphasized the study of the structure
composition and nature of the atmosphere down to the surface, and of
the clouds, the radiation field and energy exchange in the lower
atmosphere, and local information on the atmospheric circulation
pattern. A sister mission, Pioneer Venus Orbiter, placed an orbiting
spacecraft around Venus two weeks before the Probes were released.
Simultaneous measurements by the Probes and Orbiter permitted relating
specific local measurements to the general state of the planet and its
environment as observed from orbit.
Pioneer Venus Small Probe (Day)
Other Name(s)
- Pioneer Venus 1978
- Pioneer Venus Day Probe
- Pioneer Venus Probe Day
On-orbit dry mass: 75.00 kg
Description
This spacecraft was the third Small Probe of the Pioneer Venus
Multiprobe mission. On this mission four instrumented atmospheric
entry Probes were carried by a spacecraft Bus to the vicinity of Venus
for descent through the atmosphere to the planetary surface. Two
Small Probes entered on the nightside, and one Small Probe and one
Large Probe entered on the dayside of the planet. The spacecraft Bus
entered the atmosphere and obtained atmospheric composition data until
burnup. Investigations emphasize the study of the structural
composition and nature of the atmosphere down to the surface, and of
the clouds, the radiation field and energy exchange in the lower
atmosphere; and local information on the atmospheric circulation
pattern. A sister mission, Pioneer Venus Orbiter, placed an orbiting
spacecraft around Venus two weeks before the Probes were released.
Simultaneous measurements by the Probes and the Orbiter permitted
relating specific local measurements to the general state of the
planet and its environment as observed from orbit.
Pioneer Venus Probes and Bus - Atmospheric Entry
All times in UT (= EST + 5 hours) on December 9, 1978
Large Probe North Probe Day Probe Night Probe Bus
Entry Time (200 km) 18:45:32 18:49:40 18:52:18 18:56:13 20:21:52
Impact Time 19:39:53 19:42:40 19:47:59 19:52:05 *
Loss of Signal 19:39:53 19:42:40 20:55:34 19:52:07 20:22:55
Impact Latitude 4.4 N 59.3 N 31.3 S 28.7 S (37.9 S)
Impact Longitude 304.0 4.8 317.0 56.7 (290.9)
Solar Zenith Angle 65.7 108.0 79.9 150.7 60.7
Local Venus Time 7:38 3:35 6:46 0:07 8:30
*Bus signal lost at 110 km altitude
Other Pioneer Venus Multiprobe Images
