A series of Soviet probes designed to fly by, orbit, and land on Venus.
The Venera spacecraft, unlike the Soviet Mars
probes, were tremendously successful, and made the first soft landings on
and sent back the first pictures from the surface of Venus.
The first spacecraft to fly past Venus; however, all contact with the probe
was lost just seven days after launch, when it was about 2 million km from
Earth. After its remote Venusian rendezvous, Venera 1 went into orbit
around the Sun. Note: the first successful Venus probe was Mariner 2.
Like its predecessor, a flyby mission that suffered a communications breakdown
long before its arrival at the second planet. Note: the first spacecraft
in the Zond series was actually the second Soviet probe launched
toward Venus and it too was lost.
The first attempted landing on Venus. The entry vehicle carried science
instruments and medallions bearing the Soviet emblem. However, communication
with the probe was lost during descent through the crushing Venusian atmosphere.
The first probe successfully to send back information during its parachute
descent through the atmosphere of Venus.
Venera 5 and 6
Twin spacecraft similar to Venera 4 but of stronger design. Each deployed
a 405-kg descent probe that sent back information about the atmosphere for
about 50 minutes. Each also carried a medallion bearing the Soviet emblem
and a bas relief of Lenin to the night side of Venus but failed to transmit
from the surface.
The first probe to return data after landing on another planet. Following
aerodynamic braking and deployment of its parachute system, Venera 7
extended its antenna and transmitted for 35 minutes during its descent and
a further 23 minutes of very weak signals from the surface.
The second successful Venus lander. Venera 8 slowed from 41,696 km/hr
to about 900 km/hr by aerobraking, then opened its 2.5-m-diameter parachute
at an altitude of 60 km, and transmitted data during its descent. A refrigeration
system cooled the interior components and enabled signals to be sent back
for 50 minutes after landing. The probe confirmed Venera 7's data
on the high surface temperature and pressure, and also determined that the
light level was suitable for surface photography, being similar to the illumination
on an overcast day on Earth.
Venera 9 and 10
A pair of identical spacecraft, each consisting of an orbiter and a lander.
After separation of the lander, the orbiter spacecraft entered orbit around
Venus, studied the upper clouds and atmosphere, and served as a communications
relay for the lander. Each lander was slowed down sequentially by protective
hemispheric shells, three parachutes, a disk-shaped drag brake, and a compressible,
metal, doughnut-shaped, landing cushion. Each sent back data from the surface
for 53 minutes and 65 minutes, respectively, from locations about 2,200
km apart and became the first probes to transmit black and white pictures
from the Venusian surface. Full 360° shots were not returned, however,
because on each probe one of two camera covers failed to come off, restricting
the field of view to a half-circle.
Venera 11 and 12
A two-spacecraft mission, each craft consisting of a flight platform and
a lander. After ejection of their landers, the flight platforms flew past
Venus, serving as data relays for over an hour and a half until they traveled
out of range to continue their investigations of interplanetary space. The
Venera 12 flyby bus successfully used its Soviet-French ultraviolet
spectrometer to observe Comet Bradfield in February 1980. Both Venera
11 and 12 landers failed to return color TV views of the surface
and perform soil analysis experiments as planned. All of the camera protective
covers failed to eject after landing and the soil drilling experiments were
damaged by exposure to the high Venusian atmospheric pressure. Results reported
included evidence of lightning and thunder, and the discovery of carbon
monoxide at low altitudes.
Venera 13 and 14
Identical orbiter/landers launched within the same week. The landing probes
touched down 950 km apart to the northeast and east, respectively, of an
elevated basaltic plain known as Phoebe Regio. Venera 13 became the
first spacecraft to remotely analyze the Venusian surface. Its mechanical
drilling arm obtained a sample, which was deposited in a hermetically sealed
chamber and maintained at 30°C and a pressure of about 0.05 atmospheres.
The makeup of the sample, as determined by the X-ray fluorescence spectrometer,
appeared similar to that of oceanic basalts on Earth. Venera 14's
attempt at surface analysis was foiled when its drilling arm landed on one
of the ejected camera covers.
Venera 15 and 16
A two-spacecraft mission that used side-looking radar mappers to study the
surface properties of Venus. The two probes entered nearly polar orbits
around Venus a day apart with their orbital planes inclined about 4°
apart. This made it possible to reimage an area if necessary. Over their
eights months of operation, the spacecraft mapped the area from the north
pole down to about 30° N latitude.