The planet Venus
is named after the Roman goddess of love and beauty. An orbital average of
108,208,930 kilometers places it second closest to the Sun
in order of distance, while a diameter of 12,104 kilometers places it
sixth in the Solar System in order of
Comparisons between Earth
and our closest neighbor are inevitable, after all the two planets are
roughly the same size and mass but here real similarities end. Venus
has no moon and unlike Earth is completely enshrouded in cloud. Early
preconceptions took this to mean that Venus was a wet planet perhaps
similar to Earth during its Jurassic period, humid, warm, damp and
covered in lush jungle. Nothing could have been further from the truth.
has been revealed to be an exceptionally uninviting place. Atmospheric
pressure at the surface is equivalent to that found at a depth of 1
kilometer in Earth's oceans. The atmosphere itself is mainly carbon
dioxide (96.5%) and the clouds are opaque, highly reflective and
composed of sulphuric acid. This combined with a mean surface
temperature of 462 °Celsius, hot enough to melt lead, makes the
likelihood of finding life of any kind slim indeed.
Venus has been the target of more terrestrial spacecraft than any other
planet in the Solar System other than Mars:
Mariner 1, the first spacecraft of the Mariner program and intended for
a Venus flyby, was aborted after veering off course shortly after
take-off July 22, 1962.
Mariner 2 holds the title for first
successful interplanetary mission, passing 34,833 km above the Venusian
surface December 14, 1962.
Mariner 5, originaly intended as a
backup for the Mariner 4 Mars mission, was refitted for Venus. Launched
from Cape Canaveral on June 14, 1967, it passed by our sister planet at
an altitude of 3,990 km (2,480 miles) on October 19, 1967, shedding new
light on Venus, its atmosphere and magnetic field along with conditions
in interplanetary space.
Mariner 10 launched on November 3, 1973, passed Venus on its way to Mercury
February 5, 1974, closest approach during its flyby 5,768 km. Following
three flybys of the Solar System's innermost planet, its transmitter
shut down, its electronics probably damaged by solar radiation it still
orbits the Sun cold and silent.
The Pioneer Venus project
consisted of two different missions. The Venus Orbiter entered orbit
around Venus on December 4, 1978, and for the next 13 years studied the
atmosphere and mapped the surface. The Venus Multiprobe (four probes)
entered the Venusian atmosphere on December 9, 1978, sending back data
on the atmosphere and clouds before being destroyed by friction.
launched May 4, 1989, used radar imaging to compile detailed maps of
Venus from orbit before descending (intentionally) into the Venusian
atmosphere at mission's end.
Messenger made two flybys of Venus
in 2006 and 2007, using the planet to slow its trajectory prior to an
orbital insertion of Mercury in 2011.
Galileo used Venus for a gravity assist on February 10,1990, on its way
(NASA/ESA/ASI) Cassini-Huygens used Venus for a gravity assist on April
26, 1998, and June 24, 1999, on its way to Saturn.
The European Space Agency's Venus Express, presently in orbit, is
engaged in studying Venus' atmosphere, clouds and surface
(USSR) Sputnik 7, 19, 20, 21, all failed/lost early 1960s.
Cosmos 21, 27, 96, 167, 359, 482, all failed/lost 1960s early 1970s.
Venera 1 did in fact flyby Venus (the first spacecraft to do so) May
19,1961, but contact had been lost 7 days after launch.
Zond 1 was the second Soviet probe to reach Venus July 14, 1964, but
contact had been lost en route.
Venera 1964a and 1964b failed to reach Earth orbit early 1960s.
Venera 1965a failed.
Venera 2 ceased to operate while en route.
3 probably crashed while attempting a landing March 1, 1966, but
confirmation was impossible because of communication failure.
Venera 4 entered the Venusian atmosphere on October 18, 1967, and
continued to transmit data to an altitude of 25 kilometers.
Venera 5 entered the Venusian atmosphere on May 16, 1969, transmitting
data for 53 minutes to an altitude of 26 km.
Venera 6 entered the Venusian atmosphere on May 17, 1969, transmitting
data for 51 minutes to an altitude of 10 to 12 km.
7 entered the Venusian atmosphere on December 15, 1970, landing hard
shortly thereafter (the first terrestrial craft to touch down on
another planet) a weak 23 minute signal returning temperature readings
of 475 degrees Celsius (887 °F).
Venera 8 entered the Venusian
atmosphere on July 22, 1972, transmitting data until landing in what is
now called the Vasilisa Region. Transmission continued for another 50
minutes 11 seconds.
Venera 9 entered the orbit of Venus on
October 22, 1975. Consisting of an orbiter (the first spacecraft to
orbit the planet) and lander (the first to return images [black and
white] from the surface of another planet).
Venera 10 entered
the orbit of Venus on October 25, 1975, as with Venera 9 it consisted
of an orbiter and a lander (the second to send back black and white
images from the surface of another planet.
Venera 11's lander
entered the Venusian atmosphere on December 25, 1978, landing softly
shortly thereafter. Instruments on board (some of which failed) studied
atmospheric temperatures and composition. The flight platform relayed
the data for 95 minutes before eventualy moving out of range.
Venera 12 mission almost identical to Venera 11.
13 consisted of a cruise stage and a descent vehicle. On March 1, 1982,
after seperating, the descent vehicle plunged into the Venusian
atmosphere landing safely shortly thereafter. The lander survived for
127 minutes, taking samples of the surface and colour images of its
surroundings the data transmitted to the cruise stage which acted as a
relay as it passed by the planet.
Venera 14 mission almost identical to Venus 13.
15 and 16 were identical in both construct and mission. They were
inserted into a nearly polar orbit a day apart (Venera 15 on October
10, 1983, Venera 16 on October 11, 1983). Together they imaged about
25% of the Venusian surface over an 8 month period.
Vega 1 and
Vega 2 were identical spacecraft designed for a dual mission, to visit
both Venus and Halley's Comet which was passing through the inner Solar
System. On June 11 and June 15, 1985, the two craft each dropped a
Venera-style probe (Vega 1's deployed prematurely) along with a balloon
supported aerial robot into Venus' upper atmosphere. The balloons
achieved equilibrium at an altitude of around 53 kilometers and
remained operational for around 46 hours travelling thousands of
kilometers. The two flyby spacecraft using a gravitational assist
courtesy Venus continued on to Halley's Comet.
(Planet-C) a spacecraft originally slated to rendevous with Venus
December 2010 achieved, after failing the first time, success with
a second try in 2015. If further success follows the probe will continue
with its mission,
complementing ESA's Venus Express, its job detect and observe such
things as lightning, airglow and volcanic activity along with studying
the atmosphere and gaining a better understanding of the mechanisms
that control atmospheric circulation. 
 Launched together
with AKATSUKI was IKAROS (Interplanetary Kite-craft Accelerated by
Radiation Of The Sun) a solar-sail experiment, its mission to ascertain
whether a spacecraft can fly solely by solar powered sail and that thin
film solar cells can generate power, and Shin'en (UNISEC) a Japanese
student spacecraft which was intended to make a Venus flyby six or
seven months out. On December 8, 2010, IKAROS flew past Venus at about
50,200 miles (80,800 km) completing its mission before entering its
extended operation phase. Shin'en suffered comunication failure and was
lost shortly after launch.
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