 |
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| THE EXPLORATION OF VENUS |
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| In spite of its inhospitable atmosphere, Venus has been
explored by a large number of space missions, with the Soviet Union taking
the lead during the 1970s and 80s. |
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| The first spacecraft to return useful data about Venus
was Mariner 2. Mariner 2�s closest approach to Venus was 34,800 kilometres
on 14 December 1962. Readings from Mariner 2�s instrumentation showed
Venus�s surface to be around 800 degrees Fahrenheit (425� C). Mariner
2 transmitted data for three weeks and is now in orbit around the Sun. |
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| On 12 February 1961, the Russians launched the first of
the 16 Venera missions. |
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| Arriving at Venus on October 18, 1967, Venera 4 was the
first probe to enter Venus�s atmosphere and return data. This showed that
the atmosphere was over 90% carbon dioxide. A surface temperature of 500�
C was measured. The spacecraft was crushed by the 75 bar pressure before
it could reach the surface. |
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| 3 years later, on 15 December 1970, Russia succeeded in
landing the first spacecraft on Venus. Venera 7 was also the first landing
achieved on another planet. Venera 7 had an external cooling device that
allowed it to send back data for 23 minutes before it was destroyed by
the 90 bar pressure and the surface temperature of 475� C |
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| The successful Venera program continued with Venera 8 in
July 1972. Venera 8 measured the wind speed as it descended through the
atmosphere, detecting a huge difference between 100 metres/second winds
above 48 kilometres, reducing to 1 meter/second below 10 kilometres. Venera
8 transmitted data for 50 minutes after landing. |
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| Mariner 10 flew past Venus on February 5, 1974 en-route
for Mercury. Mariner 10 showed temperatures of -23�C in the upper cloud
layer. |
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| Venera 9 and Venera 10 arrived at Venus on 22 October 1975
and 25 October 1975 respectively. Both orbiters photographed the cloud
layer. Venera 9 sent a lander was to the surface, that arrived there on
22 November 1975. For 53 minutes, the Venera 9 lander transmitted the
first images of the Venusian surface showing flat rocks covering a terrain
formed by volcanic activity. The Venera 10 lander arrived on the surface
3 days later and transmitted black and white images for a period of 65
minutes. |
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| The US Pioneer Venus mission also employed two spacecraft
(Pioneer Venus 1 and Pioneer Venus 2), in this case arriving at Venus
5 days apart (on 4 and 9 December 1978). Pioneer Venus 1 made the first
use of radar to map the planet�s surface. Pioneer Venus 1 orbiter operated
continuously for nearly 14 years. Over this long period the instruments
detected significant changes in the Venusian atmosphere with the quantity
of sulphur dioxide decreasing by 10%. |
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| Pioneer Venus 2 carried four probes. These probes transmitted
data as they descended through the atmosphere, slowed by parachutes. Interestingly,
once below the dense cloud layer, they recorded a clear atmosphere at
30 kilometres above the surface |
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| The two Russian Vega missions flew past Venus, in June
and July 1985, on their way to an encounter with Halley�s comet. Vega
2 successfully dropped off a lander that performed experiments on soil
samples. These showed that the soil contained chemicals also found in
the Lunar highlands. |
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| The most comprehensive information we have about what
Venus looks like below its cloud layer, comes from the Magellan spacecraft.
Between 10 August 1990 and 1994 Magellan systematically mapped the surface
of Venus using synthetic aperture radar. Data collected by Magellan has
been used to produced a surface map with a resolution of 300 metres. |
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| Spacecraft |
Launch date |
Arrival date |
Mission
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| Venera 1 |
12 Feb 1961 |
19 May 1961 |
Venus Flyby (Contact Lost)
|
| Mariner 2 |
27 Aug 1962 |
14 Dec 1962 |
Venus Flyby |
| Venera 2 |
12 Nov 1965 |
27 Feb 1966 |
Venus Flyby (Contact Lost)
|
| Venera 3 |
16 Nov 1965 |
1 Mar 1966 |
Venus Lander (Contact Lost)
|
| Venera 4 |
12 Jun 1967 |
18 Oct 1967 |
Venus Probe |
| Mariner 5 |
14 Jun 1967 |
19 Oct 1967 |
Venus Flyby |
| Venera 5 |
5 Jan 1969 |
16 May 1969 |
Venus Probe
|
| Venera 6 |
10 Jan 1969 |
17 May 1969 |
Venus Probe |
| Venera 7 |
17 Aug 1970 |
15 Dec 1970 |
Venus Lander |
| Venera 8 |
27 Mar 1972 |
22 Jul 1972 |
Venus Probe |
| Mariner 10 |
4 Nov 1973 |
5 Feb 1974 |
Venus/Mercury Flybys |
| Venera 9 |
8 Jun 1975 |
23 Oct 1975 |
Venus Orbiter and Lander
|
| Venera 10 |
14 June 1975 |
26 Oct 1975 |
Venus Orbiter and Lander
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| Pioneer Venus 1 |
20 May 1978 |
4 Dec 1978 |
Venus Orbiter |
| Pioneer Venus 2 |
8 Aug 1978 |
9 Dec 1978 |
Venus 5 Probes |
| Venera 11 |
9 Sep 1978 |
21 Dec 1978 |
Venus Orbiter and Lander
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| Venera 12 |
14 Sep 1978 |
25 Dec 1978 |
Venus Orbiter and Lander
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| Venera 13 |
30 Oct 1981 |
|
Venus Orbiter and Lander
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| Venera 14 |
4 Nov 1981 |
1 Mar 1982 |
Venus Orbiter and Lander
|
| Venera 15 |
2 Jun 1983 |
10 Oct 1983 |
Venus Orbiter |
| Venera 16 |
7 June 1983 |
14 Oct 1983 |
Venus Orbiter |
| Vega 1 |
15 Dec 1984 |
11 Jun 1985 |
Venus Lander and balloon
|
| Vega 2 |
21 Dec 1984
|
15 Jun 1985
|
Venus Lander
and balloon |
| Magellan |
4 May 1989 |
10 Aug 1990 |
Venus Orbiter |
|
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| Future Missions |
| The Japanese Space Agency (ISAS) has plans for a Venus
orbiter named 'Planet-C', which they hope to launch in 2007. The official
approved project, would make a flyby of Earth in 2008 and arrive at Venus
in 2008. The spacecraft will carry a suite of science instruments including
cameras able to return infrared and ultraviolet wavelength images. The
main objectives of the mission are to study Venus' weather and look for
ongoing volcanic activity on the planet. |
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