Translated material
Planet of dry clouds
Water from Venus was blown away by the solar wind
One of the most mysterious planets in the solar system is gradually losing its atmosphere. Experts from the European Space Agency have received confirmation that solar wind streams are gradually blowing the famous clouds of Venus into outer space. This information came from the Venus Express automatic station, which studied the planet closest to us for a year and a half. The first results of this project were announced on November 28 in Paris.The solar wind is a stream of charged particles that our star ejects into space. We are lucky on Earth: most of the life-threatening radiation is slowed down or deflected to the sides by the planet's magnetic field. But Venus, oddly enough, has practically no magnetic field of its own, and therefore the solar wind reaches the atmosphere unhindered. These particles ionize the gas and “kick it out” into space. First of all, water vapor “suffers”, of which there is very little in the Venusian air. The molecules disintegrate, and hydrogen and oxygen leave the atmosphere.
However, this wind is not able to “blow away” the super-dense clouds enveloping the Morning Star. Venus is surrounded by a thick layer of very dense and low-transparent atmosphere, which consists mainly of carbon dioxide. Nevertheless, solar radiation copes quite successfully with water vapor. Scientists even suggest that it was this wind of charged particles that turned the planet closest to us into an almost waterless celestial body.
In size, the second planet of the solar system is very similar to the Earth, but if we have water almost everywhere, then the surface of Venus is a dry, hot, lifeless desert. Perhaps in the early stages of evolution there was more water here - of course, not sea, but most likely clouds of water vapor. Then Venus could be somewhat reminiscent of the Earth, only hotter. But now the second planet is shrouded in a toxic atmosphere, and although it is called Earth’s twin, only its size remains similar.
True, at the same time, on Venus there is, for example, such a familiar weather phenomenon as lightning. Their presence had been predicted earlier, but only the Venus Express equipment was able to calculate their approximate number. In high latitudes, near the poles, lightning is very frequent, and, as researchers suggest, at least 50 electrical discharges jump between the atmosphere and the surface of the planet every second (by the way, on Earth there are still twice as many lightning strikes). Lightning appears to contribute to the formation of the Venusian atmosphere: atmospheric electricity ionizes local air and can lead to the formation of complex molecules such as nitric acid.
The remaining discoveries of Venus Express look less sensational. The station primarily studied Venusian weather, in comparison with which the most powerful terrestrial storm looks completely calm. For example, there are giant vortices near the poles; they are similar to those cyclones and anticyclones that form on Earth. But the storms of Venus are much more powerful, their speed reaches 360 km per hour. True, such gusts were recorded by the orbital station’s equipment only in the dense cloud layer of the atmosphere, at an altitude of 60 km from the surface. Below, under this blanket, lies a layer of air heated to 465 degrees Celsius and, oddly enough, almost windless. Scientists believe that the wind there is not even capable of raising dust.
Second European "Express"
“Venus Express” is the second serious project of the European Space Agency (ESA) to study the terrestrial planets closest to us. The first in the series was Mars Express, which set off for the Red Planet in June 2003. This station was supposed to observe the surface and atmosphere of Mars from orbit for several years, which is what it is doing to this day. But the Beagle-2 landing module was unable to complete the task: it is generally accepted that it crashed during landing.
For the flight to Venus, ESA decided to use the Martian experience. Only they refused to send a probe to the surface of the planet: “Venus Express” is only an orbital vehicle. The refusal to land on the surface, as well as the fact that some instruments developed for the Mars mission were also used in the study of the second planet, sharply reduced the cost of the project. The Venus Express cost 235 million euros, the flight to Mars cost about 300 million.
The Venus Express station was launched in November 2005 from Baikonur, carried into space by the domestic Soyuz-Fregat launch vehicle. The device reached Venus in April of the following year, after which it slowed down and entered a highly elongated elliptical orbit. It either approached the planet almost closely - at a distance of 250 km, or moved away to 66 thousand km. At first it was assumed that the device would operate in orbit for 500 days, but already this year the service life of the orbital station was extended until 2009. Nevertheless, Venus Express has already completed its main task - studying the atmosphere and solar wind - and now ESA hopes that the station will be able to study the work of Venusian volcanoes.
Flights to the Morning Star
Since Venus is the closest celestial body to Earth (except for the Moon), they began to fly to it at the very beginning of the space age. The USSR sent the first mission to this planet even before Gagarin’s flight, but Venera-1, launched at the very beginning of 1961, did not complete the task (communication with the station was lost halfway). The Americans were luckier: in 1962 they sent Mariner 2 to Venus. The device approached the planet by 35 thousand km. With its help, scientists were able to “see” the dense clouds surrounding the planet, and also find out that the surface of this celestial body is heated to a high temperature. It was also discovered that Venus has virtually no magnetic field.
After Mariner 2, the Americans did not fly to Venus for some time, and the USSR persistently sought to repeat and surpass the success of its overseas competitors. But what happened with the domestic Venus research program in the 60s of the last century can easily cause superstitious people to suspect that these launches were cursed by someone very powerful. Missile after missile was sent from Baikonur, but the automatic stations broke down before reaching the target. The first truly successful flight to the second planet took place only in 1967, when Venera 4 passed through the dense layers of the atmosphere and analyzed their composition.
From that moment on, the Soviet era began in the study of the clouds of Venus, which lasted almost twenty years. If NASA eventually began to specialize in flights to distant planets, then our space program, as usual, sent station after station to the Earth’s closest neighbor. From 1962 until the early 90s, the United States launched only four missions to Venus. In 1974, Mariner 10, flying to Mercury, passed by the second planet, and in 1978, the Americans sent two automatic stations, Pioneer Venus. They worked in Venusian orbit until 1992.
Our devices were not designed for such a long life, but the Venus series was launched until 1983. The latest stations - "Venera-15" and "Venera-16" - carried out radar surveys of the northern polar regions of the planet's surface, which made it possible to create fairly detailed maps. But in addition to the remote study of Venus, the Soviet program involved studying the surface using landers (Venera 7 was the first to break through the cloud layer and successfully land in 1970). And in 1984-1986, perhaps the most difficult launch in the history of the Russian interplanetary flight program was carried out. We are talking about “Vega-1” and “Vega-2”.
Both stations had a dual goal: they had to first get to Venus, and then move on to Halley's comet, which in 1986 once again approached the Sun. But only small probes were sent to the tailed star, while Vega dropped two devices at once, literally packed with various instruments. One of them was supposed to make a soft landing, while the other was a small balloon filled with helium. These probes drifted for some time at an altitude of fifty kilometers above the surface, collecting information about the atmosphere. No one has sent such unusual devices to other planets before.
"Vegas" became both the pinnacle of the Soviet Venusian program and its end. After the collapse of the USSR, Russia was no longer interested in interplanetary flights. The last major project to explore Venus was carried out by the United States: in the first half of the 90s, the Magellan station operated in orbit of the second planet, using its radars to make the most accurate and detailed map of the planet’s surface. Then Venus, scanned length and breadth, was practically forgotten, and more distant celestial bodies became the targets of research missions of NASA and the European Space Agency. Launched in 2005, Venus Express became the first expedition of the 21st century to go to the second planet.