When you read about the discoveries of the last century, it seems that all the most interesting has already been found and studied, and contemporaries have only reverence for the scientific power of the past century. However, this is not the case. Progress, technical and scientific, allows humanity to set more and more ambitious goals and achieve them. Among these can be attributed to the study of comets with the help of devices that can sink to their surface. It was for such purposes that the Rosetta probe was created, a spacecraft that went to the comet Churyumov-Gerasimenko in 2004. About him and will be discussed below.
A bit of history
The Rosetta mission is not the only attempt to investigate comets. The story begins back in the 1980s, when Vega and ICE, Soviet and American-European vehicles flew past tailed space bodies, received and transmitted certain information about them. These and subsequent meetings with comets brought scientists a lot of data. In particular, the core of such a cosmic body was photographed , a blank of metal was thrown onto a comet and after a few years they watched the results of the fall, dust samples from the comet's tail were delivered to Earth. However, the Rosetta probe has no analogues in the history of astronautics. Initially, a more complex task was set for him: to become for some time the comet’s satellite and lower the Fila apparatus to its surface for direct investigation of the object.
Landmark change
Initially, the comet Virtanen was supposed to be this very object. The choice was based on a convenient trajectory of the space body and some of its features, which reduced the risk of failure of the probe's research mission. In order to go to the comet Virtanen, the Rosetta satellite was supposed to launch in January 2003. However, about a month before, during the launch, the Arian-5 launch vehicle engine failed. As a result, it was decided to postpone the start of the probe and revise the flight program.
67P
The new object, which was supposed to send the Rosetta space probe, was comet 67P, it is also called Churyumova-Gerasimenko. It was opened in 1969 by Klim Churyumov in pictures taken by Svetlana Gerasimenko. The object is a short-period comet: every 6.6 years it flies near the Sun. The flight path is practically limited to the orbit of Jupiter. An important feature of this comet for researchers is the predictability of its flight, which means the ability to accurately calculate the necessary motion of the spacecraft.
Structure
The Rosetta probe carries a large amount of equipment, and the Fila descent module is not its only valuable part. Among the equipment is an ultraviolet spectrometer, which is necessary for analyzing gases in the tail of a comet and determining the composition of its nucleus, cameras operating not only in the visible, but also in the ultraviolet and infrared ranges, various equipment for studying the composition, temperature and speed of particles in the tail of an object, as well as determining its orbit, gravity and other characteristics. All this equipment is necessary both for obtaining data on the comet, and for finding the optimal landing site for the Fila apparatus.
Rosetta probe: flight path
Before reaching the goal, the apparatus for ten years traveled the expanses of the solar system. Such a large time period is explained by the need to approach the comet “from the rear”, to equalize speeds and move along a similar trajectory. In ten years, the Rosetta satellite flew past our planet five times. He managed to meet with Mars and several times cross the main belt of asteroids.
For ten years, the Rosetta space probe has sent colorful images of various objects to the Earth. In addition to aesthetic pleasure, they carry scientific information. Scientists have received new images of the surface of Mars, which made the probe "Rosetta", a photo of the asteroids Steins and Lutetia.
Of course, the apparatus and the Earth did not disregard. Pictures of the Rosetta probe demonstrate our planet from various angles, as well as some atmospheric phenomena.
Rapprochement
Throughout the flight, the Rosetta probe was lucky. At some point, to save resources, he was immersed in hibernation, where he spent a record 957 days. In January 2004, the Rosetta mission continued safely after awakening the satellite. However, the most difficult awaited him ahead. The greatest difficulties could arise during the landing of the Fila module, which delivered the Rosetta probe to the comet. The visualization of this moment, prepared by the European Space Agency, showed a soft landing of the device, accompanied by the release of three harpoons. They were necessary for fixing on the surface of the comet, the gravitational forces of which are such that the slightest push could lead to the disappearance of the Fila apparatus in outer space.
The rapprochement as a whole was successful, but it was not possible to release all three harpoons. The Fila module bounced off the surface twice during landing and only managed to land on the third, while remaining unsecured. The result of this incident was the removal of the device from the proposed landing site for about a kilometer, and the project participants could not accurately determine the point where the Fila device sat. Only an approximate landing area was clear.
57 hours
Landing problems caused the Fila module to hit a nearly permanently shaded surface. The main source of energy of the device is solar panels, which cannot work at temperatures below zero. As a result, most of the energy was spent heating up the batteries, but the amount of available sunlight was still small. The Fila apparatus was equipped for such situations with a charged battery lasting 64 hours. He worked, however, only 57. During this time, the Fila heroic module, whose exact location was not even determined, transmitted a lot of information about the comet to Earth , even (presumably) was able to drill the surface and take a soil sample.
All this time, Rosetta constantly monitored the actions of the Fila apparatus, and transmitted messages to and from it. Upon completion of the module, the probe began its own research activities.
The form
At the end of January 2015, several scientific articles were published containing a description of the research results. One of the interesting issues discussed in them is the unusual form of the comet. The cosmic body is similar to a rubber duckling: visually you can highlight the head, trunk and neck. The study of the data has not yet answered the question of whether the comet 67P arose as a result of a collision of two space objects, or its shape is a consequence of mass loss and severe erosion. In the first case, an event that supposedly occurred at the dawn of the solar system, 4.5 billion years ago, can be proved if fundamental differences between the two halves of the comet are discovered. The affirmation of the second hypothesis will make it necessary to find an answer to the question about the nature of the forces leading to such a strong erosion in the area of the “duckling neck”.
It is now known for sure that the comet inside has a porous structure. According to scientists, the density of the core is less than the same parameter of water by half.
Relief
The Rosetta probe and the Fila apparatus transmitted a mass of 67P surface images to Earth. Dunes and mountains, as well as gorges, were discovered on it. However, the cliffs of the comet only remotely resemble terrestrial ones. Some of them are basically compacted dust, many are the result of the circulation of gas and dust, that is, they are closer to desert dunes than to rocks.
Part of the hills, which rise three meters above the surface, were called goose bumps and are considered a formation characteristic of many similar cosmic bodies. Presumably, they formed during the period when the solar system was just beginning to form, and consist of adhering dust and ice.
Origin
Research apparatuses related to the water content and carbon compounds. Vibrations of the content of these substances were found to coincide with the rotation of the cosmic body around the axis and with the change of seasons. In addition, it turned out that 67P in its composition has a large number of organic compounds and significantly less ice than was supposed to be detected.
These and other data suggest that the comet, contrary to the opinion of researchers, was formed in the Kuiper belt, located beyond the orbit of Neptune. Initially, it was believed that the place of formation of 67P is located much closer to Jupiter.
The data of the Rosetta and Fila apparatuses also related to the features of the comet's nucleus, its gravity and magnetosphere. A huge part of them has yet to be analyzed. Regardless of the picture that will develop after studying and considering all the information, the Rosetta mission and mission are by far one of the most ambitious space projects implemented. Many scientists call this event the third most important after the flight of Yuri Gagarin and the landing of people on the moon. It should be noted that Rosetta is not the last research mission, the purpose of which is to expand our knowledge of the Universe. The success of the flight to Comet 67P stimulated the development of new projects. Several of them are preparing to start in the near future.