For future conquerors of other planets. How to create space maps

Category: English  |   12 Апрель 2021    

For future conquerors of other planets. How to create space maps

In October 2021, Russia will resume the lunar program, which was discontinued during the Soviet era. The first should go to the surface of a natural satellite of the Earth is the automatic station "Luna-25". Its launch is scheduled for October 1. In 2024, it is planned to launch the Luna-26 orbital mission, and in 2025 - the Luna-27 lander. The next mission - Luna-28 - will return the regolith to Earth, the device will be created in the guise of a take-off and landing module to work out the landing before a manned mission, scheduled for 2030.


To choose a landing site and prepare for the flight, scientists and astronauts will need maps of the Earth's natural satellite. Irina Karachevtseva, head of the complex laboratory for the study of extraterrestrial territories of MIIGAiK, Elena Bekchanova, senior engineer-geodesist of the Department of Topographic and Geodetic Works of Roskartography, and Oleg Evstafyev, leading engineer-geodesist of the Department of Topographic and Geodetic Works of Roskartography, told about what maps of other planets already exist, how they are created and what will appear in the future.


From Earth and from space


To create maps of the Earth, three methods are used: ground-based (using topographic and geodetic surveys), aerial photography (using aircraft and drones) and space (with the acquisition of remote sensing data from artificial satellites). Larger — scale maps are created from orbit, and more detailed maps are created using aerial photography and ground-based methods.


"To date, the maximum permissible remote sensing data is at best 30-50 cm, and at worst 100 m. Now we are creating a single electronic cartographic basis for the territory of the Russian Federation with a resolution of 20 cm on the territory of urban settlements and 1 m on the territory of the subjects of the Russian Federation as part of the implementation of the national project "Digital Economy", and this experience may be useful when working on creating maps of the celestial bodies of the Solar system," said Yevstafyev, specifying that on Earth such a resolution is possible only with the use of aerial photography, because it will not be possible to achieve it in space photography.


The map, the specialist explained, is a reduced, generalized, conventionally symbolic image of the Earth, other planets or the celestial sphere, built according to a mathematical law, that is, in scale and projection, with reference to a certain coordinate system.


In this case, the coordinate system is fixed by reference points — physical objects that are visible on the surface. On the Ground, these are metal signs or concrete tours, fixed in a special way or buried in the ground. When creating maps using aerial photography, identification marks are also used as placemarks, which can serve, for example, curbs, concrete slabs, pillars, road markings that are clearly distinguishable in an aerial photograph. The heights in Russia are counted in the Baltic Altitude System of 1977 from the zero of the Kronstadt footstock, which is fixed in the abutment of the bridge over the bypass canal in Kronstadt. For topographic and geodetic works on other planets, it is necessary to first create and implement special reference systems for coordinates and heights developed for each of them, the specialist explains.


Detailed maps for astronauts


Unlike Earth mapping, accurate maps of celestial bodies are currently created using satellite imagery from orbiters. The main source of surface information is digital terrain models (DEM). "DEM and surface images allow us to study the topography of celestial bodies, for example, to measure the size and structure of craters, the most common landforms in the Solar System," explained Irina Karachevtseva.


"Modern images of the Moon's surface reach a resolution of 30 cm, and they are obtained from a low lunar orbit with an altitude of less than 50 km. With the help of these images, we created a DEM and new detailed maps of the areas of movement of the Soviet self-propelled vehicles "Lunokhod-1" and -2, controlled remotely from the Ground. With the help of modern digital maps, we have clarified the length of the routes made by these unique planetary rovers almost 50 years ago, " Irina Karachevtseva said.


карты луныLunokhod-2 route map


In turn, the leading engineer-geodesist of Roskartografiya noted that spacecraft that previously descended and worked on the surface of the Earth's satellite can be used as reference points on the Moon. There can also be placed objects that are clearly visible in the image to further determine the coordinates and snap the entire image.


In the presence of detailed data obtained from spacecraft, the map of the Moon can be more accurate than the Earth's, the expert believes. "The map of the Moon will be more accurate than the map of the Earth, because there is no atmosphere, so the distortion will be minimal or almost completely absent," explained Oleg Evstafyev.


The Russian Federation plans to create, among other things, a 3D map of the Earth's natural satellite. For this purpose, data from the Luna-26 spacecraft, which is scheduled to be sent in 2024, will be used. "Although a three-dimensional map of the Moon is already available, but, of course, in the case of a successful survey by the Luna-26 device, a new 3D map of the surface will be created," said Irina Karachevtseva.


"To prepare for a manned flight, we need special simulators with very detailed images, with the help of which the astronauts will get used to the appearance and features of the lunar surface, in order to better navigate when landing," Irina Karachevtseva said.


According to her, for the safe operation of scientific equipment, as well as the movement of astronauts on the Moon, "new detailed maps of specific areas in the landing area will be created."


From Mercury to Mars


The beginning of the space age allowed us to make reliable maps of distant planets. For this purpose, images of the surface obtained by spacecraft located in the orbits of celestial bodies are used.


карта меркурия

Hypsometric map of Mercury


"In this way, maps are created not only of the Moon, but also of Mars, Venus and Mercury — celestial bodies of the Earth group located closer to the center of the Solar system, having a solid surface," Elena Bekchanova emphasizes.


In the USSR, for the first time in the world, a map of the reverse side of the Moon was created on the basis of photos obtained by the interplanetary automatic station "Luna-3" in October 1959. Then the first atlas and globe of the Earth's natural satellite were developed. These works, based on the images obtained by the Soviet lunar interplanetary stations (AMS), were carried out by the staff of the State Astronomical Institute. Sternberg and the Central Research Institute of Geodesy, Aerial Photography and Cartography, " the specialist explained.


According to Bekchanova, the beginning of the space age made it possible to make reliable maps of more distant celestial bodies. "For this purpose, surface images obtained by spacecraft orbiting planets are used. This is how modern maps of not only the Moon, but also Mars, Venus and Mercury — the planets of the Earth group located closer to the center of the Solar system and having a solid surface — were created," the expert noted.


Elena Bekchanova noted that at the present stage of space research, international cooperation is widely practiced. At the same time, high-resolution images are often publicly available, so anyone can use them.


"Russian cartographers use images from foreign devices, and also participate in joint research with foreign scientists from Europe, the United States, and China," Elena Bekchanova explained.


No and it won't


There are celestial bodies in the Solar System the maps of which cannot be created. Some planets of the Solar system (for example, Saturn, Jupiter) have a gas, not a solid surface. "We will not be able to create a map of them, because when we create a digital image, it will be irrelevant, since the surface has already changed," says Yevstafyev, a leading engineer — geodesist of Roskartografiya.


According to him, the created images will display a specific slice at some point in time. In turn, Bekchanova explained that for mapping it is necessary to obtain not only an image of the planet's surface, but also to establish a coordinate system on the surface of the studied bodies, to determine the parameters of their rotation and size.


Balloon for creating maps


One of the unexplored planets is Venus. "The surface of Venus can not be seen either in terrestrial telescopes or from orbiters that conduct sounding in the optical range, as this planet is covered with a powerful layer of clouds," said the engineer-geodesist of Roskartografiya. "For this reason, Venus was studied with the help of radar," Elena Bekchanova said. According to the expert, the first "Atlas of the surface of Venus" was compiled in the USSR from the radar data of the Soviet AMS " Venus-15 "and" Venus-16", which performed in 1983-1984 the survey of about one third of the northern hemisphere of the planet.


In 2020, the scientific director of the Institute for Space Research (IKI) of the Russian Academy of Sciences, Academician of the Russian Academy of Sciences Lev Zeleny, said that the Russian Federation will develop a new program for the exploration of Venus, which includes sending at least three scientific vehicles. On board the first of them — "Venus-D — - will be two probes: one at an altitude of 55-60 km from the surface (above the clouds), and the second — at an altitude of 45-50 km (under the clouds).


"During operation, the device must transmit to Earth all the necessary information for a detailed study of the atmosphere and surface of Venus, which is not fully studied. And, of course, obtaining new accurate information with the help of more advanced devices of the XXI century should lead to the creation of new maps of Venus," Karachevtseva said.


First of all, maps of celestial bodies are needed to present in a visual form the results of space research, to ensure a safe landing, as well as to conduct experiments on the surface of planets.


"Maps of celestial bodies will also be necessary for future conquerors of other planets, for space tourists, for cosmonauts and astronauts who conduct their professional and research activities outside of our planet," concluded Elena Bekchanova.




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