Venus is that “star”, which appears in the sky along with the first rays of the Sun and reappears at dawn. Romantics sang about it, and its beauty was immortalized by giving it the name of the most beautiful of Greek goddesses – Venus, the goddess of love and beauty.
But it turned out that this planet possesses quite a temper, and hides its secrets from the eyes of curious explorers. However, it never stopped the scientists. The Soviet Union has sent its first automatic interplanetary station (AIS) to Venus, exactly two months prior to Yuri Gagarin’s flight (April 12, 1961).
A hell-like planet
Venus is the brightest object in our sky after the Sun and the Moon. It’s brighter than the brightest star and you can tell it apart from the others by the smooth white light it emits.
It is located closer to Earth than any other planet. The distance between us and Venus fluctuates at times from 38 to 261 millions kilometers. In comparison, the shortest distance to Mars is almost 56 mln kilometers. And it belongs to the planets of the Earth group.
At first, two planets were considered as the object for possible colonization: Venus and Mars. But it turned out that the conditions on the “Morning star” do not allow for human survival:
- The temperature on the surface can rise up to 475 degrees Celsius. This is due to the greenhouse effect, caused by the atmosphere, consisting of 96% carbon dioxide.
- The atmospheric pressure on the surface exceeds the one on Earth by 93 times.
- And add to all of this the fact that the clouds consist of vapor of pure sulfuric acid.
The history of study of the planet
The Soviet Union was exploring this planet for over twenty years, and sent nearly 20 AIS during this time. Some of these stations successfully completed their scientific tasks in the vicinity of the planet, as well as on its surface,
The task was made harder by the fact that we barely knew anything about Venus, the first AIS were made based on pure assumptions. Let’s provide some chronology:
- Year 1961. AIS “Venus 1” entered the heliocentric orbit of Venus, 100 thousand kilometers away from its surface.
- Year 1965. AIS “Venus 3” was the first spacecraft in history to reach the surface of the second planet of our Solar system.
- On December 15, 1970, the first in history soft landing of a spacecraft on the surface of Venus took place – it was AIS “Venus 7”.
- Year 1982. AIS “Venus 13” shot colored panoramic photos of the surface, using the special equipment and sent them to Earth.
- Year 1986. A planetary rover with a wheel-stepping propulsion device, HM-VD-2.
Soviet planetary rover HM-VD-2
To make the exploration of this hard-to-navigate planet more effective, the need for mobile research complexes has emerged. Scientists and engineers developed a unique venusrover with properties that allow it to work on the surface of Venus for a relatively long time.
At the time, this complex received a number of innovative technological solutions.
Chassis
A unique chassis was developed specifically for this venusrover. It consisted of six wheels with grousers. The advanced support surface took up almost the total width of the robot. Every wheel had its own rotating motor.
Flexible articulations
A flexible joint connected with an adjacent pair each pair of wheels. This provided each individual pair with a huge rate of freedom, they were able to:
- turn to the side;
- move up or down, while climbing over obstacles.
The venusrover could climb over obstacles one meter in height, although its chassis was smaller.
The shape of wheels
The wheels had a streamline shape, which, together with the wide running gear, allowed the rover to move through high blockage quite effectively. If there were steep slopes with loose primer, the wheel-stepping mechanism tuned in.
The wheel-stepping movement principle
Since each one of 2 sections, which were connecting the wheel pairs, could measure length, to grip onto the edge of a steep cliff, the HM-VD-2 extended the forward pair up, using it to cling onto the edge and then pulled the others. The optimal movement mode was individual for every specific location and consisted of a length of a step, speed of wheel extension, and their speed.
Obstacle detection
The venusrover was detecting obstacles by the position of the running gear. If the lateral tilt angle of any pair of wheels was exceeded, the system gave a stop signal to avoid rolling over. After that, the robot would back up and change direction. If the forward wheels of XM would drop down, it means that there is a cliff in front. It would stop, back up, and change direction once again.
A power unit
Taking the peculiarities of Venus into consideration, such as absence of sun, constant winds, the venusrover was equipped with a wind turbine, consisting of paddle-turning engine and an electric generator, which powered the battery made out of a special kind of electrolyte. The wind sensors were used to automate the turning of the wind engine.
Robot’s electronics
The batteries powered the electronics, which were quite resistant to the high temperatures. At the time, scientists thought that they would use the microcircuits with specific diamond membranes, able to keep working at 800 °C.
Unfortunately, the almost ready venusrover didn’t get to fly anywhere. It was due to the fact that the vector of attention has changed. Because of the rough environment of Venus, it was decided to focus the world’s attention on Mars.
USA is making their own venusrover
Nowadays, in the laboratories of the nuclear movement, in the USA, NASA is creating a project called AREE “Automation Rover for Extreme Environments”. The idea is: automation of a venusrover will be provided by a wind turbine, as the winds on Venus are strong and constant. The turbine will start the complex system of gears, springs and various parts, which make up the rover.
The engineers of the project must solve many exotic problems, such as, how will the rover “know” about the obstacle in front of him, around which he needs to navigate, without any electronics?
Russians and Americans have agreed on conducting and executing the mission “Venera D” together. The primary task of which is researching the composition of the atmosphere of Venus, the formation of the planet itself and to discover the reasons for such a powerfull greenhouse effect.
If, at the end of the day, the AREE willdevelop the venusrover, it will allow to make a huge step forward in the study of the planet, because up to this day, only soviet AIS visited its surface, which were able to work for only 2 hours. Mission is planned for 2029-2031.
