Venus has been popular since ancient times as dawn, shining brightly in the evening and dawn. Although it is the closest planet to Earth, it may be a little overshadowed by Mars, which is crowded with spacecraft due to the concern about the existence of life. Meanwhile, NASA announced earlier this month that it will launch two Venus probes in 2028-30. It is said that it will challenge detailed observations of the atmosphere and geology. The only Japanese spacecraft Akatsuki is in operation on Venus, but the United States will be the first challenge in about 35 years.
Venus is a rock star that orbits just inside the Earth. The distance from the earth is 39.5 million kilometers, which is the closest planet to the shortest 55.8 million kilometers of Mars on the outside. Since their size and weight are close to those of the Earth and their internal structures are very similar, they are also called twin sibling stars.
However, its true identity is full of mysteries. It is covered with a thick atmosphere containing carbon dioxide as the main component, and sunlight does not reach the surface of the earth because it is blocked by a cloud of sulfuric acid. The surface of the earth is a burning hell of 90 atmospheres and 460 degrees. A strong wind of 100 meters per second, Super Rotation, is blowing in the upper atmosphere. Moreover, the orbital period is about 225 days and the rotation period is about 243 days, which means that the rotation period takes a long time.
Venus is rough and bends against the earth full of life. Why did the siblings look so different? If you search for the cause, you should deepen your understanding of Venus itself as well as the Earth.
Detailed exploration of the atmosphere and geology
The newly decided spacecraft are Da Vinci Plus and Veritas. Da Vinci Plus consists of an orbiter that approaches Venus multiple times and a spherical device that observes while descending in the atmosphere. By examining the composition of the atmosphere in detail, we aim to elucidate the history of Venus and the cause of the burning hell on the surface of the earth. It is said that Venus once had a sea of water in which life could exist for billions of years, and verification of this is also an issue. We will also try high-resolution shooting in the highlands called Tessera, which has been transformed intricately. It is the first time since the former Soviet Union in 1985 to plunge into the atmosphere of Venus and explore it.
Veritas is a lapping machine. Radar observations are used to examine almost the entire topography of Venus and create a three-dimensional map. Explore the geological history to see if there are still mechanisms such as plate tectonics and volcanic activity. The distribution of rocks will be clarified by infrared observation. Along with Da Vinci Plus, we will approach the mystery of the formation of Tessera.
Both probes were decided as part of NASA’s Discovery Program, which began in the 1990s to explore the solar system at low cost and with high efficiency. The budget is about 500 million dollars (about 55 billion yen) each. Both were defeated by two asteroid explorers in the previous 2017 selection but were selected from the four finalists on the 2nd of this month. The concept of the spacecraft of Jupiter’s satellite Io and the spacecraft of Neptune and the satellite Triton was rejected.
In response to the decision, NASA Director of Science Thomas Zabouken said, I want to understand how this earth-like planet became like a greenhouse with cutting-edge technology. The goal is big, beyond the solar system, and a new research field, the solar system. I want to extend it to (understanding) the outer planets.
Interest in the solar system, not just the moon and Mars
Venus became one of the stages of the US-Soviet space race during the Cold War, but it is undeniable that the heat has cooled since then. Entering this century, the European orbiter Venus Express was explored in 2006-14. Currently, Akatsuki, who approaches the mystery of the atmosphere and super-rotation, is the only one that continues to operate. In the United States, the orbiter Magellan operated from 1990 to 1994 was the last. This is in stark contrast to the fact that the United Arab Emirates (UAE) and China’s new entrants have also succeeded in exploring Mars earlier this year.
In the background, it is difficult to develop observation equipment that can withstand the high temperature and high pressure of Venus for a long period of time, and it may be technically difficult to insert the inner planets into orbit compared to the outer planets outside the earth. It is also natural to focus more on Mars, where future manned exploration is insight.
Regarding NASA’s new plan, Junya Terazono, a planetary scientist familiar with solar system exploration, said, Venus exploration in the 1960s and 1970s was almost the only place in the former Soviet Union, and since then it has become thin. I have a sudden impression that I chose two of them, but I think there is also a simple aim to show that NASA is interested not only in the moon and Mars but also in the entire solar system.
Following NASA, the European Space Agency (ESA) announced on the 10th that it has decided on the Venus probe Envision. Launched an orbiter in the early 2030s, Providing an overview from the core to the upper atmosphere to examine how and why Venus and Earth have evolved so differently.
As the results of Akatsuki’s exploration continue to appear in the form of treatises and the results of Da Vinci Plus, Veritas, and Envision, the mysterious real image of Venus will be revealed little by little. Ten or twenty years from now, humankind may look up at the evening star and the morning star in a slightly different mood.