What tricks have various countries prepared for the "gold rush"?

Venus was a favorite of early human deep space exploration. In the 1960s and 1980s, the Soviet Union and the United States sent multiple probes to Venus. In June 2021, the United States and Europe announced that they would send "special envoys" to visit Venus. Earlier, Russia also announced plans to "return to Venus". Humans are showing new interest in this "twin brother" of the Earth.

Magellan Venus probe captured a picture of the surface of Venus

How did humans explore Venus in the past?

One of the reasons why Venus gradually faded from human sight was that the Soviet Union’s economic difficulties and eventual disintegration in the late 1980s and early 1990s made it too busy to explore Venus. To date, the Venera-Gallay-1/2 probe has become the last planetary probe successfully launched by the Soviet Union/Russia. In addition, since the 1990s, NASA has focused its unmanned planetary exploration on Mars, because people have found traces of water on the red planet, attracting multiple orbiters, landers and rovers from different countries to "go one after another" to find out. Due to the very high surface temperature of Venus, even the most successful lander can only survive a few hours on Venus. Therefore, compared with Mars, humans have obtained much less data on Venus.

Venus is similar in size, mass and composition to Earth, and is a neighbor in the inner solar system. However, due to the extremely severe greenhouse effect it has experienced and the thick toxic atmosphere it is now surrounded by, Venus is often regarded as Earth's "evil twin". After research, scientists believe that Venus has not always been "purgatory". Billions of years ago, it was a habitable planet like Earth, with a mild climate, suitable temperature, crisscrossing rivers and vast oceans, but the greenhouse effect and other reasons about hundreds of millions of years ago changed the fate of Venus.

Mariner 10's image of Venus

In recent years, with the rise of the search for extraterrestrial life, Venus has become a target of interest for astrobiologists. Scientists announced last September that based on the analysis of ground-based infrared and microwave observation data, they found that there may be phosphine in the atmosphere of Venus. On Earth, phosphorus is produced by life in an anaerobic environment. The phosphine found in the atmosphere of Venus may be produced by life in the upper atmosphere, but some scientists have questioned this discovery.

The reason why scientists who study the evolution of exoplanets have a keen interest in Venus is that they believe that understanding the differences between Venus and Earth is very important for understanding how planets and habitable conditions evolve. There is another practical reason why humans are once again turning their attention to Venus. Knowing exactly how Venus has changed from a habitable planet to a scorching inferno will greatly help humans better protect the Earth. Currently, humans are cutting down forests on a large scale, burning fossil fuels and other behaviors, which are making the Earth's environment worse and worse. The amount of heat-absorbing greenhouse gases such as carbon dioxide emitted by humans into the atmosphere has increased year by year, and the greenhouse effect of the atmosphere has also increased accordingly. The series of problems it has caused have attracted widespread attention. The greenhouse effect can be traced back to the study of Venus, because the strong greenhouse effect there has led to extreme warming of its atmosphere.

Since the beginning of the new century, only Europe and Japan have carried out Venus orbiter missions. In addition, humans can only use other probes that fly by Venus for limited observations. Many researchers have been advocating for a comprehensive and in-depth Venus exploration mission.

What preparations have countries made to explore Venus ?

1. NASA: Da Vinci+ and Truth

On June 2, NASA Administrator Nelson announced that two Venus exploration missions were selected under the latest round of mission selection for NASA's Discovery program. The probes, named "Da Vinci+" and "Veritas," will be sent to Venus in the late 2020s. Both sister missions aim to understand how Venus became a purgatory-like planet that can melt lead on its surface. This is the first time NASA has announced an unmanned mission to Venus in more than 30 years, and the first dedicated Venus exploration mission since NASA launched the Magellan Radar Mapping Orbiter in 1989. The Discovery program, which was launched in 1992, is designed to support regular cost-capped, scientifically targeted exploration missions in the solar system.

The full name of "Da Vinci+" is "In-depth Investigation of Venus's Inert Gas, Chemistry and Imaging Atmosphere+". It will fly over Venus twice to measure its atmospheric circulation and thermal radiation and other related data. After that, a spherical descender will be sent into the atmosphere of Venus to accurately measure the atmospheric composition at different altitudes. This will help scientists understand the formation and evolution of Venus' atmosphere, determine whether there has been an ocean on Venus, and help understand how its runaway greenhouse effect occurs. The camera on the descending probe will take high-resolution images of geological features called "mosaic blocks". Those geological features may be similar to continents on Earth.

The Da Vinci+ probe will carry a probe into the atmosphere of Venus to determine its composition.

The mission, which stands for Venus Radiometry, Radio Science, Synthetic Aperture Radar Interferometry, Topography and Spectroscopy, will use a synthetic aperture radar system to map Venus from orbit, including surface rock types, to create the first map of Venus' surface composition, which is important for understanding the history of water on Venus. In some ways, it is an upgraded version of NASA's Magellan probe, with much more accurate measurements. It will also search for infrared radiation, which could help scientists determine if there are active volcanoes there.

NASA's 'Truth' Venus Probe

The Da Vinci+ mission will be led by NASA's Goddard Space Flight Center, while the Veritas mission will be led by the Jet Propulsion Laboratory. The probes for both missions will be built by Lockheed Martin. Each mission is estimated to cost $500 million and is scheduled to launch between 2028 and 2030. The optimal launch window to Venus occurs approximately every 19 months. Launch contracts will be signed in the later stages of each mission's development.

NASA Administrator Nelson announces that Da Vinci+ and Truth will travel to Venus in the late 2020s

In addition to the main scientific payload, both missions will also carry technology verification devices. "Truth" will carry an upgraded model of a deep space atomic clock that was launched on an Earth-orbiting satellite in 2019, which will help with radio science observations and autonomous maneuvers of the probe. "Da Vinci+" will carry a new ultraviolet imaging spectrometer.

"It's surprising how little we know about Venus, but the combined results of these two missions will tell us about the planet, including its clouds in the sky, the volcanoes on the surface and even its inner core. It's like we've rediscovered the planet," said Wagner, a scientist for NASA's Discovery Program.

2. ESA: Outlook to succeed Venus Express

Coincidentally, just one week after NASA announced the selection of two Venus exploration missions, the European Space Agency also selected a Venus orbiter exploration mission as its next mid-level science mission. The agency announced on June 10 that "EnVision" will be its next M-class (mid-level) science mission. The orbiter will be equipped with a suite of spectrometers, sounders and radar instruments, with the goal of answering the following questions: Venus is similar in size and composition to Earth, but why has Venus experienced such dramatic climate changes? What processes did Venus go through to evolve to its current state? Will Earth's future fate be like Venus'?

ESA's "Inspection" Venus orbiter

The "Outlook" mission will be launched as early as 2031 by an Ariane 6 rocket. After reaching Venus, it will use the Venusian atmosphere for aerobraking and finally enter the final scientific orbit to carry out a four-year scientific exploration mission. ESA has not disclosed the estimated cost of the "Outlook" mission, but under the framework of the agency's "Cosmic Vision" scientific mission, the cost of M-class missions is planned to be controlled at around 500 million euros (610 million US dollars).

Venus is not new to ESA. In 2005, ESA launched the Venus Express probe, which was mainly used to study the aerodynamics and chemical composition of the surface of Venus, understand the atmospheric characteristics of the surface of Venus, and study the impact of the solar wind on the surface air of Venus and the development and evolution of the planet. "Outlook" will continue the orbital exploration mission of ESA's "Venus Express". Unlike "Venus Express", which focuses on atmospheric research, "Outlook" will determine the nature and status of Venus' geological activities and their relationship with atmospheric activities, and better understand why the evolutionary paths of Venus and Earth are so different.

Schematic diagram of ESA's Venus Express in orbit

ESA and NASA did not coordinate the selection or timing of these missions, but both sides welcome the complementarity that exists between them. The United States and Europe are participating in each other's missions. The synthetic aperture radar called VenSAR on the "Prospect" will be provided by the United States Jet Propulsion Laboratory, while the Italian Space Agency and the French National Center for Space Studies are providing a similar radar for the US "Veritas" probe, and the German Aerospace Center will provide the infrared mapper for Veritas.

3. Russia and India: "Venus D" and "Venus Ship"

Some other countries are also planning Venus exploration missions. Russia, which was a leader in Venus exploration during the Soviet era, has been promoting a mission plan called "Venus D" in recent years. The plan includes an orbiter and a lander, which may have some involvement from NASA and is scheduled to be launched no earlier than 2026. Dmitry Rogozin, general manager of the Russian State Space Corporation, has been saying that he wants Russia to return to Venus. He said that Venus has always been a "Russian planet" and studying Venus will help scientists understand how to deal with climate change on Earth.

Russia's Venus D mission

India is developing a Venus orbiter called "Venus Ship", which weighs about 2,500 kilograms and will carry a set of scientific payloads including synthetic aperture radar and other instruments. The main goal is to map the surface and subsurface of Venus, while studying the chemical composition of Venus' atmosphere and its interaction with the solar wind. "Venus Ship" is planned to be launched by India's GSLV-2 rocket. In order to allow the probe to carry more instruments or fuel, the mission team is also evaluating whether to use the more powerful GSLV-3 rocket. "Venus Ship" will be India's first Venus exploration mission and will carry out research for more than four years.

India's Venus Probe

4. Private project: "Electron" will send "Photon" to Venus

It's not just deep-pocketed governments that are interested in Venus. Rocket Lab, a manufacturer of small launch vehicles and small satellites, will also take the lead in launching a small-scale Venus exploration mission. Rocket Lab CEO Beck has repeatedly stated that the company is embarking on a small satellite mission that will penetrate the atmosphere of Venus to search for phosphorus or other markers of life. The mission will be launched by the company's own Electron rocket and will use a model of its Photon satellite platform. The Photon platform has been verified in orbit during a launch. "Venus is the most underestimated planet in the solar system. The Earth may learn from the lesson of Venus's runaway greenhouse effect. Scientifically, we can learn a lot from Venus," said Beck.

Photon Satellite Platform

Other private projects have also begun to take shape. The Breakthrough Initiatives Foundation, funded by billionaire Yuri Milner, announced in 2020 that it would fund research into potential life on Venus.

Some say Venus is a "Rosetta Stone" that allows us to understand how planetary climates change, how habitable conditions evolve, and what happens when the surface ocean disappears. Let us wait for more discoveries from all kinds of "gold rushes" to unveil the mystery of Venus soon.