NASA has set up two missions to explore whether life could exist on Venus

NASA has selected two missions called DAVINCI+ and VERITAS to study the "lost habitable" world of Venus. Each mission will receive about $500 million in development funding, and both are expected to launch spacecraft between 2028 and 2030.

It has long been thought that there is no life on Venus because of its extremely high temperature. But late last year, scientists studying the planet's atmosphere announced the surprising (and controversial) discovery of phosphine. On Earth, this chemical is primarily produced by living organisms.

The news has reignited interest in Earth's "twins," prompting NASA to plan state-of-the-art missions to take a closer look at Venus' planetary environment -- which could suggest conditions for life to exist.

life condition

Ever since the Hubble Space Telescope revealed the sheer number of nearby galaxies, astronomers have become obsessed with finding exoplanets in other star systems, especially those that appear habitable.

However, there are certain criteria for judging whether a planet is habitable or not. It must have a suitable temperature, atmospheric pressure similar to Earth and available water.

In this regard, if Venus is outside our solar system, it probably won't attract much attention. Its skies are filled with thick clouds of sulfuric acid (dangerous to humans), the land is desolate and full of extinct volcanoes, and 90 percent of the surface is covered in fiery lava flows.

Still, NASA will look for the environmental conditions on Venus that once supported life. In particular, any evidence that Venus may have once had an ocean would change all our current models of Earth.

Interestingly, at an altitude of about 50 kilometers (30 miles) above the surface, conditions on Venus are far less severe. In fact, the pressure at these high altitudes is greatly reduced, and the environment becomes more earth-like, with breathable air and pleasant temperatures.

If life (in the form of microbes) does exist on Venus, then this may be where it is.

DAVINCI+ tasks

NASA's DAVINCI+ (Deep Atmospheric Venus Survey for Noble Gases, Chemistry, and Imaging) mission has several science goals, involving:

Atmospheric origin and evolution

It will aim to understand the origin of the atmosphere on Venus, with a focus on how it formed in the first place, how it evolved, and how (and why) it differs from the atmospheres of Earth and Mars.

Atmospheric composition and surface interactions

This will involve understanding the history of water on Venus and the chemical processes at work in its lower atmosphere. It will also try to determine whether Venus once had oceans. Since life on Earth originated in our oceans, this would be the starting point for any search for life.

surface properties

This aspect of the mission will gain insight into the geographically complex tessera regions (with highly deformed topography) on Venus and will investigate their origin and tectonic, volcanic and weathering history.

The findings could shed light on how Venus and Earth started out in similar ways and then diverged during their evolution.

Once the DAVINCI+ spacecraft reaches Venus, it will drop a spherical probe with sensitive instruments into the Venusian atmosphere. During the descent, the probe will sample the air, continuously measure the atmosphere as it descends, and return the measurements to the orbiting spacecraft.

The probe will carry a mass spectrometer, which can measure the masses of different molecules in the sample. This will be used to detect any noble or other trace gases in Venus' atmosphere.

In-flight sensors will also help measure the dynamics of the atmosphere, with cameras taking high-contrast images during the probe's descent. Only four spacecraft have returned images from the surface of Venus, and the last such image was taken in 1982.

VERITAS tasks

Meanwhile, the VERITAS (Venus Emissivity, Radio Science, InSAR, Topography and Spectroscopy) mission will map surface features to determine the planet's geological history and learn more about why it developed so differently from Earth.

Historical geology provides important information on ancient climate changes, volcanic eruptions, and earthquakes. This data can be used to predict the likely size and frequency of future events.

The mission will also seek to understand the inner geodynamics that shape the planet. In other words, we might be able to draw a picture of the movement of the continental plates on Venus and compare it to Earth.

Like the DAVINCI+ mission, VERITAS will take full-planet, high-resolution topographic images of the Venusian surface, mapping surface features including mountains and valleys.

Meanwhile, the Venus Emissivity Mapping (VEM) instrument on the orbiting VERITAS spacecraft will map surface gas emissions with precision that will be able to detect near-surface water vapor. Its sensors are so powerful that they will be able to see through thick clouds of sulfuric acid.

Insights into the condition of Venus

The most exciting of the two missions is the orbiting Earth probe. In the 1980s, four landers successfully reached the surface of Venus, but only operated for two days due to squeezing pressure. The pressure there is 93 bar, the same pressure that is 900 meters below sea level on Earth.

Then there's lava. Many lava flows on Venus stretch hundreds of kilometers, and the fluidity of this lava may be enhanced by Venus' average surface temperature of 470°C.

Meanwhile, the "shield" volcanic bases on Venus are 700 kilometers (435 miles) wide and have an average height of about 5.5 kilometers. The largest shield volcano on Earth, Mauna Loa in Hawaii, is only 120 kilometers wide at the base.

Only three celestial bodies in our solar system have confirmed active volcanoes: Earth, Mars, and Jupiter's moon Io. But recent research suggests that the volcano Idunn Mons on Venus may still be active.

The information obtained from DAVINCI+ and VERITAS will provide important insights not only into how Venus formed, but how any rocky, life-giving planet could form. This will also provide valuable exploration experience for us to find habitable planets outside our solar system.