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A radar image from the Magellan spacecraft shows Venusian surface features. (Image courtesy NASA/JPL)

Venus is neglected. NASA hasn’t had a spacecraft at Venus since the Magellan orbiter ended its mission by intentionally plunging into the Venusian atmosphere in 1994. While there are currently more than a dozen spacecraft studying Mars, Venus has only one — the Japanese Akatsuki climate orbiter. 

All that is about to change with the announcement of two new missions headed to study this near twin of Earth.

We have never discovered a more Earth-like planet than Venus. Venus is roughly the same size and mass as Earth, and it orbits within the habitable zone of our sun — an orbital band where liquid water can exist on a planetary surface. If we discovered a Venus-like world around another star, headlines would blare that we had found Earth 2.0. 

A closer look reveals stark differences between the two worlds. Venus is covered by a thick atmosphere comprised mostly of carbon dioxide (CO2). The resulting greenhouse effect of all that CO2 has turned Venus into the hottest planet in the solar system, with surface temperatures of about 900 degrees.

That surface is obscured from our view by a thick, global blanket of clouds composed of sulfuric acid. The thick atmosphere also means the air pressure on Venus is about 90 times greater than it is on the surface of Earth, which is about the same amount of pressure you would experience if you were beneath a mile of water. 

What processes took place on Venus to produce these hellish conditions?

The two new missions announced by NASA on June 2 aim to answer this and many other questions. 

DAVINCI+ (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging) will make precision measurements of the composition of Venus’ atmosphere. It will also return the first high-resolution images of unique geologic features on Venus called “tesserae,” which may help us understand whether the planet has or had plate tectonics.

A technology demonstration mission called CUVIS (Compact Ultraviolet to Visible Imaging Spectrometer) on board DAVINCI+ will try to determine the nature of the unknown ultraviolet absorber in Venus’ atmosphere that has so far defied discovery. 

VERITAS (Venus Emissivity, Radio Science, InSAR, Topography and Spectroscopy) will map the surface of Venus using interferometric synthetic aperture radar (the “InSAR” acronym within the VERITAS acronym). It will also study the rocks of Venus and determine whether the planet’s volcanoes are releasing water vapor into the atmosphere. 

Both missions are set to launch toward the end of this decade. 

The Morning Sky

Saturn rises a little after midnight, followed closely by Jupiter. Neptune, Uranus and Pluto are also up in the early morning east, but these three worlds are invisible without optical aid. The constellation Cygnus, the swan, flies through the band of the Milky Way directly overhead before dawn. 

The Evening Sky

The moon returns to the evening sky on Friday, appearing just below Venus low in the west after sunset. Watch as the moon sets a little later and appears a bit more full with each passing night. On Sunday, the moon appears just above Mars in the western evening sky. 

Dan Price is a NASA/JPL Solar System Ambassador and informal educator. Join him at Josephine Sculpture Park on June 12 for a telescopic Night Sky Tour. Please see the JSP website for details. Have a question about astronomy or space science? Send an email to dan@starpointestudio.com and it might be featured in a future column.

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