Nasa announces two new missions to Venus

Missions are expected to blast off between 2028 and 2030

This image made available by Nasa shows the planet Venus made with data from the 'Magellan' spacecraft and Pioneer Venus Orbiter. Nasa/JPL-Caltech via AP

Nasa on Wednesday announced two new missions to Venus that will launch at the end of the decade.

The missions will learn how our nearest planetary neighbour became a fiery mass while Earth thrived.

"These two sister missions both aim to understand how Venus became an inferno-like world, capable of melting lead at the surface," said Bill Nelson, the agency's newly confirmed administrator.

"They will offer the entire science community the chance to investigate a planet we haven't been to in more than 30 years."

The missions have been awarded about $500 million under Nasa's Discovery Programme and each is expected to be launched between 2028 and 2030.

Both missions were picked from a competitive, peer-reviewed process based on their scientific value and feasibility of their plans.

Davinci+, which stands for Deep Atmosphere Venus Investigation of Noble gases, Chemistry and Imaging, will gather more detail on the composition of Venus's primarily carbon dioxide atmosphere to learn how it formed and evolved.

It also seeks to determine whether the planet once had an ocean.

A descent sphere will plunge through the dense atmosphere that is laced with sulphuric acid clouds to precisely measure the levels of noble gases and other elements to learn what gave rise to the runaway greenhouse effect we see today.

Davinci+ will also beam back the first high-resolution images of the planet's tesserae, geological features approximately comparable with Earth's continents, the existence of which suggests Venus has tectonic plates.

The results could reshape scientists' understanding of terrestrial planet formation.

The other mission is called Veritas, an acronym for Venus Emissivity, Radio Science, InSar, Topography and Spectroscopy.

It will aim to map the Venusian surface from orbit and delve into the planet's geological history.

It will use infrared scanning to determine rock type, which is largely unknown, and whether active volcanoes are releasing water vapour into the atmosphere.

Using a form of radar that is used to create three-dimensional constructions, it will chart surface elevations and confirm whether earthquakes are still happening on the planet.

While the mission is led by Nasa, the German Aerospace Centre will provide the infrared mapper while the Italian Space Agency and France's Centre National d'Etudes Spatiales will contribute to the radar and other parts of the mission.

"It is astounding how little we know about Venus," said Tom Wagner, Nasa's Discovery Programme scientist.

"But the combined results of these missions will tell us about the planet from the clouds in its sky, through the volcanoes on its surface, all the way down to its very core.

"It will be as if we have rediscovered the planet."

Nasa's last Venus orbiter was Magellan, which arrived in 1990, but other vessels have made fly-pasts since.