The missions, which have each been awarded $500m (£352m) in funding, are due to launch between 2028 and 2030.
- Nasa administrator Bill Nelson said the missions would offer the "chance to investigate a planet we haven't been to in more than 30 years".
- The last US probe to visit the planet was the Magellan orbiter in 1990.
- However, other spacecraft - from Europe and Japan - have orbited the planet since then.
- The missions were picked following a peer review process and were chosen based on their potential scientific value and the feasibility of their development plans.
As planetary scientists began meeting in person again, Venus specialists had a special celebration to mark the occasion.
The Venus community has been awaiting missions for decades. Currently, only one dedicated mission is currently studying our next-door neighbour, and NASA's last robotic Venus mission ended in 1994. NASA and its European counterpart committed to launching three new missions in the early 2030s within only a few weeks in 2021, however.
This year's Lunar and Planetary Science Conference (LPSC) was held in Texas, and many planetary scientists focused on Venus.
Jörn Helbert, a planetary scientist at the German space agency DLR, said during a talk on Tuesday, “I would like to just take a moment to acknowledge how fantastic it is that we've actually moved now from talking about what proposed Venus missions could do to actually talking about what our missions will do at Venus. This is just an incredible moment."
NASA chief Bill Nelson announcing the missions
Within a matter of weeks in June 2021, NASA committed to two new Venus missions, VERITAS and DAVINCI, while the European Space Agency greenlit its own mission, EnVision. It is anticipated that all three will conduct the bulk of their observations in the early 2030s and that these projects will revolutionize the scientific study of Earth.
Venus scientists have taken to celebrating "the decade of Venus," and the moment has been a long time coming. "The Venus community, we are tight," said Martha Gilmore, a planetary geologist at Wesleyan University in Connecticut who focuses on Venus and who gave a plenary talk to the conference. "We've been battling this whole time and proposing."
In spite of the decades-long delay in NASA missions, scientists' efforts have not gone to waste: Neither VERITAS nor DAVINCI were first-time proposals, allowing scientists to refine their designs until they are selected. Despite this, Venus boosters have had difficulty convincing scientists to devote their careers to a planet that has such a limited number of missions.
Gilmore referred to her first LPSC in 1992, during NASA's last Venus era, noting that the program included three comprehensive days of Venus talks. Despite the planet's current state, presentations on Tuesday focused on the planet next door, with talks covering topics such as strange geological features, Venus' long-lost oceans, and cloud activity.
Venus may have ongoing volcanism today
NASA's Jet Propulsion Laboratory's Sue Smrekar, a planetary scientist with VERITAS, who first proposed the mission to NASA in 2015, kicked off the event with an overview of the mission.
Veritas, which is scheduled for launch in 2027, is designed to peer through the thick clouds of Venus and provide scientists with their first glimpse of its surface since the Magellan mission ended in 1994. Instruments onboard the spacecraft will provide information about rock composition, geological activity, and the interior of the planet.
"VERITAS will produce these incredible foundational datasets that will just tell us so much about Venus and pave the way for the 'decade of Venus' and all the exciting investigations that are going to be discussed today and hopefully many, many future missions," Smrekar said.
One of the instruments aboard VERITAS, the Venus Emissivity Mapper, will see a near-twin fly on ESA's mission EnVision, targeting launch in the early 2030s. With their staggered arrivals, the pair of instruments will complement each other, Helbert said during his presentation, particularly because Venus is the only inner planet where rock types have not been mapped across the full surface. The instruments will also be able to identify whether Venus' surface hosts any active lava flows: such features would glow compared to a cooler rock nearby and give clouds above an eerie shine.
Other speakers teased their own anticipated science returns from the trio of Venus missions. While the strength of VERITAS and EnVision's science focuses on the planet's surface, DAVINCI's observations will emphasize Venus' thick, carbon-rich atmosphere. Unlike the other two missions, DAVINCI, which is targeting launch in 2030, includes two components: the main spacecraft and an atmospheric probe that will spend about an hour coasting down to the surface.
DAVINCI's probe will land in a particularly complex area called Alpha Regio, the target of research presented by Margaret Deahn, a graduate student working with Gilmore at Wesleyan University. "It's pretty intimidating," Deahn said of the landscape, where she is working to pick apart a web of ridges, troughs and other features in advance of the probe's arrival.
Gilmore attributed the Venus community's sudden wealth of missions to both the scientists' work and two lucky breaks. One was the September 2020 announcement of phosphine detected in Venus' atmosphere. On Earth, the chemical is associated with life, and the detection spurred a rush of renewed interest in the planet's habitability throughout time.
Another stroke of luck was the cross-disciplinary partnership formed in recent years with scientists interested in exoplanets as the number of known alien worlds has exploded. Scientists usually collect information about an exoplanet's size and orbital distance from a star as the first data points. According to these criteria alone, Earth and Venus appear essentially the same, and many exoplanets resemble Venus.
"Exoplanets: who knew, they're everywhere and a lot of them are Venus-size," Gilmore said. "The exoplanet folks and the Venus folks have become like BFFs because we're trying to understand how an Earth-size planet happens."
But if getting a spacecraft mission to Venus has been difficult, getting one to an exoplanet is impossible. "This is a rather haunting thing to think about," Stephen Kane, an astronomer at the University of California, Riverside said during his presentation. Scientists interested in finding rocky, potentially habitable worlds outside our solar system can only study the few terrestrial planets in our own system from spacecraft. Venus is a clear reference point for questions concerning its atmosphere because it has by far the most massive atmosphere of any planet.
While Venus scientists will still face a four-decade drought in NASA data, they are finally looking forward to a brighter future. Gilmore told the audience that she changed her license plate to read "TO VENUS" to commemorate the event.
"There's so much that we can do with this opportunity to go to Venus," she said. "We are all invested, I think, in learning everything we can with this opportunity."
