A VOLCANO MAY HAVE ERUPTED ON VENUS IN 1991
Data from NASA’s Magellan show evidence that an eruption occurred during the mission.
Venus’ landscape is littered with volcanoes that were clearly active in the past. But less clear is whether any are still erupting in the present. Many researchers have suspected this is the case, citing evidence of lava flows that appear relatively recent. But direct before-and-after evidence of an eruption had not emerged — until researchers found it while combing through archival data from NASA’s Magellan mission, which orbited the planet from Aug. 10, 1990, to Oct. 13, 1994.
Robert Herrick, a planetary scientist at the University of Alaska in Fairbanks (UAF), reexamined the over 30-year-old data and presented the findings March 15 at the 54th Lunar and Planetary Science Conference, held in The Woodlands, Texas, and virtually. The results were published the same day in Science.
Herrick compared February 1991 radar imagery of the Alta Regio region to data from October of the same year. The area hosts two volcanoes: Maat Mons and Ozza Mons. Looking at the images, Herrick noticed that one volcanic vent near Maat Mons had expanded significantly between datasets. The October data also had a bright feature extending from the vent that looked like a possible lava flow.
Herrick and Scott Hensley, a former Magellan radar team member at NASA’s
Jet Propulsion Laboratory (JPL), used computer modeling to compare different geologic scenarios that could cause a square-mile-sized (2.2 square kilometers) vent to become misshapen and double in size. The best answer was an eruption.
“Only a couple of the simulations matched the imagery, and the most likely scenario is that volcanic activity occurred on Venus’ surface during Magellan’s mission,” said Hensley in a press release. He argues the finding “confirms there is modern geological activity” on the planet.
A CLOUDED FUTURE
The discovery comes as planetary scientists mobilize to save another NASA mission to Venus.
In 2021, NASA announced plans to return to Venus with two missions, including VERITAS (short for Venus Emissivity, Radio science, InSAR, Topography, And Spectroscopy). VERITAS is meant to create a 3D map of the surface and identify its composition using a near-infrared spectrometer.
But the mission recently suffered a setback. Originally scheduled to launch in 2028, it was delayed due to workforce and budget constraints. JPL is managing both VERITAS and the upcoming Psyche mission to the asteroid of the same name. VERITAS was meeting its targets, scientists say, but Psyche slipped behind schedule — and VERITAS paid the price. NASA’s Nov. 4, 2022,
announcement of the VERITAS delay gave no firm target launch date, saying only that it was now “scheduled to launch no sooner than 2031.” And the Biden administration’s budget request for 2024, released March 9, allocated just $1.5 million for VERITAS — down from a projected $124 million — in what some in the planetary science community have called a soft cancellation.
In an April 5 statement, The Planetary Society called on Congress to “save VERITAS” by setting a 2029 launch date. The statement was co-signed by the American Geophysical Union — the professional society that represents U.S. planetary scientists — as well as three universities involved in VERITAS: UAF, Tulane University, and Mount Holyoke College.
“Without VERITAS, the United States will miss an extraordinary opportunity to lead the vanguard of scientific exploration of Venus, including how its climate and surface changed from a habitable to uninhabitable environment,” the letter reads, warning that other organizations, including Chinese and European agencies with plans for orbiters, “may end up leading Venus exploration in the coming decades.”
NASA is still pressing forward with the Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging (DAVINCI) mission, set for a 2029 launch. But unlike VERITAS and its global view, DAVINCI’s main objective is to sample Venus’ clouds and examine terrain up close by deploying a probe that will fall through the planet’s atmosphere. ESA is also preparing a Venus orbiter called EnVision, which is tentatively set to launch in the early 2030s.