Venus in ultraviolet taken by NASA’s Pioneer-Venus Orbiter in 1979. Credit: NASA

The annual meeting of a scientific committee called the Venus Exploration Analysis Group, or VEXAG, coincided this year with Halloween. Befitting the occasion, there were both tricks and treats for scientists studying the planet Venus.

The treat was the promise of upcoming missions. Within the next decade, two NASA spacecraft, DAVINCI and VERITAS, and Europe’s EnVision, will go to Venus, studying its surface and atmosphere in unprecedented detail, ending for NASA a decades-long drought in Venus missions.

“We are going to see a type of Venus that we have never seen before,” said Paul Byrne, a planetary scientist at Washington University in St. Louis, at the meeting, thanks to instruments like high-resolution radar imagery. “We’re going to see stuff at Venus that’s going to be insane.”

The trick is that one of those missions, VERITAS, still faces an extended delay. A year ago, NASA announced it was postponing VERITAS by three years to 2031 after an independent review found institutional problems at the Jet Propulsion Laboratory that contributed to a delay in the Psyche asteroid mission. Putting VERITAS on hold, the agency explained, would ensure sufficient resources for Psyche and other high-priority missions.

The mission’s leaders are still lobbying to move up VERITAS. Sue Smrekar, VERITAS principal investigator at JPL, argued that many of the problems at the lab that prompted the delay had been resolved. A launch in late 2029, she said, was still feasible “if we get rolling in the next year.”

VERITAS, though, faces more than just issues at JPL. “It’s totally true that the budget is a mess,” she acknowledged. NASA’s planetary science program is facing severe challenges from both overall budget pressures at the agency as well as cost growth on one of its flagships, Mars Sample Return (MSR).

In September, an independent committee concluded MSR had “unrealistic” cost and schedule estimates and could cost up to $11 billion. NASA responded by convening a team to examine alternative architectures for MSR.

At an Oct. 19 meeting of the Mars Exploration Program Analysis Group (MEPAG), both NASA officials and scientists said they remained committed to MSR, citing the value of bringing back samples. MSR was endorsed by the most recent planetary science decadal survey in 2022.

That recommendation, said one of the co-chairs of the decadal survey, Philip Christensen of Arizona State University, “was not achieved lightly, and it really does represent the view of the broad planetary science community of the importance of this project.”

While MSR’s woes might be contributing to budget problems for other missions, scientists at VEXAG looked at it less with frustration than with envy. MSR is the culmination of a decades-long NASA Mars program that included a series of orbiters, landers and rovers.

Scientists who struggled for years to get missions like DAVINCI and VERITAS selected want to see a similar long-term program for Venus. At VEXAG, Byrne outlined the draft of a Venus exploration strategy that explains the importance of continued missions to Venus.

The goal of that strategy, he said, is that by the time of the next decadal survey in the early 2030s, “there is enough justification on behalf of the community and the work we’ve done to warrant the recommendation of the establishment of a program.”

The program could lead to more ambitious missions, like landers, but will also require extensive technology development to survive and operate in the planet’s dense, hot atmosphere. While Martian rovers have operated for more than a decade at a time, the lifetimes of the most robust Venus landers were measured in hours.

But just as Mars scientists backed a program that led up to the ambitious but expensive MSR, Venus scientists want a similar series of missions to help them understand that enigmatic planet. Byrne noted that the scientific rationale for a rover on Venus is just as strong as Mars rovers. “It’s just really hard to do.”

“Maybe we won’t see a Venus rover until the 2070s,” he said, “but if we don’t start talking about it now, it’ll never happen.

This article first appeared in the November 2023 issue of SpaceNews magazine.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...