So far, NASA has launched just one of the 15 missions recommended in the 2007 Earth science decadal survey: the Soil Moisture Active Passive, or SMAP, mission. The $915 million mission launched Jan. 31, 2015. Less than six months later, its radar failed but its radiometer continues to function.

WASHINGTON — The co-chair of the most recent Earth science decadal survey warned that NASA faces “difficult choices” between continuing current missions and starting new missions given limited funding.

At a Jan. 17 meeting of the NASA Advisory Council, Waleed Abdalati, a member of the council and former NASA chief scientist, said several factors have resulted in a budget crunch for the agency’s Earth science program and that the decadal survey’s advice for dealing with funding problems has largely been exhausted.

“It’s pretty clear that the resources are not and will not be available to fully implement the intended program,” he said. “The options are delaying planned missions or terminating extended missions.”

He identified several factors that are causing that challenge. They include supply chain and workforce problems linked to the pandemic, a fiscal year 2023 spending bill that reduced Earth science by more than $200 million from the agency’s request, and the prospect of a long-term continuing resolution in fiscal year 2024 that would lock in spending at 2023 levels.

His comments come as NASA prepares for a senior review of extended Earth science missions later this year that will examine the scientific productivity of about 15 missions, some in operation for more than 20 years, and balance that against the cost to keep them running. NASA officials have already warned that they likely will not have the funding to extend all of them.

“The senior review is not going to be an easy one this year,” said Julie Robinson, deputy director of NASA’s Earth science division, during a town hall at the Fall Meeting of the American Geophysical Union in December. “We don’t have the money in the budget to extend every mission that comes to the senior review.”

At the same time, NASA is planning to ramp up work on a series of missions called the Earth System Observatory that would implement the major “designated observables” recommended by the decadal survey. An independent review last fall, co-chaired by Abdalati along with another former NASA official, Geoff Yoder, warned of cost growth on the biggest of those missions, the Atmosphere Observing System.

“There’s a tension, though, between what do you do that is new versus what do you sustain that is already flying,” Abdalati said.

Abdalati was a co-chair of the decadal survey, released five years ago, that recommended those designated observables and other missions. Anticipating the potential for budget issues, the decadal included several “decision rules” to guide NASA. They included delaying missions or reducing the number of competed missions.

Those options, he said, have been exhausted. “NASA has exercised all of these options and the resource challenges still remain,” he said. Additional options could involve further delays of the Earth System Observatory missions or smaller competitive missions as well as terminating current missions.

Another option, he suggested, would be to accept higher risk on new missions to reduce their cost, but he warned that approach has drawbacks. “From a climate perspective, the cost of not succeeding, of taking on those additional risks, are very high, because you lose time. You don’t just lose a measurement, you lose time, much needed time.”

Abdalati said the National Academies is preparing for a midterm review of the Earth science decadal that could offer NASA additional recommendations on how to balance that report’s recommendations with current missions given available funding. “But, at the end of the day, it’s pretty clear that not everything can be done, and there is going to need to be an assessment of what does not get done now.”

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...