Will NASA Kill a Pair of Critical Climate Satellites?

As Congress returns to session this month, the fate of two satellites that have become integral to climate science hangs in the balance.

The Orbiting Carbon Observatory-2 and -3, or OCO-2 and -3, have been circling the globe for years, gathering some of the best data available on carbon dioxide concentrations in the atmosphere.

They helped scientists determine that natural systems struggled in the extreme heat of 2023 and failed to pull in as much CO2 as normal. They’ve helped researchers track early indicators of agricultural drought in India, and measure climate-warming emissions coming out of coal power plants in Montana, Poland and Canada.

They are the “gold standard” for measuring the most abundant climate-warming gas in the atmosphere from space, according to NASA. Yet the space administration has proposed ending the satellites’ missions next year, part of the Trump administration’s proposed 24 percent reduction in the agency’s budget.

Across NASA, the cuts would amount to $6 billion. Nixing the two satellites would provide $16 million of that, about a quarter of a percent of the total.

“It would be a blow to science to have these missions canceled,” said Ray Nassar, a research scientist at Environment and Climate Change Canada, that country’s environmental regulatory agency, who stressed that he was not commenting on the merits of a U.S. policy proposal but only its potential impact to science. He has used OCO data to show how satellites could measure pollution from individual power plants. 

Nassar noted that it cost hundreds of millions of dollars to build and launch the satellites, “and the continual operation of them is a fraction of that cost. So to shut them off is … not really getting the full return on the initial investment to get them there.”

Congress has until the end of September to approve a budget for the next fiscal year, and bills introduced so far have proposed maintaining NASA’s science budget or enacting more modest cuts than the Trump administration is pursuing. 

The proposed end for the satellites’ missions is part of a broader attempt by the Trump administration to slash federal investments into earth and climate sciences, including at the National Oceanic and Atmospheric Administration and the National Science Foundation.

OCO-2 was launched in 2014 to measure CO2 concentrations in the atmosphere and to better understand how pollution from power plants, vehicles and other sources are offset by natural systems that absorb the climate pollutant. Its launch came after a previous attempt to launch a similar satellite failed in 2009.

OCO-3, which is attached to the International Space Station, was launched in 2019. According to NASA, it provided “for the first time, daily variations in the release and uptake of carbon dioxide by plants and trees in the major tropical rain forests of South America, Africa, and South-East Asia, the largest stores of above ground carbon on our planet.”

A 2023 senior review for operating missions determined that OCO-2 was in “excellent condition” and had enough fuel to operate until 2040. 

A NASA spokesperson pointed to the administration’s technical budget document, which says, “To align with the President’s agenda and budget priorities, OCO-2 and OCO-3, two climate missions beyond their prime mission, will close out and end in FY 2026.” The spokesperson added that “as the budget has not yet been enacted, it would be inappropriate for us to comment further at this time. As always, NASA will follow the law.”

Jack Kaye, who retired from NASA in April and served as associate director of research in the earth science division, said data from the OCO satellites has become a central piece of the global science community’s work on the carbon cycle. Kaye said it would be highly unusual to shut down a well-operating satellite.

“It’s been a long time since we’ve taken something that was working well and said, ‘Let’s not do it anymore,’” Kaye said. “And these are working well.”

While some nations and private companies maintain other satellites that measure CO2, Kaye said NASA’s satellites have a stronger emphasis on calibrating and validating the data for accuracy. He noted that scientists and officials use the data from OCO-2 and -3 across the world to make environmental policy, and that turning off the satellites would take the United States “out of the information-generating game.”

Nassar said the OCO satellites provide the most precise measurements of CO2, helping scientists better understand the cycling of carbon through the atmosphere and ecosystems.

While that work could still continue without the OCO satellites, “it’s sort of like telling someone, if you didn’t have eyes you could still hear and taste, so why do you really need your eyes?” Nassar said. “It’s taking away a tool that we’re reliant on today. It doesn’t mean we don’t know anything without it, but we would have a limited view of what’s going on.”

If Congress chooses to cut funding for the satellites, there’s a chance that some other entity, like a private company or philanthropy, could take them over. In July, NASA included the OCO-3 in a list of proposals it was soliciting, saying its funding could end and that it was “seeking a partner.”