Artist’s illustration of NASA’s GeoCarb mission, which will map concentrations of key carbon gases above the Americas from geostationary orbit. ( Credit: Lockheed Martin, University of Oklahoma)

WASHINGTON — NASA has canceled a greenhouse gas monitoring mission once intended to fly as a commercial hosted payload after the mission lost its ride to orbit and suffered severe cost overruns.

NASA announced Nov. 29 it was canceling GeoCarb, a mission the agency selected in 2016 to monitor carbon dioxide, carbon monoxide and methane concentrations in the atmosphere over most of North and South America. GeoCarb was part of the Earth Ventures line of small Earth science missions with an original cost cap of about $170 million.

GeoCarb was originally designed to fly as a hosted payload on a commercial geostationary communications satellite. When GeoCarb passed its confirmation review at the end of 2019, NASA planned to work with SES Government Solutions, the subsidiary of satellite operator SES that works with U.S. government customers, to find a suitable host for GeoCarb that would provide coverage over the Americas. At the time, NASA expected GeoCarb to be ready for launch in 2022.

In February, though, NASA announced it was no longer pursuing a hosted payload opportunity for GeoCarb. The agency said that market research showed no suitable hosted payload opportunities for the instrument through the end of 2024. Instead, NASA had started a new effort, called the GeoCarb Access to Space (GCATS) project, to procure a spacecraft and launch for the payload.

However, on Sept. 20 NASA disclosed in a procurement filing that it was canceling the request for proposal for GCATS, but did not a give a reason. NASA spokesperson Tylar Greene later said that NASA elected not to award a contract for GCATS “due to adjustments in the mission timeline and the instrument delivery date.”

In NASA’s announcement, the agency cited technical concerns with the mission as well as cost performance and the availability of other sources of greenhouse gas monitoring data as reasons for canceling GeoCarb. The agency said that the estimated lifecycle cost of the mission had grown to more than $600 million, and it had spent $173 million on GeoCarb to date.

“Decisions like this are difficult, but NASA is dedicated to making careful choices with the resources provided by the people of the United States,” Thomas Zurbuchen, NASA associate administrator for science, said in the statement announcing the cancellation. “We look forward to accomplishing our commitment to state-of-the-art climate observation in a more efficient and cost-effective way.”

That includes extending operations of the Orbiting Carbon Observatory 3 instrument on the International Space Station, performing more airborne observations and obtaining data from international and commercial partners. In September, NASA awarded a contract to Canadian company GHGSat, which operates several satellites that collect greenhouse gas data, as part of the agency’s Commercial Smallsat Data Acquisition program.

NASA said it will also prioritize a greenhouse gas mission as the first in its new Earth System Explorers line of competed Earth science missions, a recommendation of the Earth science decadal survey. NASA plans to issue a formal announcement of opportunity for that first mission in March 2023, with several proposals selected for concept studies in early 2024 and a final selection in mid-2025.

“We are committed to making key methane and carbon dioxide observations, integrating them with measurements collected by other national, international, and private sector missions, and making actionable information available to communities and organizations who need it to inform their decisions,” Karen St. Germain, NASA Earth science division director, said in the GeoCarb cancellation statement.

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...