WASHINGTON — A NASA decision to replace a carbon-observing satellite lost in a February launch mishap could come at the expense of other Earth-observing missions entering development, according to Ed Weiler, the U.S. space agency’s associate administrator for science.

Speaking during a Sept. 28 American Institute of Aeronautics and Astronautics luncheon here, Weiler said officials in Congress and the White House are working on a plan to replace the capabilities lost when NASA’s Orbiting Carbon Observatory (OCO) was destroyed during a failed Feb. 24 launch attempt aboard a Taurus XL rocket. Weiler said a decision is expected in the coming weeks. But he cautioned that any plans to replace the $209 million mission, designed to make precise measurements of atmospheric carbon dioxide, could delay other projects in the pipeline, including the Soil Moisture Active Passive (SMAP) mission and ICESAT-2, which is a follow-on to NASA’s Ice, Cloud, and land Elevation Satellite that was launched in 2003.

“Our statement is if the country really wants to do another OCO, they’ve got to understand that with a fixed budget [in NASA’s Earth Science Division], it’s a choice between OK, we can do OCO right now, but you know that SMAP, that soil moisture thing you’re really worried about in the southwest desert? And that thing called ICESAT that watches the ice disappear? Those have to get delayed further,” Weiler said.

Although both missions are still under study, SMAP is tenatively slated to launch in 2013 followed by ICESAT-2 in 2015, according to the NASA Science Web site.

The 441-kilogram OCO spacecraft was built exclusively to map carbon dioxide levels on Earth. The satellite carried a single three-channel spectrometer to make its detailed measurements and was slated to launch into a near-polar, sun-synchronous orbit. After eight years of development, OCO’s loss was a blow to global climate research. Climate scientists expected OCO to take the lead in an international collection of weather monitoring spacecraft known as the A-Train, an ad hoc constellation orbiting the Earth to build a 3-D picture of the planet’s weather and climate change, as well as understanding human contributions to global warming.

“There are a lot of people working the OCO issue right now,” Weiler said, including officials in Congress, the White House Office of Management and Budget, and the Office of Science and Technology Policy. “We’re hoping for final resolution in the next two to four weeks.”

NASA has a number of options for recovering the capabilities lost when OCO crashed into the ocean near Antarctica earlier this year. Among the options under consideration, according to a report accompanying the House version of the 2010 Commerce, Justice, Science Appropriations bill, are: continuing to operate the Atmospheric Infrared Sounder aboard the Aqua satellite; accelerate development of an OCO follow-on spacecraft known as ASCENDS, which is currently targeted for a 2013 launch; or building and flying another OCO.

Both OCO and its launch vehicle were built by Dulles, Va.-based Orbital Sciences Corp.

Weiler said NASA’s Earth Science Division, led by Michael Freilich, has suffered a lack of funding for “many, many years” and that the division has a number of projects in the queue ahead of OCO. He cited several “foundational missions” that must be funded because they underpin the latest 10-year plan for space-based Earth observation put forward by the National Academy of Sciences. These missions include the next Landsat Data Continuity Mission, also known as Landsat 8, and NASA’s Global Precipitation Measurement mission, a next-generation Earth science effort that includes a core spacecraft scheduled for launch in July 2013 and a low-inclination satellite scheduled for launch in November 2014. In addition, NASA’s Glory climate-monitoring satellite and the National Polar-orbiting Environmental Satellite System Preparatory Project are also in the queue.

“We’ve got to finish those, and they cost X, and on top of that you’ve got the decadal from the National Academy of Science, so you must do these, and of course all the costs were under-costed,” he said. “But on top of that you’ve got things you didn’t really budget for, because you don’t budget or plan for things going into the [ocean near Antarctica].”

Weiler said the choice to replace OCO and risk delaying other missions is not his to make.

“That’s a choice that’s above my pay-grade, Mike’s pay-grade, even [NASA Administrator Charles Bolden’s] pay-grade,” he said. “You’ve got a billion-, or a billion-and-a-half-dollar program, and you can do a lot with that, but you can’t do everything.”