WASHINGTON — NASA is overhauling its Landsat acquisition strategy to appease one of its key supporters in the U.S. Senate. But the U.S. space agency is no closer to moving out on development of a new land-imaging satellite than it was two months ago when Sen. Barbara Mikulski (D-Md.) first objected to the fixed-price approach the agency had intended to take and asked NASA to halt the procurement.

NASA, which manages and funds the development of Landsat satellites on behalf of the U.S. Geological Survey, is under pressure from Landsat’s myriad government, academic and private-sector users to field a replacement for the old and ailing Landsat 5 and Landsat 7 spacecraft by 2011. NASA had been expected to release a draft request for proposals for a so-called Landsat Data Continuity Mission (LDCM) this fall , but those plans were thrown for a loop when Mikulski threatened to withhold funding unless the agency abandoned its plan to award a single fixed-price contract for the spacecraft and instrument.

Mikulski raised her objections in report language accompanying the Commerce, Justice, Science spending bill the Senate Appropriations Committee approved July 13. Mikulski told Space News in a statement at the time that she favored a more customary acquisition approach for the next Landsat, one that “fully competed individual segments with NASA serving as the project integrator.”

While a companion spending bill already approved by the U.S. House of Representatives contained no such Landsat provision, NASA opted to modify its acquisition approach rather than get into a fight with Mikulski, an influential NASA supporter who is championing a $1 billion emergency supplemental the agency sorely needs.

Government and industry sources said NASA has agreed in principle to abandon the fixed-price approach it had been pursuing, procure the spacecraft bus and instrument separately, and give the agency’s Greenbelt, Md.-based Goddard Space Flight Center a central role in the project. Mikulski, these sources said, is still waiting for NASA to communicate the details of its new LDCM acquisition approach before lifting her objections.

NASA Administrator Mike Griffin told Goddard personnel Sept. 12 that the field center was being given the “systems integration responsibility for the Landsat Data Continuity Mission.” He made the announcement during a wide-ranging address meant to allay worries about his administration’s stewardship of the agency’s science portfolio.

Aside from Griffin’s brief remark at Goddard, NASA officials remain reticent to talk about the LDCM procurement until the agency reaches an agreement with Mikulski on a new approach.

Providing NASA’s official comment on the matter, Ted Hammer, acting associate flight program director for the Earth Science Division of the agency’s Science Mission Directorate, said in a Sept. 20 written statement prepared in response to questions from Space News that “NASA Headquarters is still reviewing the Landsat Data Continuity Mission procurement process.”

Other NASA officials familiar with the matter, speaking on the condition of anonymity, said NASA is not willing to risk alienating Mikulski over LDCM and is trying to finalize a procurement approach that meets her approval.

While NASA is willing to procure the bus and instrument separately, these officials said, the agency has not finalized such details as the role industry will play in the instrument development and whether to hold an open competition for the bus or select one from a Goddard’s so-called Rapid catalog of pre-qualified bus designs.

The Rapid catalog, established to speed spacecraft procurement, includes pre-negotiated bus offerings from Boulder, Colo.-based Ball Aerospace, EADS Astrium, Dulles, Va.-based Orbital Sciences Corp., General Dynamics’ Gilbert, Ariz.-based Spectrum Astro division, Europe’s EADS Astrium and the United Kingdon’s Surrey Satellite Technology Ltd.

Mikulski spokeswoman Melissa Schwartz declined to comment on the LDCM matter beyond saying that the senator “is waiting for NASA to communicate their plan.”