WASHINGTON — Senate appropriators want to give a small office at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, a $20 million budget increase to help launch a robotic servicing mission to an aging U.S. satellite by 2019.

Tucked away in the $18.3 billion 2016 NASA budget approved June 11 by the Senate Appropriations Committee is $150 million for Goddard’s Satellite Servicing Capabilities Office.

The office — which was founded in 1984 and engineered five astronaut repair missions to the Hubble Space Telescope in the 1990s and early 2000s — got $130 million in 2015 and $125 million in 2014, NASA spokesman Dewayne Johnson wrote in a June 17 email. The shop employs “a few dozen civil servants,” he said.

The report accompanying the Senate’s commerce, justice, science spending proposal said the so-called Restore-L Pathfinder mission should launch no later than 2019 and aim to refuel the Earth-observing Landsat 7 satellite, which has been in orbit since 1999. NASA has said the satellite likely will be switched off in 2019.

The bill, whose prospects for passage are in question, would also move the servicing office’s budget out of the International Space Station’s research budget and into an independent line within NASA’s Space Technology Mission Directorate. The bookkeeping change would give the Satellite Servicing Capabilities Office some cross-agency clout; the Space Technology Mission Directorate works on technologies that can be folded into any NASA program.

“The funds set aside for the RESTORE-L Pathfinder mission should lead to the immediate funding of efforts to formulate a rapid mission, done in partnership with and overseen by NASA’s existing satellite servicing expertise,” the Senate Appropriations commerce, justice, science subcommittee said in the report.

Sen. Barbara Mikulski (D-Md.), ranking member of the subcommittee and full committee, has been a tireless champion for the Restore project since its conception. Her support, however, has not yet gotten the mission off the ground, or even into formal planning stages.

“The Restore-L concept remains a study,” Johnson wrote in his email. “As a mission concept it has not been independently funded.”

Landsat 7 “is just a candidate” for the servicing pathfinder mission, Ben Reed, deputy project manager for the Satellite Servicing Capabilities Office, said during a June 16 press tour at Goddard. “We study many satellites. That happens to be a study case. It’s owned by the government, it’s near the end of its fuel life, so we study it.”

Other candidates, Reed said, include NASA’s Terra and Aqua satellites: low-orbiting Earth-observers that launched in 1999 and 2002, respectively.

As recently as 2014, Goddard thought a Restore mission could launch by 2017. Last year, Reed floated the 14-year-old Geostationary Operational Environmental Satellite (GOES)-12 spacecraft, which is orbiting 36,000 kilometers above the equator, as a possible servicing target. GOES-12 once kept watch on the U.S. East Coast but since 2009 has been in standby mode on orbit following a series of thruster leaks.

The White House mentioned the Restore-L Pathfinder in the 2016 budget proposal released in February but did not request a specific amount of funding for the project. The Obama administration has also been pushing to rename the Satellite Servicing Capabilities Office to In-Space Robotic Servicing.

The proposed name change reflects the White House’s desire to more closely align the office with the administration’s proposed Asteroid Redirect Mission, which will require a new robotic spacecraft to collect a small asteroid sample and send it to a lunar storage orbit for astronauts to visit in the mid-2020s. Mikulski rejected the idea when the White House trotted it out in 2014 and has rejected it again in the latest Senate-crafted NASA spending bill.

Although Restore-L Pathfinder is still in a study phase, the Satellite Servicing Capabilities Office has proved out some of the basic technology required to do the mission in a series of space- and ground-based demonstrations that began in 2011.

That was the year the office sent its Robotic Refueling Mission to ISS on the final space shuttle mission. The mission features a dummy satellite, complete with thermal blankets, fuel caps, wires and a fuel reservoir, that allows NASA to simulate a satellite servicing using the space station’s robotic arm, a set of Goddard-made servicing tools, and a fluid with roughly the same density as the satellite propellant hydrazine.

The latest Robotic Refueling Mission took place in May.

Kyle Connor contributed to this story from Greenbelt, Maryland.

Dan Leone is a SpaceNews staff writer, covering NASA, NOAA and a growing number of entrepreneurial space companies. He earned a bachelor’s degree in public communications from the American University in Washington.