WASHINGTON — NASA scientists are intensifying their focus on hosted payload opportunities, bulking up agency databases of upcoming satellites with capacity to spare and exploring concepts for common interfaces that would allow easy integration of science instruments with non-NASA satellites.

Most recently, NASA’s Langley Research Center in Hampton, Va., announced it is looking for spare payload capacity aboard spacecraft launching to geostationary orbit between 2013 and 2023. Geostationary orbit is the destination of most commercial communications satellites. The same request for information sought input from academia and industry about building what NASA calls a “common instrument interface” for integrating agency payloads with geostationary satellites. NASA already maintains a similar database for hosted payload opportunities in low Earth orbit, and has conducted two rounds of talks with industry about common instrument interfaces for low Earth orbit satellites. Responses to the latest request, released April 6, are due May 11.

NASA is looking closer at hosted payloads in geostationary orbit as a means of supporting Earth Venture Instruments missions. For these missions, a subset of the Earth Science Division’s Venture-class series of small- to medium-sized science missions, teams may propose a single science instrument for which NASA will secure a place on a spacecraft and a launch opportunity. For most NASA science missions, teams must propose an end-to-end mission concept, including a spacecraft and launch arrangements.

“The idea was, every year starting this year, [NASA] will solicit for instruments of opportunity and we’re going to build up a stable full of instruments that are looking for rides,” Doreen Neil, a senior research scientist at NASA Langley, told Space News in an April 10 phone interview. “We’ll probably get 30 instruments under that solicitation, and they won’t be selected probably until the end of the calendar year.”

Proposals for Earth Venture Instruments are due May 9. NASA is likely to pick only a single instrument, Neil said.

Michael Freilich, director of NASA’s Earth Science Division, told Space News April 6 that proposers had been given “the widest possible flexibility” to pitch hosted payload concepts in response to the Earth Venture Instruments solicitation.

Earth Science Venture-class missions are small- to medium-sized projects led by a single principal investigator. Congress approved $62.1 million for Venture-class missions in 2012, and the White House is seeking $104.8 million for 2013.

Through the Earth Venture Instruments program, NASA is hoping to establish a pipeline of science instruments that could be launched on non-NASA satellites as hosted payloads. Some of these instruments could be used to achieve the science objectives of the Geostationary Coastal and Air Pollution Events (Geo-CAPE). That mission was a priority laid out by the Earth science community in the 2007 decadal survey, the first 10-year roadmap for NASA Earth science projects.

Geo-CAPE was supposed to launch in 2016. NASA wanted to build and launch its own satellite, which would have carried three instruments to geostationary orbit. NASA initially estimated the satellite would cost $550 million to build and launch. The price tag has since swollen to $1.5 billion, Steve Volz, associate director of flight programs in NASA’s Earth Science Division, said at a NASA Advisory Council meeting this year.

“We cannot afford a geosynchronous bird on our own and launch that,” Volz said at the March meeting.

Meanwhile, other parts of NASA are also exploring hosted payload opportunities. NASA’s Space Technology Program has made the most progress, having already decided to fly two technology demonstrations aboard a pair of commercial geostationary satellites.

NASA has not selected the spacecraft that will host these payloads, but the agency has said that Space Systems/Loral of Palo Alto, Calif., will host one of the payloads: the Laser Communications Relay Demonstration. That 175-kilogram instrument will hitch a ride to space no earlier than 2016.

A proposed Explorer-class mission of opportunity called Global-scale Observations of the Limb and Disk (GOLD) seeks to place an ultraviolet imaging spectrograph aboard a yet-to-be-identified commercial communications satellite to observe the Earth’s thermosphere and ionosphere from geostationary orbit. Besides providing Earth observation data to complement other NASA science missions — the Solar Dynamics Observatory is one identified by the GOLD project team — the GOLD mission would also serve as a pathfinder mission for using commercial geostationary satellites as platforms for NASA science instruments.

NASA is expected to make an award for the next Explorer-class missions in 2013. The first flight opportunity for winning proposals is 2016.

Even NASA’s Astrophysics Division is curious about hosted payload opportunities, the acting head of that division said.

“I’ve had people [from industry] ask the question, ‘Can’t you use our surplus capacity?’ From an astrophysics point of view, that’s a really hard nut to crack,” Michael Moore, acting director of NASA’s Astrophysics Division, said at an April meeting of the National Academy of Sciences’ Space Studies Board.

Nevertheless, Moore said he was “intrigued” about the possibility of hosting astrophysics instruments on commercial satellites and suggested that astrophysicists at least discuss the possibility in “future decadal surveys.”

Most commercial satellites, even those built by U.S. companies, are launched by non-U.S. rockets. NASA, however, is required by the U.S. Space Transportation Policy of 2010 to favor domestic vehicles when choosing a launcher for its space-bound payloads.

To get a NASA payload on a foreign rocket, the agency has to secure permission from John Holdren, the director of the White House Office of Science and Technology Policy.

“Use of foreign vehicles is constrained by the space policy,” Volz said at the NASA Advisory Council meeting in March. But “hosted payloads is the avenue to make those [foreign launch vehicles] work.”

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.