WASHINGTON — Space Exploration Technologies Corp. (SpaceX) and United Launch Alliance (ULA) are probing NASA for details about using space shuttle launch infrastructure at the Kennedy Space Center in Florida, a senior agency official said.

“NASA has responded to one request by SpaceX and is in the process of responding to a second data/information request,” Bill Hill, NASA associate administrator for space shuttle operations, said in a March 13 statement.

SpaceX is interested in Launch Complex 39A, from which the final shuttle missions launched. The pad was also to be the launch site for the Ares rockets NASA was developing under the canceled Constellation program.

Pad 39A “is one of the options we are considering for both Falcon 9 and Falcon Heavy launches, but it depends on being awarded more launches from NASA,” SpaceX spokeswoman Kirstin Grantham said.

Hill also said NASA has received requests for information and data about Pad 39A from “other potential commercial users.”

United Launch Alliance, the Denver-based Boeing and Lockheed Martin joint venture, is the only other U.S. launch provider with rockets big enough to require use of the space shuttle facilities.

“We have been in discussions with NASA about using former space shuttle infrastructure, and those discussions are ongoing,” ULA spokeswoman Jessica Rye told Space News March 12. She declined to provide details about either ULA’s queries to NASA or the agency’s response.

Neither SpaceX nor ULA has yet reached any agreement with NASA concerning Pad 39A, the companies said.

NASA has been trying to find alternate uses for old shuttle support infrastructure at Kennedy Space Center since before the space shuttle flew its last mission last summer. The planned Space Launch System, a heavy-lift rocket NASA is building for future deep-space missions, would launch from Pad 39A, but NASA wants the site to support multiple customers.

The agency has already found a taker for at least one idled shuttle facility.

In November, NASA announced it had leased a former shuttle hangar, Orbiter Processing Hangar Bay 3, to Space Florida, the state’s aerospace economic development agency. Space Florida sublet the facility to Boeing, which intends to use the space to build and test its CST-100 space capsule.

Boeing is pitching the vehicle, along with an Atlas 5 rocket, as a commercially operated crew transportation system on which NASA could eventually buy seats for astronauts.

Boeing and SpaceX are competing for continued funding under NASA’s Commercial Crew Program, which aims to subsidize development of at least one fully operational, privately owned astronaut taxi system by 2017. ULA is expected to be the launch provider for all Commercial Crew Program entrants except for SpaceX, which builds its own rockets.

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.