Two leases composing the National Science Foundation headquarters in Ballston expire in 2013, prompting frenzied interest from local developers in search of tenants.

The NSF is an independent federal agency that promotes science through research and education programs. On behalf of the NSF, the General Services Administration requested congressional authority to lease up to 690,000 square feet in contiguous space for the agency in Northern Virginia.

The NSF is housed at 4121 and 4201 Wilson Blvd. in Arlington, but its leases expire in April and December of 2013. The NSF is an attractive tenant for landlords not only because it currently employs 1,500 full-time staff members, but also because it draws more than 60,000 visitors every year.

“They would seem to have a good amount of options, potential sites, in Northern Virginia with access to Metro,” said Art Turowski, a former GSA official who monitors federal leasing as a broker for Jones Lang LaSalle. Turowski said that the price per square foot requested by the GSA, $38, was high enough that developers in Arlington, Tysons Corner and Alexandria planning to erect new buildings were all likely to compete for NSF.

First, however, the search for space has to be approved by the congressional panels that oversee GSA and public buildings. The agency’s search request was submitted last December and neither the House nor Senate committee responsible for approving space has acted.

Those panels have been occupied with cost-saving measures and investigating a $557 million lease for downtown Washington offices signed by the Securities and Exchange Commission. The lease prompted two House hearings and may lead to prosecution by the Justice Department.

No timetable for the request has been set. Justin Harclerode, spokesman for U.S. Rep. John L. Mica (R-Fla.), who chairs the Transportation and Infrastructure Committee, said the committee was reviewing a number of prospective uses but did not have a firm time line for consideration of the NSF request.

Turowski called the congressional delays for considering the NSF request “unusual but not unheard of.” He said there was still time for the GSA to receive a wide array of responses from commercial landlords.