UPDATED Dec. 16, 11:12 a.m. EDT

WASHINGTON — Capping off a summer of controversy that pitted two of the most prominent “new space” companies against one another, NASA announced Dec. 13 it is negotiating with Space Exploration Technologies Corp. (SpaceX) on a lease of Launch Complex 39A, a mothballed space shuttle launch pad at the Kennedy Space Center in Florida.

NASA announced its decision in a press release a day after the U.S. Government Accountability Office (GAO) denied a protest from Kent, Wash.-based Blue Origin, which had challenged the fairness of NASA’s method for choosing a lessee and delayed the start of negotiations between the agency and its preferred tenant by about three months.

Elon Musk, founder and chief executive of Hawthorne, Calif.-based SpaceX, has said Pad 39A could be used for either the company’s flagship Falcon 9 v1.1 rocket, or the Falcon Heavy booster it is developing.

SpaceX plans to use these rockets for both government and commercial launches, but “use [of] Pad 39A would be dedicated to national civil space needs,” Musk wrote in a Sept. 29 email.

“SpaceX is pleased to have been selected by NASA to enter into final negotiations for the use and operation of the historic Launch Complex 39A at Kennedy Space Center,” SpaceX spokeswoman Emily Shanklin wrote in an email. “As previously stated, SpaceX will gladly accommodate other commercial providers interested in using launch complex 39A for NASA human-rated orbital spaceflight.”

“We hope that NASA will preserve options to make this national asset available for multiple commercial users,” Robert Meyerson, president and program manager of Blue Origin, wrote in an email.

Blue Origin could again appeal to the GAO, now that the competition to lease the pad has all but wrapped up. GAO, in a 12-page decision released Dec. 12, asserted its jurisdiction over the lease competition by disagreeing with NASA’s assertion that the plan to lease Pad 39A did not amount to a procurement.

SpaceX had been at loggerheads with Blue Origin about leasing Pad 39A for months. SpaceX wanted exclusive use of the pad, while Blue Origin — whose case was supported by its business partner United Launch Alliance — wanted to make the pad a multiuser facility.

According GAO’s Dec. 12 decision, Blue Origin claimed a proposal to turn the pad into a multiuser facility should carry more weight with NASA selection officials because it better fulfilled the agency’s desire, expressed in a May 23 solicitation, to make “fullest commercial use of LC-39A.”

Blue Origin also alleged that NASA intended to award a lease based on factors other than those enumerated in the solicitation after NASA Administrator Charles Bolden said publicly that Launch Complex 39B, another old shuttle launch pad, could be adapted for multiple users. That, the company argued, amounted to a bias in favor of a single-user proposal for 39A, according to GAO’s decision document.

Blue Origin registered these concerns in a letter to NASA. That drew an Aug. 23 reply in which the agency said the solicitation expressed no preference for either a single- or multiuser approach. This answer was not good enough for Blue Origin, which then appealed to GAO.

GAO ultimately agreed with NASA and denied the protest. The agency’s solicitation, GAO decided, allowed for either single- or multiuser concepts.

Pad 39A costs the agency about $1.2 million a year to maintain in a mothballed state. NASA said this summer it wanted to get a lease signed before Oct. 1. If no lessee could be found, NASA told GAO inspectors, the agency would have been willing to let the pad — from which the Apollo 11 Moon mission blasted off — “rust to the ground.”

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.