of carbonation of epoxy and corrosion of steel anchors that held the refractory bricks in the trench in place. The damage had been exacerbated by the fact that hydrochloric acid is an exhaust by-product of the solid rocket boosters. Just as for the first 24 shuttle flights, LC-39A supported the final shuttle flights, starting with STS-117 in June 2007 and ending with the retirement of the Shuttle fleet in July 2011. Prior to the SpaceX lease agreement, the pad remained as it was when Atlantis launched on the final shuttle mission on July 8, 2011, complete with a mobile launcher platform. SpaceX Talks for use of the pad were underway between NASA and Space Florida — the State of Florida's economic development agency — as early as 2011, but no deal materialized by 2012, and NASA then pursued other options for removing the pad from the federal government inventory. By early 2013, NASA publicly announced that it would allow commercial launch providers to lease LC-39A, and followed that, in May 2013, with a formal solicitation for proposals for commercial use of the pad. There were two competing bids for the commercial use of the launch complex. SpaceX submitted a bid for exclusive use of the launch complex, while Jeff Bezos' Blue Origin submitted a bid for shared non-exclusive use of the complex, so that the launchpad would handle multiple vehicles, and costs could be shared over the long-term. One potential shared user in the Blue Origin plan was United Launch Alliance. Prior to the end of the bid period, and prior to any public announcement by NASA of the results of the process, Blue Origin filed a protest with the U.S. General Accounting Office (GAO) "over what it says is a plan by NASA to award an exclusive commercial lease to SpaceX for use of mothballed space shuttle launch pad 39A". NASA had planned to complete the bid award and have the pad transferred by October 1, 2013, but the protest "will delay any decision until the GAO reaches a decision, expected by mid-December". On December 12, 2013, the GAO denied the protest and sided with NASA, which argued that the solicitation contained no preference on the use of the facility as multi-use or single-use. "The [solicitation] document merely asks bidders to explain their reasons for selecting one approach instead of the other and how they would manage the facility".