Now that it has completed preparing retired space shuttle orbiters Endeavour and Atlantis for museum display, former shuttle operator United Space Alliance (USA) plans to lay off 349 workers this holiday season, according to a NASA email.

“This reduction is due to the completion of work relating to the transfer of Space Shuttle Orbiters Endeavour and Atlantis,” Richard Irving, a NASA legislative affairs specialist, wrote in an Oct. 3 email to congressional staff. “The timing of this reduction is best from the contractor’s perspective to complete their Space Shuttle Program activities.”

According to Irving’s email, a copy of which was obtained by Space News, USA will lay off 315 workers in Florida and 34 in Texas. Layoffs will take place Dec. 7 and Jan. 4.

USA, a Boeing-Lockheed Martin joint venture, was established 17 years ago to operate the space shuttle fleet for NASA. As recently as 2005, the Houston-based company employed 11,000 people. By July, that number had fallen to about 2,500, according to the company.

The space shuttle program flew its final mission in July 2011. Lockheed Martin publicly acknowledged USA’s impending dissolution for the first time in July during a quarterly earnings call with analysts and investors.