(CNN) -- Four hundred space shuttle employees will be laid off beginning in October, a spokesman for a National Aeronautics and Space Administration contractor told CNN on Tuesday
Jeff Carr, spokesman for United Space Alliance, NASA's primary contractor for the space shuttle, said he thinks most of the layoffs will come from volunteers, and 60 percent are to come from Florida crews.
He said notice of the layoffs has been sent to the entire corps of Space Shuttle employees.
United Space Alliance has 9,300 employees working on the space shuttle in Florida and in Houston, Texas, he said.
"The new workforce level is what's needed to support (the) shuttle through the end of flight," Carr said.
Eight shuttle missions are left in the program, which is scheduled to be completed in September 2010. A major workforce reduction is likely at that time, Carr said.
He said United Space Alliance is looking for new space-related business to offset the loss of shuttle jobs.
NASA currently is planning to start test flights for the vehicle that is to replace the shuttle in 2014, but budget constraints could push that date back.