Original sentence: In the event NASA's T-38 Talons are not in use, the STAs are used for transporting crewmembers between major sites, namely from Johnson Space Center in Houston to Kennedy Space Center in Cape Canaveral, Florida
Edited sentence: In the event NASA's T-38 Talons are not available, the STAs are used for transporting crewmembers between major sites, namely from Johnson Space Center in Houston to Kennedy Space Center in Cape Canaveral, Florida