In the early 21st century, the Teacher in Space project was revived in the private sector. The development of reusable, suborbital launch vehicles by commercial companies makes it possible for nonprofit groups to contemplate sending large numbers of teachers into space. The new Teachers in Space program began in 2005. In March 2005, Teacher in Space candidate Pam Leestma, a second-grade teacher and cousin of Space Shuttle astronaut David Leestma, completed a training flight aboard a MiG-21 operated by X-Rocket, LLC.