 So NASA has ordered testing of a spare thruster here on Earth. The work is being done at the space agency's White Sands test facility in New Mexico. Engineers will put one of Starliner's thrusters through its paces, simulating going to space and returning in an effort to understand the problem. NASA says these tests will take around two weeks. It will not set a return date for the astronauts flying Starliner until the testing is complete. Jeff Brumfield, NPR News.