Boeing on Friday said it was replacing the head of its defence, space and security unit following issues with the Starliner spacecraft and armaments projects. Ted Colbert will leave the aircraft manufacturer effective immediately, new Boeing boss Kelly Ortberg announced in an email to employees. Steve Parker, who was previously responsible for operations, is to take over as acting head of the division. The Boeing-produced Starliner has left two astronauts stranded on the International Space Station (ISS) for months following numerous technical problems with the partially reusable spacecraft. T…