Boeing said Friday the head of the company’s troubled defense, space and security unit is leaving the planemaker effective immediately.New Boeing CEO Kelly Ortberg in his first significant move since taking over in August, said Ted Colbert would be leaving and Steve Parker, the unit’s chief operating officer, would assume Colbert’s responsibilities until a replacement is named at a later date.Boeing’s space business has suffered setbacks, notably NASA’s recent decision to send Boeing’s Starliner capsule hom ...