mid-course
/ˌmɪdˈkɔːs/noun
1The middle of a course taken by a person or thing.
2A middle course or mode of procedure.
adjective
1Occurring or performed in the middle of a missile's course or a spacecraft's flight.
2 US. In extended use. Made, carried out, or performed during a course, project, campaign, etc.; frequently in mid-course correction.
Origin
Early 16th century; earliest use found in Gavin Douglas (c1476–1522), poet and bishop of Dunkeld. From mid + course.