midcourse

[mid-kawrs, -kohrs]

noun

the middle of a course.
Rocketry. the portion of a ballistic trajectory between the end of powered flight and the beginning of the reentry phase.
Aerospace. the portion of a space trajectory between leaving the earth's vicinity and arrival at the desired destination, as another planet.

Origin of midcourse

First recorded in 1555–65; mid- + course

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

The "Dialogues of the Damned" are an incomplete series, arrested in mid-course at No.
Sonia Between two Worlds
Stephen McKenna
Our planet, for example, is in the mid-course of its experience.
Amiel's Journal
Henri-Frdric Amiel
None, no none, could get anywhere near it; even Martin was left many yards behind in mid-course.
A Hungarian Nabob
Maurus Jkai
The interior table-land, especially towards the mid-course of the Zambesi, is intersected by lofty mountain-chains.
The Desert World
Arthur Mangin
The daughter's hand, which had just resumed the needle, stood still in mid-course with the white thread half-drawn.
The Grandissimes
George Washington Cable

1560s, from mid + course (n.).