The Greek in Luke 9:51 that is translated as “when the days drew near for him to be taken up” or similar in English is translated in the German New Testament translation by Berger / Nord (publ. 1999) with als Jesu Lebenszeit zu Ende ging or “as Jesus’ lifetime came towards an end.”

They explain (p. 465): “The Greek word analempsis only occurs in the Bible right here. It is usually translated as ‘ascension, but it can also mean ‘end of life, death.’ We prefer this possible meaning because the focus here is not on the particular manner of Jesus’ departure after the resurrection, but on his end in Jerusalem (see esp. 13:32).