An object in this meaning is the same thing as an objective[?] or task[?]. It comes from old project terminology and refers to the act of actually performing something according to a plan, or rather "according to a project" (the word "project" used to mean "plan").
... Raleigh, (1554?-1618), English explorer
James Clark Ross, (1800-1862), Explorer
S
Robert Falcon Scott, (1868-1912), reached the South Pole less than one month after ...