"ultimate mission" is a correct and usable phrase in written English.
It is often used to describe a deeply important or final goal or objective. Example: Fighting for justice and equality for all has always been my ultimate mission in life.
What is the ultimate mission?
Their ultimate mission, however, has yet to begin.
But his ultimate mission is simple: "Make every day of summer great for every kid".
She says she diluted the bleach, blistered her throat and made herself sick, but failed in her ultimate mission.
Thrun's ultimate mission is a virtual university in which the best professors broadcast their lectures to tens of thousands of students.
But the military campaign has been dogged by friction over its ultimate mission, and which of the disparate countries involved should command the operation.
Operations were prolonged through 2024 to help give NASA a platform from which to run its near-Earth preparatory missions leading up to the ultimate manned mission to Mars.
"The ultimate goals or mission of the S.E.C. and the M.M.S. are different, but the information reported to each should be the same".
Having campaigned in 2000 against the Clinton administration's policy of "nation building" (that is, using American soldiers to rebuild broken societies and not just to invade, make a mess and then leave without cleaning it up), he now handsomely concedes that "Afghanistan was the ultimate nation-building mission".
While some military experts argue that the United States should create special peacekeeping units, the military counters that all of its forces have to be prepared for the ultimate war-fighting mission, since operations like those in Kosovo, initially at least, involve the dangerous task of separating warring factions and can spiral back into all-out combat.
In World Cup terms, Carter is the ultimate man on a mission.
