Wiktionary
n. A journey, by a manned or unmanned vehicle, into space for a specific reason (normally to gather scientific data)
Usage examples of "space mission".
The theory that she had been on a secret space mission - still part of popular mythology outside the USSR - could be ruled out.
When he transferred to the cosmonaut corps he was almost bored with the Newtonian predictability of each space mission.
This bomb was built for a specific deep-space mission, and it will be fitted with all sorts of safety devices to prevent detonation except on a positive command.
His had been the first deep-space mission, five Athenas to Saturn.
On that date, isn't it true that you took part in another space mission conducted by Amspace—.
That was when he volunteered for a deep space mission, determined not to return without proof of his academic prowess -- his skill as a scientist on a par with any human!