2N-SING [with poss](事物的)存在期,使用期 The lifetime of a particular thing is the period of time that it lasts. (事物的)存在期,使用期
...the lifetime of a parliament. [+ of]
议会的届期
...a satellite's lifetime.
卫星的使用期
3PHRASE 终生难遇的;千载难逢的 If you describe something as the chance or experience of a lifetime, you are emphasizing that it is the best or most important chance or experience that you are ever likely to have. 终生难遇的;千载难逢的 [emphasis]
This could be not just the trip of a lifetime but the experience of a lifetime.