YOU SAID:

I would take a one way trip to mars

INTO JAPANESE

私は火星への片道旅に行きます

BACK INTO ENGLISH

I will go to a one way trip to Mars

INTO JAPANESE

私は火星への一方通行に行きます

BACK INTO ENGLISH

I am going to one way to Mars

INTO JAPANESE

私は火星への片道に行く

BACK INTO ENGLISH

I will go one way to Mars

INTO JAPANESE

私は火星へ向かうだろう

BACK INTO ENGLISH

I will head to Mars

INTO JAPANESE

私は火星に向かうだろう

BACK INTO ENGLISH

I will head to Mars