Learn French: Une mission humaine ira sur Mars l'année prochaine. - A human mission will go to Mars next year.

ira is the future tense of the verb aller (to go). Aller is highly irregular, so it doesn't use its full infinitive as the future stem. Instead, it uses the special stem ir-. Because the subject Une mission acts as an elle (she/it), we add the standard future ending -a to get ira (will go).

Why do we use sur (on) for Mars instead of à (to)?

While we say going "to" a planet in English, in French you use the preposition sur (on) for planets: sur Mars, sur la Terre, sur Vénus. You can imagine it as traveling to land on the surface of the planet.

Why do the adjectives humaine and prochaine come after their nouns?

In French, most adjectives are placed right after the noun they describe, just like mission humaine and année prochaine. Only a specific group of very common, short adjectives (describing Beauty, Age, Goodness, or Size) are placed before the noun.

Why do humaine and prochaine both end in an extra -e?