Learn Italian: Tra dieci anni esploreremo lo spazio. - In ten years, we will explore space.

This is the special rule for regular -are verbs in the future tense! For a verb like esplorare, the characteristic a changes to an e before adding the future endings. So it becomes esploreremo, never "esploraremo".

Why use tra for "in"?

When talking about an amount of time that will pass before a future event (like "in ten years"), Italian uses tra or fra. You don't use in for this kind of future time expression.

Why is there an article before spazio when the English translation is just "space"?

In Italian, broad concepts and general nouns almost always require a definite article, whereas English often leaves it out. Since spazio starts with "s" plus a consonant, it takes the article lo.

Why isn't the word noi (we) included in the sentence?

Subject pronouns like noi are usually dropped in Italian because the verb ending already tells you who is doing the action. The -emo ending in esploreremo can only mean "we".