Answer: "Space travel is a dream of the future" is the grammatically correct sentence.
Explanation: In the given sentence, "s" of "space" will be capitalized as it is the first word of the sentence.
The word "travel" was spelled incorrectly.
The placement of the article "a" was wrong. An article must be placed before a noun or an equivalent of a noun. Thus, "a" was shifted before the word "dream" so that the sentence makes more sense.
Thus, the proofread sentence after fixing spelling, punctuation and capitalization errors is "Space travel is a dream of the future".
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