Nehemiah 9:6

אַתָּה הוּא ה’ לְבַדֶּךָ את עָשִׂיתָ אֶת הַשָּׁמַיִם שְׁמֵי הַשָּׁמַיִם וְכָל צְבָאָם הָאָרֶץ וְכָל אֲשֶׁר עָלֶיהָ הַיַּמִּים וְכָל אֲשֶׁר בָּהֶם וְאַתָּה מְחַיֶּה אֶת כֻּלָּם וּצְבָא הַשָּׁמַיִם לְךָ מִשְׁתַּחֲוִים

You are G-d, You alone. You have made heaven, the heaven of heavens, with all their host, the earth and all things that are on it, the seas and all that is in them. You preserve them all and the host of heaven bow down to You.

The Metzudas David explains that “the heaven of heavens” refers to the heavens that are above the visible heavens. This might refer to what we would call “deep space,” since he also says that “their host” refers to the stars and constellations.