Complex sentence: The MSZ-006A1 (MSK-006) Ζ Plus A1 was the first Ζ Plus unit created and was designed to operate mainly in Earth's atmosphere.
Split into simpler sentences: The MSZ-006A1 (MSK-006) Ζ Plus A1 was the first Ζ Plus unit created. The Ζ Plus A1 was designed to operate mainly in Earth's atmosphere.