Complex sentence: The Boeing CCDev capsule is a spacecraft design proposed by Boeing in collaboration with Bigelow Aerospace which would be similar to a lighter, more basic version of Orion, a spacecraft being built for NASA by Lockheed Martin.
Split into simpler sentences: The Boeing CCDev capsule is a spacecraft design proposed by Boeing in collaboration with Bigelow Aerospace. Outwardly it would look much like the Orion, a spacecraft being built for NASA by Lockheed Martin.