Having a resource for accurate ready-built CAD models certainly saves time. From hardware fasteners to specific product designs, more and more suppliers are providing 3D models of their products either directly from their sites, or through community contribution sites that host supplier-certified models.
|Space Exploration Vehicle (SEV) concept|
courtesy of NASA
Currently the NASA 3D Resources site is hosting over 300 models that range from A (AcrimSAT) to Z (Z2 Spacesuit), and include the full array of manned, unmanned and satellite programs. Files are primarily available in obj format, and they are in the process of converting models to stl format for 3D printing.
Therefore, whether your interest is driven by design, curiosity or nostalgia, NASA 3D models are certainly an intriguing resource to living history.