Sure. But they always turned out to be 'identifiable' after they studied them more carefully. I know there is a lot of stuff out there on the Internet about odd-shaped objects seen outside Gemini and Apollo space capsules, but so far as I know, the reports were simply particles of dirt, frozen water, urine and the like. You have to understand that the near-Earth environment is not clean. We ourselves have soiled it with gloves, nuts and bolts, spent rocket stages and over 6000 other objects being tracked by NORAD. 'UFOs' as Unidentified Flying Objects should be quite common. Flying Saucers should be rare-to-non existent!