Right after sunset I was in my backyard with my 4 yr-old grandson filming the many dragon flies flying above our house. I could not really capture them, but as I was trying, my eyes caught sight of a very bright object in the NNW sky ABOUT 50 degrees up, and as bright as the planet Venus at dusk (which we happened to also see), and about as 'large' from where I stood, too. It was moving faster than an airplane, so I thought it was a meteorite, but its brilliance was sun reflection, not fire. At one point it went 'dark' and I could no longer see, but not long afterwards it was visible again, and much farther along on its trajectory but much fainter too. As I was filming (sadly not in that direction) I said to my grandson "What was that ...?" That is why I can be sure of the time when I saw it.As it traveled faster than a plane, I thought it might have been the space station, but checking up on its course, I noticed it was not in my area during that day and time.The object did not veer off its trajectory. I lost sight of it because it became too small/faint as it gained distance.I felt excited, and also annoyed and frustrated because I could not identify it. I mused to my grandson that it could be an alien spaceship, but that worried him some. When I told him I wanted to get binoculars to see the object better, he was uncomfortable to let me go inside, so I didn't, and stayed with him and watched the object until it was no longer visible.He later asked me if space aliens are real and I answered that I don't know, but that I have never seen one.