The approach taken in this paper is to investigate the different probabilities regarding the nature of the near-earth pass of the object designated 1991 VG. Three distinct possibilities are apparent. The first is that it was a natural asteroid, to which we assign a probability P(n), that is, Probability natural. The second is that it was a man-made spacecraft, probability P(s), or Probability spacecraft. The third is that it was an alien artifact, probability P(a), Probability artifact. If we assume that there are no other possible explanations then the three taken together and written in formula P(n) + P(s) + P(a) = 1. The scepticism of a scientist (myself included) leads one to assume that P(a) = 0, but that assumption, it will be seen, is not supported by our knowledge of 1991 VG and its discovery circumstances. I show below that these indicate both P(n) and P(s) to be small, implying that P(a) , Probability artifact, is significant.
