Is this panspermia mechanism feasible?
The theory is staggeringly improbable. However, so is life. The probability of life emerging from non-life is the basis of the misguided idea of intelligent design (a thinly veiled repackaging of creationism). Bear with me: the probability of life on Earth is 1. It is here, and this is the only observation of Earth we have. But the thought of complex life appearing out of some molecular soup by chance (abiogenesis) is also staggeringly improbable. But as I said, life is here. How did it get here? There are only three possibilities: Abiogenesis, divine creation, or from panspermia (which kicks the can down the road, because it had to have begun somewhere). God is no explanation at all, because even a mystical imaginary creator would have needed some mechanism besides waving a finger. So in terms of probability, both abiogenesis and panspermia would be astronomically improbable, but since life is here (probability of life is 1), then one of these two is the source of it. We have no hard evidence to choose between them.