 Although computer models suggest that a captured meteoroid would typically take some tens of millions of years before collision with a planet, there are documented viable Earthly bacterial spores that are 40 million years old that are very resistant to radiation, and others able to resume life after being dormant for 25 million years, suggesting that lithopanspermia life-transfers are possible via meteorites exceeding 1 m in size.The discovery of deep-sea ecosystems, along with advancements in the fields of astrobiology, observational astronomy and discovery of large varieties of extremophiles, opened up a new avenue in astrobiology by massively expanding the number of possible extraterrestrial habitats and possible transport of hardy microbial life through vast distances.The question of whether certain microorganisms can survive in the harsh environment of outer space has intrigued biologists since the beginning of spaceflight, and opportunities were provided to expose samples to space.