How long is the life cycle of sperm?

Panspermia per se does not remove the need for life to originate somewhere, but does extend the time frame and environments available. Similarly, it does not necessarily suggest that life originated only once and subsequently spread through the entire Universe, but instead that once started it may be able to spread to other environments suitable for replication. (In the strongest version of panspermia, life never originated, but always existed — this axiom would require amending the big bang theory.) The mechanisms proposed for interstellar panspermia are hypothetical and currently unproven. Interplanetary transfer of material is well documented, as evidenced by meteorites of Martian origin found on Earth. However, claims that these carry evidence of extraterrestrial lifeforms — let alone viable dormant lifeforms — have either been proven unfounded as a result of terrestrial contamination, misinterpretation, or hoaxing; or are currently hotly disputed. Interestingly, space probes may also be a viable transport mechanism for interplanetary panspermia in our solar system (or even beyond) especially as terrestrial bacteria were shown to have survived in a dormant state on the Moon. Since then, however, NASA has implemented strict abiotic procedures to avoid planetary contamination.