As an aside, the name Candidatus Desulforudis audaxviator is very interesting. The Candidatus is because it’s never been seen – its existence is inferred from isolated DNA. Desulforudis refers to its metabolism. audaxviator, according to Wikipedia,

…comes of a quotation from Jules Verne’s Journey to the Center of the Earth. The hero, Professor Lidenbrock, finds a secret inscription in Latin that reads: Descende, audax viator, et terrestre centrum attinges (Descend, bold traveller, and you will attain the center of the Earth).

In deep space, even if the organism’s metabolism is powered entirely by radioactive decay, the loss of heat would prevent metabolic activity and reproduction. Even with modern engineering, there’s no power source capable of sustaining the kinds of temperatures necessary for reproduction for millions of years, short of a full-scale nuclear reactor (see http://en.wikipedia.org/wiki/Voyager_program#Powering_down).

Saline ground waters in fractured crystalline rock at depths of 2-3 kilometers below in the surface in the Witwatersrand Basin of South Africa has been shown by IPTAI scientist to host microbial ecosystems sustained by hydrogen consumption linked to sulfate reduction. Sulfate and hydrogen in the Witwatersrand basin are continuously produced by water- rock reactions associated with radioactive decay of uranium. Radiolysis of groundwater water generates hydrogen as a primary product of disproportionation of water and generates sulfate as secondary product during reaction of hydrogen peroxide and pyrite. Based on data from sites in Canada, Finland and South Africa, deep groundwater in fractured rock represents a potential energy-rich environment for subsurface life and contains some of the highest levels of dissolved H2 ever measured in ground waters.

Umm, WHY? The news species is composed of the same chemicals as other lifeforms on earth: same nucleic acids, same amino acids, same lipids and so on. What are the chances that life evolved somewhere else in EXACTLY the same fashion as life here on earth?

What was different about this species was the genetic SEQUENCE (not the chemical composition of the hereditary material), which we would expect from a long time in isolation. No evidence for panspermia. Completely in line with standard evolutionary theory.

Does D. audaxviator use a different heritability system or something? No (if it did, that surely would have been mentioned in the article).

It descended from the same ancestors as all living things here on the surface. At some point it got isolated (by rock / continental movement, for example) and lives in a very extreme environment, that selected for a very unique and narrow phenotype.

Interesting for sure. But how does this confirm panspermia?

And really, the second quote you provided is a non sequitur of the point you are trying to make re “If life starts only on planets…”

Worse because it means that intelligent life is more likely to destroy itself?

It would seem to me that if life has to originate in comets and then migrate accidentally to a “Goldilocks” planet to develop intelligence, that might actually make the Fermi Paradox less bad.