Outer Space: "Deep Heaven" Or "A Hell"

Ransom en route to Mars experiences space as filled with a life-giving radiance whereas Haertel on the same journey knows that cosmic radiation is lethal. Later, Ransom experiences “trans-sensuous life” while approaching Venus in an angelically propelled coffin whereas Haertel’s successor, Garrard, endures psychophysical “pseudo-death” while enclosed in the rigid, monotonous environment of an interstellar spaceship.^{14, 15}
-copied from here.

I quote this comparison of CS Lewis' soft sf with James Blish's hard sf because, even while writing fantasy, Poul Anderson remains "hard." After listing vacuum, ultraviolet, X rays, particle radiation, temperature extremes, Steve Matuchek remarks:

"'The Fair Folk themselves had to flee the sun. For us humans, raw space is a hell. The alien demons felt right at home...."
-Poul Anderson, Operation Luna (New York, 2000), p. 272. 

Ransom, traveling through what he now regards not as cold, dead "Space" but as "...the heavens which declared the glory -" approvingly quotes Milton:

"happy climes that ly
"Where day never shuts his eye
"Up in the broad fields of the sky."
-CS Lewis, Out Of The Silent Planet (London, 1963), p. 35. 

Other inhabitants of the Solar System speak of "Deep Heaven" (CS Lewis, Voyage To Venus, London, 1978, p. 5) and Ransom, when he has returned to Earth, wants:

"'...a change-over from the conception of Space to the conception of Heaven...'" (Out Of The Silent Planet, p. 180) 

But Blish and Anderson are right that that "Heaven" would instantly kill any Terrestrial organism - and Anderson's Steve Matuchek calls it "...a hell."