moral issue to which I alluded is more serious than I suggested. Webb, the Zero commander says:
"'You get used to it...Shooting people in the back. It gets easier.'" (p. 62)
Oh no, it shouldn't get easier. Even Ian Fleming's notoriously "licensed to kill" character found cold blooded killing increasingly difficult - and nearly got himself killed as a result.
(ii) Is space dark or full of light? Poul Anderson describes many brightly colored stars and galaxies and used phrases like "a wilderness of stars." Collyer emphasizes the darkness between the stars:
"...there was nothing but the candle-flames of stars amongst the vastness of space." (p. 39)
"Hugo stood for a moment longer, gazing out into the darkness beyond the viewscreen..." (p. 47)
(iii) Clearly the spaceships are not rockets. They do not blast off:
"The Zero hummed and he felt her rock underneath him as she lifted off the ground." (p. 39)
The crew "...used thrusters and dampers to steer the ship..." (p. 25)
Since artificial gravity has been used to colonize the Moon (see here), I deduce that ships lift and move through control of gravity fields. The sub-lieutenant looks through "...fuel inventories and tech checks..." (p. 46) Does manipulation of gravity involve the consumption of fuel? Or is fuel used for something else?
(iv) A vast interconnected computer network used to be an sf idea. Now we live with it and it is still in our sf. The Orbit civilization has a "...solarnet..." (p. 100), although presumably this has a light speed limit?