Looking for the name of the author of a series of short novels (at least two in the series) where spacecraft engines are concentric rings (some sort of reactionless drive?) that gave off a glow when operating.
In one book, there is a small ship going to the Moon to rescue stranded astronauts. The rescue ship gets there faster by adding solid rockets to the ship to allow them to decelerate harder, thereby allowing longer acceleration phase. In the other book, it’s a larger ship going to Mars. I think “Moon” and “Mars” might have been in the titles.
I think these date from the mid 1950s to early 1960s. Don’t remember any characters, other than that these were juveniles, so I think the viewpoint character was a teenage apprentice. Library bindings, so no cover information.
I think they were part of a larger series about exploring the solar system that I did not read. I thought at first it might be Donald Wollheim, but with a closer look, I don’t think so.