Shortly after Ryland and Rocky attempt their rather adventurous orbital insertion at the planet Adrian, they discover “Gravity still here”. 19.173 In other words, they are still experiencing acceleration, though baffled by what could be causing it. Ryland looks to the Nav console and confirms that the ship is “in a stable orbit around Adrian. Well, actually it’s ugly as heck—the apogee is 2,000 kilometers farther from the planet than perigee.” 19.174

Later, when Ryland is particularly sleep-deprived (not that this state of consciousness is uncommon for the character), he tells Rocky that he cannot sleep yet: “I will in a bit. But first I have to stabilize our orbit. Our apogee and perigee are...well, it’s not a good orbit.” 21.086

Apogee refers to the furthest point in an object’s orbit around the Earth. Perigee refers to the closest point in an object’s orbit around the Earth (“gee” coming from the Greek word for Earth).

Generally these terms are used to refer to the Moon’s orbit, though they can also be applied to artificial satellites. During one full period of the Moon’s orbit around Earth, its average perigee is around 363,300 km and its average apogee is around 405,500 km. When a full Moon occurs at perigee, we refer to this as a “supermoon”. Similarly, the most distant and nearest points in the Earth’s orbit around the Sun are called perihelion and aphelion respectively (“helion” coming from the Greek word for Sun).

It is interesting to note that Ryland settles on the terms “apogee” and “perigee” for Adrian, which is located 12 light-years away from his home planet to which those words refer.

When Ryland describes the orbit as ugly/not good, he is referring to the eccentricity, a measurement of how circular (or not) an orbit is. The visualization below shows different eccentricities (e) and the position of the perigee (purple) and apogee (green).