Five satellites is a thin constellation by terrestrial standards. GPS operates 31 and Galileo 28 [5][6], 59 between them [2], and a phone receiver simply picks whatever subset gives it usable geometry. The lunar service begins with one satellite and grows to five [11], roughly a twelfth the number now overhead on Earth [4], with most of its signal pointed at a single site near the south pole [11].
Against that, Heckler's suggestion that the lunar system could eventually beat Earth GPS rests on one specific error term: lunar radio waves do not cross an atmosphere, so they arrive undistorted [12][13]. The advantage is real, though narrow. The reporting carries no accuracy figure for the south pole service and no dates for satellites two through five, so how often a rover will see enough of them at once to fix its position is not something this material answers.
LuGRE is worth being precise about. The NASA and Italian Space Agency experiment acquired GPS signals from the lunar surface in 2025, well outside the coverage those signals were designed for [8]. Acquisition is the hard first step and that was a real result. It also happened on the side of the moon that faces Earth, which is the only side where it can happen: Parker's point is that line of sight is the whole dependency, and the far side never has it [9]. The objection scales badly outward, too. On the source's own figures, Mars sits roughly 583 times farther from Earth than the moon does [3].
The difference is traffic, not difficulty, which is why Apollo is not a precedent here. Twelve astronauts landed between 1969 and 1972 on navigation that looks crude beside GPS [7], and Heckler's account is that those missions never demanded fine spatial precision [c7b]. A permanently staffed site does, because the vehicles have to resolve each other and not just the ground [2][3]. The result is a stack of systems, not one standard. Earth GNSS handles the ranges it reaches, lunar satellites fill in where it does not, and onboard sensors are integrated across both [14].
The sequencing looks deliberate. The first navigation satellite is due about five years before the outpost is meant to be occupied [1], and boots are expected on the surface well before that [16]. Houston's stated ambition is unglamorous by comparison, a live map with moving dots on it [15], but a real-time picture of where everything is turns out to be the same product as the collision-avoidance layer.
