Schematic diagram of the New Horizons trajectory (orange) compared with the Voyager (green) and Pioneer (red) trajectories, all projected into the ecliptic plane (Voyager 1 and 2 are ∼30° above and below this plane, respectively). The colored background indicates the fraction of the upstream interstellar H that survives at various locations from the “hot model” (Thomas 1978; Wu & Judge 1979), as was done to show the interstellar hydrogen shadow (dark region downwind of the Sun) by McComas et al. (2004).