Stippled Navy Star Field — 2 museum-grade prints in this palette. ICESat-2 closed a decade-long gap after the original ICESat GLAS instrument ceased operations, maintaining the laser altimetry record that IPCC assessments and ice-sheet modellers depend on. The mission's six-beam pattern lets scientists distinguish slope from roughness on polar ice — a subtle engineering choice with major science payoff. MESSENGER closed a half-century gap between Mariner 10's three Mercury flybys (1974–75) and sustained orbital science. Confirmation of water ice in permanently shadowed polar craters — despite Mercury's proximity to the Sun — reshaped models of volatile delivery across the inner solar system.