Segmented Space Telescope Mirror Phasing — 2D

Space telescopes like JWST launch with a primary mirror folded into 18 independent hexagonal segments, each on its own set of actuators. Right after deployment those segments point in slightly different directions, so a distant star shows up as 18 separate smudges instead of one sharp image. This top-down 2D simulator scatters the segments with an adjustable amount of nanometre-scale piston and tip/tilt error — shown directly as per-segment shading and glint offsets — then runs a wavefront-sensing-and-phasing control loop that drives every segment toward a common focus. Watch the focal-plane panel converge to a point, the segment-error bars fall to zero, and the RMS wavefront error / Strehl ratio history trace the approach in real time.