Pushbroom (linear) vs. whiskbroom (scanning) — why pushbroom is superior.

• No moving mirror → more reliable, longer mission life.
• Longer dwell time per pixel → higher signal-to-noise, stronger signal.
• CCDs are smaller, lighter, lower-power than the optics a scanning mirror needs.
• Disadvantage of pushbroom: calibrating thousands of detectors to produce a uniform radiometric response is difficult (each CCD has slightly different gain/offset) — a given scanner with one detector never has this problem.