Model answer

IKONOS was the first U.S. commercial sub-meter satellite — launched 1999, retired 2015. Sub-meter means you can pick out individual cars and rooftops from space.

Big deal because before IKONOS, that resolution was military-only.

It carries a high-detail black-and-white panchromatic band plus four lower-detail color bands, which you fuse together (“pan-sharpening”) to get color at the pan resolution.

It paved the way for today’s commercial high-res constellation — WorldView, GeoEye, Pléiades, SkySat.

🔬 Show the science / technical version

• First commercial sub-meter satellite (Space Imaging, Sept 1999 – Mar 2015).
• Altitude ~681 km, sun-synchronous.
• Bands: Pan 0.45–0.90 µm at 1 m; 4 MS bands (B/G/R/NIR) at 4 m.
• Radiometric 11-bit → 2 048 levels.
• Off-nadir up to ±45°, swath ~11–13 km, revisit 1–3 days.