Now a generic term for artificial turf, a vile invention designed to replace grass sports fields. AstroTurf was a brand name for an early artificial surface, first used in the Houston Astrodome (the first indoor football/baseball stadium) when the newly-painted roof made it difficult to maintain its grass surface. The original clear (or slightly translucent?) roof made it hard to see fly balls in the daytime. Sunlight is a two-edged sword.