Of carbon, really.

Km/H (15 045 MPH) EXIT BLACKOUT 12 MIN TO TOUCHDOWN 1079 m (2540 FT) TO RUNWAY 496 km/H (308 MPH) 41-m (135-FT) ALTITUDE FLARE TO 1.5 WHEELS DOWN 14 SEC TO TOUCHDOWN 282 km (175 MILES) 26 876 km/H (16 700 MPH) MAXIMUM HEATING 20 MIN TO TOUCHDOWN 335 m (1100 FT) TO RUNWAY 496 km/H (308 MPH) 41-m (135-FT) ALTITUDE FLARE TO 1.5 WHEELS DOWN 14.