A heat shield protected the one-man Mercury spacecraft against the enormous heat of reentry into the atmosphere beginning at a velocity of more than 27,500 kilometers (17,000 miles) per hour. Like those of other early manned spacecraft, Mercury's heat shield derived from ballistic-missile warhead technology. The dish-shaped shield created a shock wave in the atmosphere that held off most of the heat. The rest dissipated by ablation--charring and evaporation of the shield's surface. Ablative heat shields are not reusable.
This heat shield is a sample from Scott Carpenter's "Aurora 7" spacecraft. An Atlas launch vehicle launched Carpenter on a three-orbit mission called Mercury-Atlas 7 (MA-7) on May 24, 1962, the second U.S. manned orbital flight. The NASA Johnson Space Center gave this sample to the Smithsonian in 1978.
This object is on display in Human Spaceflight at the Steven F. Udvar-Hazy Center in Chantilly, VA.