Heat shield materials are the size of hockey pucks when tested in the arc jet and submitted to temperatures two or three times that of the sun.

The material pictured here inside the arc jet is being subjected to energy of 1,000 watts per square centimeter.

Inside the arc jet facility.

Frank Hui, pictured left, an aerospace test engineer, and Ernest Fretter, who oversees the arc jet facility at NASA Ames, where scientists are testing materials that will eventually insulate spacecraft traveling to the moon.

Temperature gauges inside the arc jet facility allow scientists to simulate conditions and temperatures that a spacecraft would encounter on re-entry to the Earth's atmosphere.

Outside the arc jet facility, instruments measure the surface temperature of the heat shield materials to see how they react to extreme temperatures.