Since most heat shields are not good insulators, they will conduct heat through them.

This means that there is no need for bulky life support systems and heat shields.

Stocks were somewhat angular and heat shields were made of wood.

He slowed, bringing the wings out to minimal sweep, rolling back the heat shields, for a look around.

The heat shields were still intact and the computer assured him that they would not crack or fall off on the journey through the atmosphere.

Their heat shields fused into a single, almost solid mass as they struggled.

"Why do spacecraft need heat shields coming back to Earth but not leaving?"

In order to not burn up, spaceships need therefore been very expensive and sometimes failing heat shields.

What kind of heat shields do you use?

They also contain heat shields made of polymers or heat-resistant wax.