Heat-shielding tiles on the space shuttle were made from ceramics, for example.

Now researchers have used a 3D printer to make customized ceramic parts that have also overcome the Achilles' heel of ceramic objects: their tendency to crack.

The finding could open the door to a new class of ceramic-body or ceramic-engine jets, perhaps even a hypersonic craft that can fly from New York to Tokyo in a few hours.

"If you go very fast, about 10 times speed of sound within the atmosphere, then any vehicle will heat up tremendously because of air friction," said Tobias Schaedler, senior scientist at HRL Laboratories in Malibu, Calif. "People want to build hypersonic vehicles and you need ceramics for the whole shell of the vehicle."

Schaedler and colleagues at HRL invented a resin formulation that can be 3-D printed into parts of virtually any shape and size.