Indian born American citizen, Noshir S. Gowadia, was recently sentenced to 32 years in prison, after being convicted of spying for China. Gowadia sold China details of the B-2 bombers engine exhaust system. This technology makes it more difficult for heat sensors (like heat seeking missiles) to detect the exhaust of the B-2 engines. The information Gowadia provided would enable the Chinese to tweak their heat seeking missiles to have a better chance of hitting a B-2. Gowadia also helped Chinese engineers apply this technology to the design of a stealthy cruise missile. This technology would also be essential for the new Chinese J-20 aircraft.
Gowadia ran a Hawaii based spy ring since 1999, and made six clandestine trips to China. Gowadia worked on the B-2 project from 1968 to 1986, as one of the designers. Gowadia was arrested six ago. He could have gotten life in prison, and anything less than that might indicate he had something to trade (on Chinese intel efforts).