Chief Scientist at NASA sides with Rossi

Dennis Bushnell, Chief Scientist at NASA’s Langley Research Center credits Andrea Rossi with a breakthrough in a new form of energy production.

“I think we are almost over the “we do not understand it” problem. I think we are almost over the “this does not produce anything useful” problem. I think this will go forward fairly rapidly now. If it does, this is capable of, by itself, completely changing geo-economics, geo-politics, and solving climate issues.”

Although he insists that it's not any kind of "cold fusion" process but rather a, as yet unknown, LENR event.
A reaction of the Weak Nuclear Force.
Bushnell believes that heat is generated from beta decay of subatomic particles
This is totally contrary to what Rossi maintains is occurring within the tiny device.
Rossi's comments, “If beta decay explained the reactions in my device, I would have been killed already [by the radiation] and we would have found different isotopes.”

Listen to Bushnell's audio interview - part1 and part2

Further research will uncover the mystery of this tiny contraption.