America tests 'the most dangerous nuclear bomb ever produced': F-15 drops $1trillion super-nuke that has an adjustable yield and is more accurate than ever

The US National Nuclear Security Administration (NNSA) has revealed that it has conducted a second series of test flights involving an upgraded version of a nuclear bomb that has been part of the U.S. arsenal for decades.

An F-15E from Nellis Air Force Base dropped an inert version of the weapon over the Nevada desert earlier this month as well as in March to test its non-nuclear functions as well as the plane's ability to carry the bomb.

Work on the B61-12 has been ongoing for years, and government officials say latest tests using mock versions of the bomb will be vital to the refurbishing effort.

The bomb is described as the most dangerous nuclear device ever produced because its yeild can be adjusted between the equivalent of 50,000 tons and 300 tons of TNT. It is also more accurate than ever.

With a mere puff of dust, the mock bomb landed in a dry lake bed at the Tonopah Test Range.

Scroll down for video