From The Stargate Omnipedia
Goa'uld Buster missile
Twin weapons conceived by the Pentagon and Major Samuels
as a preemptive strike against two Goa'uld Ha'tak
motherships which settled into Earth orbit shortly following the reactivation of the S.G.C.
Each weapon was a naquadah
-enhanced Mark 12-A warhead yielding a potential excess of one thousand megatons. Impacting against Goa'uld Ha'tak shielding, the weapons proved to be entirely ineffective.
The Serpent's Lair - Arrogant in his plan of success, Samuels is crushed when he realizes the Goa'uld Busters have no hope of saving Earth.