Lazar's Element 115 claim
Lazar claims the disc propulsion relies on a stable isotope of Element 115, which had not been synthesized in 1989, generating a gravitational field that warps space ahead of the craft. Element 115 (Moscovium) was first synthesized in 2003 in Dubna, Russia, with an extremely short half-life of well under one second; a stable isotope has not been demonstrated.
Background
Lazar claims the disc propulsion is based on a stable isotope of the - then un-synthesized - Element 115 (today officially 'Moscovium'). It is said to generate a gravitational field that warps space in front of the craft. In 1989 this was considered physically absurd - Element 115 had not yet been synthesized. In 2003 synthesis was achieved (Dubna, Russia), though with an extremely short half-life in the millisecond range. A stable isotope as Lazar claims has to this day not been demonstrated.