Over the course of the series, Black Mesa is revealed to be conducting top-secret research into various fields, such as teleportation and experimental weapons research.

I was the top pilot in the United States Air Force's most top-secret research center.

Robert Roy Pool, a contributing screenwriter, stated that his script, in which an anti-gravity device is used to deflect a comet from a collision course with Earth, was "much more in line with top-secret research."

There was a connection between Randolph and top-secret research conducted on the base, but the link might not be my mother or her retrovirus.

The men were carrying out top-secret research into radar, and until now the incident has been shrouded in mystery.

For 15 years, Prof. Uzi Even had done top-secret research for the military.

Max earned a doctorate in physics and got a job doing top-secret research.

Federal officials usually say that such top-secret research is pursued mainly to understand how the Russians might use these weapons and that they do not plan to use nuclear-driven beams.

From this crucible, Oppenheimer emerged with the leadership capabilities that would eventually place him in charge of top-secret research into the creation of nuclear weapons.

Chelyabinsk Oblast has had a long association (since the 1940s) with top-secret nuclear research.