Hal Moseley

From Memory Alpha, the free Star Trek reference.

Hal Moseley was a scientist on Penthara IV.

He enlisted the help of the USS Enterprise-D when the planet was threatened by enviromental changes caused by an asteroid that hit an uninhabitant part of the planet. A nuclear winter was a possiblity. La Forge and Data tried to help with the problem. At first the Enterprise used phasers to release gas into the atmosphere to counter the effects of the nuclear winter. However, this only caused more damage as the planet was hit with a series of quakes.

Moseley and La Forge would decide on a solution that would either solve the problem or kill everyone on it. They initiated a chain reaction in the atmosphere that solved the problem. (TNG: "A Matter of Time")

Hal Moseley was played by Stefan Gierasch.