The science station orbiting Tanuga IV where Doctor Nel Apgar worked on a Krieger wave converter, destroyed in 2366 in an explosion for which William Riker is accused of murder.
The Tanuga IV research station is the scene of the crime in the Next Generation episode A Matter of Perspective. Doctor Nel Apgar lives there with his wife Manua and his assistant Tayna while developing a converter for Krieger waves, a new energy source that Starfleet is funding.
Riker visits to check on progress. As he beams back to the Enterprise the station explodes, killing Apgar, and the Tanugan investigator Krag demands his extradition. Picard has the conflicting accounts of Riker, Manua and Tayna replayed on the holodeck.
The recreation, together with bursts of radiation striking the Enterprise, shows that the converter already worked. Apgar had fired it at Riker during transport, hoping to disguise a murder as an accident, but the beam reflected and destroyed the station's reactor instead.