Bosonite

"But, if you want to make a special star, say, to power our protostar drive to get us back to Voyager, you need a special kind of matter, the perfect matter, bosonite, with all the exotic properties we need."

– Rok-Tahk, 2384 ("A Tribble Called Quest")

Bosonite is an element vital to the creation of an artificial protostar.

In 2384, the USS Protostar visited an Class M planet on the edge of either the Beta Quadrant or the Delta Quadrant with a natural supply of the bosonite that the crew needed to build a new proto-core for the ship. However, most of the planet's natural resources had been consumed by the omega tribbles, leaving only trace amounts of bosonite in the soil. The single surviving large deposit was in the middle of the tribble nest, causing the Protostar crew to work together with Doctor K'ruvang to create a retrovirus to stop the tribbles. The crew succeeded in beaming the necessary bosonite into the inactive proto-core, but became cornered by the tribbles. Preferring to die with honor, K'ruvang attempted to detonate a vein of bosonite despite the fact that the chain reaction could destroy the entire region, forcing the crew to restrain him.

Later, Jankom Pog successfully used the bosonite to create a new proto-core for the ship, restoring power to the protostar drive. (PRO: "A Tribble Called Quest")