A planet bearing a dormant time portal that sent Brad Boimler and later Beckett Mariner from 2381 back to Pike's Enterprise in the crossover episode Those Old Scientists.
Krulmuth-B is the planet at the centre of the Strange New Worlds episode Those Old Scientists, the crossover with Lower Decks. In 2381 the USS Cerritos is carrying out a routine check of a ring-shaped portal there. It activates while Boimler poses for a picture and drops him more than a century into the past, where the Enterprise is studying the same object.
Orions seize the portal before he can be sent back. Boimler recalls that history credits an Orion science vessel with finding it, and Pike gives them the discovery in return for the device. Mariner then comes through after him, using up the last of its power source.
The portal runs on horonium, an alloy no longer made. Boimler and Mariner realise the Enterprise carries a piece of the NX-01 containing the metal, enough for one trip home.