Earth vessel (31st century)

Time travel pods were craft used by historians from the distant future, from as early as the 26th century, to as late as the 31st century, to study various points in time. (TNG: "A Matter of Time"; ENT: Future Tense)

Pods commissioned during the 31st century were powered by a temporal displacement drive. The also could absorb EM radiation, allowing them to remain undetected by the sensor technology of earlier centuries. Their futuristic technology even allowed their interiors to have considerably greater dimensions than the exterior. One such pod traveled back to the 22nd century where it apparently suffered some sort of critical disaster. (ENT: Future Tense)

The pod was heavily damaged and its sole occupant long dead by the time it was discovered by Enterprise in 2152. The damaged pod was emitting temporal radiation, which affected individuals too close to the pod, making close study a risk. Unfortunately, both the Suliban Cabal and Tholian Assembly also learned of the pod's existence and sent vessels to retrieve it. Their plans where thwarted when Enterprise's crew used a temporal beacon assembled using technology left behind by a temporal agent known only as Daniels to send a signal to the future. Within seconds of the beacon being activated, the pod, the dead pilot, and the beacon itself all vanished, possibly having been retrieved by operatives from the future. The fate of the pod and nature of the disaster that killed its pilot remain a mystery. (ENT: Future Tense)