Alternate reality
A Magellan probe
A Magellan probe was a type of space probe used in the alternate reality.
During the mid-23rd century, the Federation used these probes to chart a way through the Necro Cloud. Krall managed to obtain a Magellan probe, and linked it to his own computers, thus managing to piggyback onto its subspace links to gain access to the Yorktown database.
USS Enterprise officers Nyota Uhura and Hikaru Sulu attempted to use the probe to send distress signal to Yorktown. However, Uhura and Sulu were caught and Krall had their coordinates altered to strand the rescue ships in the nebula. (Star Trek Beyond)