Distress call A distress call was any signal that requested assistance . It was typically sent by an individual or group that encountered a problem they could not handle on their own . The purpose of the signal was to summon those who could help . A widely known distress signal was " SOS " , which dates back to the early 20th century , when broadcast signaling was still a new science . An international convention met to debate and select a " universal " distress call , and " SOS " was selected by most . It did not truly become universal until after the year 1912 , when the , an ancient Earth water - going vessel , sank after striking an iceberg . Her radio operators were forced to send several types of distress signal to ensure the meaning would not be lost . In 2152 , answered a distress call of an alien vessel according to the captain ' s starlog . ( ) In the 23rd and 24th century , starship s , starbase s , and colonies could emit distress signals which were carried in space or through subspace to anything which could receive it . This could include other ships , bases , and colonies . In 2254 , the detected an old - style distress signal , a radio wave . ( ) In 2266 , the " Enterprise " detected an Earth - style SOS while hundreds of light year s from Earth . The source was revealed to be a ground station on Earth Two , an exact copy of Earth . ( ) Because of tense intergalactic relations , distress signals between races may or may not have received a response . In several cases , a Federation ship crossed into , for example , the Neutral Zone , to answer a distress signal . However , extreme care was taken in these situations , as some enemies would sometimes emit false distress signals to lure starships in and attack them . ( ) When passing near Mab - Bu VI in 2368 , the received a faint distress signal that Data was later able to identify as a Starfleet subspace distress signal standard to starships . The signal was sent by the crew of the , which was lost in the sector over two hundred years earlier . ( ) The Federation planetary distress signal was an emergency transmission that was to be used only when a Federation world was under imminent threat . Prior to transmission of a planetary distress signal , the head of council for the Federation planet needed to declare a planet - wide state of emergency . The planetary distress signal was first known to have been transmitted in 2286 , when a massive alien probe of unknown origin arrived in the Sol system , and began transmitting a signal that had a disruptive effect on power systems , and began ionizing the planet ' s atmosphere . All Earth orbiting space stations and starships were quickly rendered powerless , along with the planet ' s power generating systems . Within two hours , the president of the Federation Council declared a state of emergency . Massive weather systems caused by the drop in air pressure caused widespread damage across the planet . Six hours into the crisis , the Federation president transmitted a planetary distress signal . The following is a transcript of the message : The crisis was relieved by a group of Starfleet officers who were returning from . One of the officers analyzed the transmissions of the probe and determined the transmissions were directed to an extinct species of humpback whale s . The officers managed to retrieve a pair of the whales and delivered them to Earth . The probe shut down its transmissions and left the system . ( ) Another example of a planetary distress call is that which was transmitted by the Scalosian s to attract starship s to their planet so they could use the crew of the ship to repopulate their planet . The following is a transcript of part of the message : In 2368 the received a priority one distress call from the Federation colony on Dulisian IV , which requested an evacuation because of a massive failure of the environmental support systems . The crew later learned that this distress call was a faked one from the Romulan s to move the " Enterprise " - D away from the Vulcan ships . ( ) In 2369 the " Enterprise " - D received another distress call via their long range sensor s from a Romulan warbird . Worf informed Commander Riker about this call while he was treated in sickbay . ( ) The same year Major Kira Nerys and Doctor Julian Bashir received a priority one broad band distress signal from Ty Kajada aboard the Kobliad transport ship " Reyab " . ( ) In 2371 , Gathorel Labin transmitted a distress call , which was picked up by the . Upon arrival , it was found that Labin only transmitted the distress call because he sensed the crew of " Voyager " was in distress . ( ) In 2372 , Captain Kasidy Yates sent a priority one distress call to Deep Space 9 when the " Xhosa " was attacked by a Klingon Bird - of - Prey . The message was interrupted and Captain Sisko manned the to rescue the " Xhosa " . ( )