Panic button

A panic button is a single-shot emergency beacon employed by all the UNSC armed forces. It has two settings: The 'Red' setting sent out a distress signal, informing allies that the team's mission has failed and they need immediate assistance. The 'Green' signal merely activates a homing beacon to inform UNSC forces of the location of a hidden objective.

In 2525, the Spartans used a panic button to mark a homing beacon on Eridanus Secundus. Despite this, the asteroid base survived until 2552. However, since the UNSC was quite soon after in the middle of a war, they probably didn't have time to deal with a bunch of pirates.

In 2552, Kamal Zaman hacked his chatter to use as a panic button should things go wrong while meeting with gangster Aiden Maki.