From Halopedia, the Halo wiki
A Malakost tracker is a device designed to be planted on an enemy craft so that it can be tracked. Malakost trackers tenaciously cling to the exterior hulls of vehicles. They can withstand much duress and even remain attached and functional after atmospheric reentry.
On September 1, 2558, in the midst of a battle over Carrow, the Sangheili fleetmaster, Rojka 'Kasaan, tossed a malakost tracker onto the hull of the Class-5 Bumblebee escape pod, Whiskey Tango Foxtrot One. The three Spartan-IIs of Gray Team were in the process of escaping from his ORS-class heavy cruiser, Unwavering Discipline. The signal Rojka received from the tracker told him that the humans looked to be steering for the city of Suraka as they descended. The tracker failed when the pod violently crashed into the ground.
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