Clarion spy drone
From Halopedia, the Halo wiki
Clarion Spy Drones are small probes that can propel themselves through space under their own power by either remote or computer guidance. They use a variety of sensors and cameras to scan space and transmit data. They are standard issue on most UNSC vessels. They are also one of the few things that can survive a Slipspace ejection with no damage as they are almost pure Titanium-A.
They are mainly used for reconnaissance but have a variety of uses, including being used as decoys. Admiral Whitcomb used these devices when spying on the Covenant while the Ascendant Justice hid during Operation: FIRST STRIKE.