This article is about the UNSC equipment. If you were looking for the publication, see STARS Magazine.
STARS are baseball-sized satellites that remain in orbit above combat situations to provide in-field unmanned tactical command and to relay mission results and statistics to the Office of Naval Intelligence post-mission. They are capable of mapping large areas and providing real time topographical intelligence. It is likely that STARS are used exclusively by the Office of Naval Intelligence because of their advanced nature and specific function.
STARS are extremely useful; they covertly relay communications, topography information, enemy locations, and allied locations and equipment positions to the HUD of allied units in range. Furthermore, channels like TEAMBIO are relayed across STARS. They also broadcast orders for individual units. STARS help the UNSC military coordinate even complex operations easily and under stealth conditions, where even COM chatter can give away unit positions.
However, as per Mendez, "Machines break", and STARS was accredited for the over 99% fatality rate of Beta Company in the Battle of Pegasi Delta, where STARS failed to recognize the looming presence of no less than seven Covenant Cruisers over the Covenant tritium factory there. This led to a massive Seraph plasma charge bombardment and pulse laser sterilization of the SPARTAN-IIIs.
It is unknown why there was such a critical failure of the STARS. One hypothesis is that the STARS mistook the seven cruisers as part of the factory. More likely, however, it was simply decided to send the Spartans-IIIs in anyway.