Bulwark defensive satellite

The Bulwark defensive satellite, referred to as the XMA/1 Deployable Defensive Satellite by the UNSC, was a piece of technology developed jointly by the Alliance of Sangheili Clans and United Nations Space Command, as a short term, rapidly deployable answer to the problem of UNSC ships' vulnerability to Covenant energy weapon fire. The Bulwark satellite was roughly fifteen metres in diameter and was deployed by Sangheili Defence Force and UNSC Navy warships, where it would remain stationary and project a round, one-way shield 'disc' three hundred and fifty metres across. This shield would allow a UNSC warship to fire on Covenant vessels while itself remaining protected from Covenant return fire. While intended as an ultra short-term solution (it was expected that UNSC vessels could be retrofitted with Sangheili shields by the end of 2553) to address the chronic weakness of UNSC vessels; Bulkwark satellites continued to be used even after shipboard shields within the UNSC Navy were widespread. Later, smaller versions of the Bulwark were produced as deployable countermeasures for large ships. The Bulwark saw its first operational usage during Operation: REAR GUARD, just weeks after it was put into production. The satellite recieved different designations by the factions who utilised it; being the Bulwark defensive satellite in Sangheili use and the XMA/1 Deployable Defensive Satellite in UNSC service. The satellite saw usage throughout the Remnant War and later, but had been replaced by dedicated countermeasure systems by the beginning of the Swarm War.

The UNSC had already been experimenting with protective deployable shields by 2552, the most successful development being the employed by the  of  These devices, however, were extremely fragile as well as being prohibitively heavy, whilst also having a limited usage period due to power constraints. With the assistance of Sangheili technology, the Bulwark was far more advanced than its somewhat primitive predecessors; being able to directly protect UNSC warships from limited numbers of plasma torpedo and energy projector attacks; whilst maintaining long operating time, a 'one-way' effect and enhanced deployability.