Three forces sent expeditions into the Hadron Expanse while the warp routes remained viable, in order to reconoitre as much as possible, exploit any resources and return to the Aleph Sector. For the Imperium, the Crusade and Loyalist forces managed to ignore their differences over Libria long enough to build a formidable task force. Lead by Inquisitor Huron, who had remained neutral in the argument between Vorushko and Hathek, the imperium gathered together a large fleet of warships, including elements of Admiral Pendragon's and Admiral Enkvist's fleets, and with the reappearance of Admiral Hector to Aleph sector operations.

Added to this were several regiments of Novgorod Guard, who continued to flood in to the sector via Brimlock in an impressive display of seemingly inexhaustible manpower. Backing this up, the Adeptus Mechanicus, crucially interested in finding STC components and space hulks in the Hadron Expanse, added their own forces to the expedition.

The alliance, short on manpower and extended on all fronts, supplied a much smaller force. Only one federal battlegroup took part and this was undersized, and the only ground forces sent were a few hunter cadres from Skyfall's Aleph Expansion sphere. For chaos, despite being entrenched in wars or internecine conflicts, the ruinous powers managed to assemble a warfleet under Admiral Thok, and several thousand Iron Warriors. In addition, always looking for profit, the Dark Eldar kabal of the shattered silence also sent its own force from Commoragh.

The exploration of the Hadron expanse continued for around a terran month, with the Imperial forces out of Brimlock dominating much of the available systems. Skirmishes on the ground were largely few and far between, but there were two major engagements of note. In one, the Mechanicum met the bulk of Skyfall's entire force, and a large full scale battle took place. After hours of hard fighting it was the tau who were narrowly defeated, and this early set back seriously impacted the alliance's cause, despite the federal fleet defeating admiral Pendragon. Following that engagement it became clear the imperium outnumbered alliance forces but at least 3-1, and the alliance moved their operations further to the galactic south, effectively yielding much of the expanse to the imperium.

At the same time, the middle of the expanse was being contested by the forces of chaos and the imperium, with Stahl gaining victory over the Novgorod Guard in one system, but losing to the Mechanicum in another. The too and fro of engagements culminated in a large set piece space battle, which put much of the imperial fleet under Hector and Enkvist against mad admiral Thok and his pirate dark eldar allies.

The space battle itself was decisive, with the dark eldar seen off and Thok's fleet badly damaged. Although Thok once again escaped in his crippled "planet killer", the victory gave the imperium domination over the northern expanse, and despite being defeated on the ground by Skyfall's cadres and the dark eldar of the shattered silence, it was the control of the space lanes which decided the Hadron expedition. By 1803.016M42 the warp storms were closing in once more, and all sides prepared to leave the area. The mechanicum had retrieved several key artefacts and space hulks, while the forces of chaos had seen little gain for their efforts. The alliance had profited from their small expedition but knew there was nothing in the southern Hadron Expanse which would aid them in their many wars, and the imperial success bolstered the imperial will to resist on several fronts.