History of Siphon

'''Siphon''' is an Acceleron encounter from The Edge of Fate. It is one of two Accelerons, alongside Surveillance, that the second step of The Gorge Strangelet quest requires. Per Destinypedia, the Vex sealed the way forward using energy drawn from an Acceleron, and obtaining Siphon and Surveillance lowers the Vex blockades. This unlocks the missions Calculus and Disruption, which must both be completed to advance the quest.