The Marine Space Corps, abbreviated MSC, sent an expedition to Exxilon in search of the rare mineral parrinium, which was found in vast quantities on that planet and needed desperately to cure a galactic plague. (TV: Death to the Daleks) The Time Lords of the Time War believed this event took place in the 27th century, (PROSE: Dalek Combat Training Manual) whilst post-Time War human historians recalled that it came "hundreds of years" following the 26th century Dalek War and itself was soon followed by a Dalek invasion of the galaxy. (PROSE: Dalek: The Astounding Untold History of the Greatest Enemies of the Universe)
When a second wave of the space plague struck, the Marine Space Corps was sent to guard the mining operation. As the fleet prepared to leave with its bounty of parrinium, the Dalek Empire activated a new power-draining beacon, delaying the launch. Having prepared for this possibility, the Marine Space Corps detonated simple explosives that destroyed the beacon and restored power to the planet. (AUDIO: The Dalek Protocol)
The MSC was active when the starliner Alaska crashed on the Dalek Asylum planet, which led to the planet's destruction a year later. Following the crash, Space Traffic Control had strongly advised against an MSC rescue mission in their report. (PROSE: The Secret Lives of Monsters)