Operation Time Fracture was the operation by UNIT to send a human team through the Time Fracture using the Portal Stabilisation Gateway and, if possible, discover whatever was causing it on the other side.
UNIT initially wanted to send some of their own top operatives on the mission, but at the last minute, the Doctor vetoed this part of the plan and substituted their own list of trustworthy people, all of them civilians with no prior association with UNIT. Kate Stewart reluctantly acquiesced to the Doctor's request and wrote to the people on the list to explain the Fracture and the mission to them. (PROSE: Welcome to Operation Time Fracture) Kate Stewart sent out a message to recruit those people, breaking UNIT protocol, (WC: 14684 UNIT Field Log) and a group of four humans received the message and fought off the Daleks, Cybermen, and Weeping Angels in UNIT HQ, before travelling to an alien market, (PROSE: And now for a story...) similarly to a woman who received the message. She would travel to 2156 and encounter Brolls, 1590, 2206 and 2007. (WC: Full-Length Trailer: Time Fracture) Another recruit was Tia Kofi, who had been contacted by the Eleventh Doctor. Doctor Errol Courtney, in charge of briefing the newcomers, found it frustrating that most of them had no knowledge of things like astrophysics and quantum mechanics. (WC: Tia Kofi Enters the Time Fracture!)
UNIT also issued Field Logs to the participants, warning them from engaging Zoria (PROSE: Zoria) and the Cybermen who had began to appear as a result of the Time Fracture. (PROSE: Cybermen) UNIT also said in a Field Log about Lord Cardinal Romanadvoratrelundar that, if they survived Gallifrey's destruction, would be a useful ally in completing Operation Time Fracture. (PROSE: Lord Romanadvoratrelundar) On another occasion, UNIT told their "civilian volunteers" to remain vigilant when the Silence infiltrated UNIT HQ. (WC: There’s been a breach...)
Robert Dudley would sign off his transmissions to the UNIT Black Site with an Operation Time Fracture insignia. (WC: This is Sergeant Robert Dudley., Dudley here., Is anyone receiving these transmissions?)