Seven Days (TV Series) - The Time Machine

The Time Machine

Descriptions of how the Chronosphere and the time travel mechanisms work were revealed in the early episodes, and in episodes where Russian time travelers or spies attempt to steal Element-115 or the secrets of the Backstep Project (for example, in Season 3, Episode 21 – "Born in the USSR" and in Season 1, Episode 9 – "As Time Goes By").

While it may appear that the time machine is the Chronosphere itself, this is not the case. The Chronosphere has its own power source for navigation and avionics, but it doesn't produce the time displacement field for time travel (explained in Season 1, Episode 9 – "As Time Goes By").

Instead, the Element-115 fuel source, the reactor and the gravitational field generators are located outside the Chronosphere. A waveguide conduit connects the reactor to the Chronosphere, whereby the gravity wave generated by the Element-115 fuel source is "pumped" towards the sphere. The sphere will then latch on to this gravity wave whereby it is converted into a time displacement field, which is a localized region of spacetime distortion (see Season 1, Episode 9 – "As Time Goes By"). Due to the limited amount of Element-115 fuel, it has to be used sparingly. Furthermore, due to the limitations of the reactor size and output power, the time displacement field has sufficient energy to send the Chronosphere back in time for only seven days (see Season 1, Episodes 1 and 2).

It was also mentioned that they can only go back in time seven days due to the limited quantity of the fuel source. The Element-115 fuel source can "regenerate". It will be depleted after each Backstep, and it will take seven days for the fuel to regenerate to an amount necessary to charge the reactor up to 100 percent (see Season 3, Episode 8 – "Tracker").

However, in another episode – Season 3, Episode 21, "Born in the USSR" – the Soviets mentioned that they encountered a mathematical limitation of the time travel mechanism that they were working on, in which it would appear that time travel is limited to only seven days to the past, and nothing more than that. They mentioned that they were unable to overcome this "barrier".

It was implied that Project Backstep still existed many decades into the future. In Season 2, Episode 23 – "The Cure", an NSA agent from the future traveled far back in time to stop a doctor from developing a cancer cure. He revealed that this cure would mutate and cause an epidemic that brought mankind to the edge of extinction. The NSA of the future salvaged more Element-115 from another saucer crash, and used all the Element-115 fuel that they had at one go, thus enabling the Chronosphere to be transported decades into the past.

The Chronosphere gets damaged by most Backsteps (mostly due to the crash-landings). The NSA will send retrieval teams to recover the sphere and deliver it back to NNL. Welders are constantly seen working on the exterior of the sphere in the NNL hangar.

Significantly, the natural laws of time travel within the series operate to prevent cohabitation of a timeline by more than one version of a person or object: anything arriving from the future replaces its past self. Paradoxically, the effects of the future upon the new arrivals remain in place, creating a paradox that allows information to be sent to the past. For this reason, the on-duty chrononaut is typically confined to base as the absence of the chronosphere and/or its pilot is used as a means of determining a Backstep has taken place (and to prevent civilians from seeing Frank vanish into non-existence when replaced by his future self). This concept however is contradicted in a number of episodes, where Backstep personnel appear to become aware of the Backstep only when Frank calls in as 'Conundrum', his backstepping call sign.