Among the current population of the 81 known trans-Neptunian binaries ( TNBs ) , only two are in orbits that cross the orbit of Neptune .
These are ( 42355 ) Typhon-Echidna and ( 65489 ) Ceto-Phorcys .
In the present work , we focused our analyses on the temporal evolution of the Typhon-Echidna binary system through the outer and inner planetary systems .
Using numerical integrations of the N-body gravitational problem , we explored the orbital evolutions of 500 clones of Typhon , recording the close encounters of those clones with planets .
We then analysed the effects of those encounters on the binary system .
It was found that only \approx 22 \% of the encounters with the giant planets were strong enough to disrupt the binary .
This binary system has an \approx 3.6 \% probability of reaching the terrestrial planetary region over a time scale of approximately 5.4 Myr .
Close encounters of Typhon-Echidna with Earth and Venus were also registered , but the probabilities of such events occurring are low ( \approx 0.4 \% ) .
The orbital evolution of the system in the past was also investigated .
It was found that in the last 100 Myr , Typhon might have spent most of its time as a TNB crossing the orbit of Neptune .
Therefore , our study of the Typhon-Echidna orbital evolution illustrates the possibility of large cometary bodies ( radii of 76 km for Typhon and 42 km for Echidna ) coming from a remote region of the outer Solar System and that might enter the terrestrial planetary region preserving its binarity throughout the journey .