  (Abreviated) Comet C/2017 K2 PANSTARRS drew attention to its activity already
at a time of its discovery in May 2017 when it was about 16 au from the Sun.
This Oort spike comet will approach its perihelion in December 2022, and the
question about its dynamical past is one of the important issues to explore. To
this aim it is necessary to obtain its precise osculating orbit, its original
orbit, and propagate its motion backwards in time to the previous perihelion.
We study a dynamical evolution of C/2017 K2 to the previous perihelion
(backward calculations for about 3-4 Myr) as well as to the future (forward
calculations for about 0.033 Myr). Outside the planetary system both Galactic
and stellar perturbations were taken into account. We derived that C/2017 K2 is
a dynamically old Oort spike comet (1/a$_{prev}$ = (48.7 $\pm$ 7,9) x10$^{-6}$
au$^{-1}$) with the previous perihelion distance below 10 au for 97 per cent of
VCs (nominal q$_{prev}$ = 3.77 au). It means that C/2017 K2 has already visited
our planetary zone during its previous perihelion passage. Thus, it is almost
certainly a dynamically old Oort spike comet.
