  Significant advances have been achieved through the latest improvements in
the photometric observations accomplished by the recent space missions,
substantially boosting the study of pulsating stars via asteroseismology. The
TESS mission has already proven to be of relevance for pulsating white dwarf
and pre-white dwarf stars. We report a detailed asteroseismic analysis of the
pulsating PG 1159 star NGC 246 (TIC3905338), the central star of the planetary
nebula NGC 246, based on high-precision photometric data gathered by the TESS
space mission. We reduced TESS observations of NGC 246 and performed a detailed
asteroseismic analysis using fully evolutionary PG 1159 models computed
accounting for the complete prior evolution of their progenitors. We
constrained the mass of this star by comparing the measured mean period spacing
with the average of the computed period spacings of the models and also
employed the observed individual periods to search for a seismic stellar model.
We extracted 17 periodicities from the TESS light curves from the two sectors
where NGC246 was observed. All the oscillation frequencies are associated with
g-mode pulsations, with periods spanning from ~1460 to ~1823s. We found a
constant period spacing of $\Delta\Pi= 12.9$s, allowing us to deduce that the
stellar mass is larger than ~0.87 Mo if the period spacing is assumed to be
associated with l= 1 modes, and ~ 0.568 Mo if it is associated with l= 2 modes.
The less massive models are more consistent with the distance constraint from
Gaia parallax. Although we were not able to find a unique asteroseismic model
for this star, the period-to-period fit analyses suggest a high-stellar mass
($\gtrsim$0.74 Mo) when the observed periods are associated with modes with l=
1 only, and both a high ($\gtrsim$ 0.74 Mo) and intermediate (~0.57 Mo) stellar
mass when the observed periods are associated with modes with l= 1 and 2.
