  Type-I X-ray burst (XRB) light curves are sensitive to the model's nuclear
input and consequently affects the model-observation comparisons.
$^{22}$Mg($\alpha$,p)$^{25}$Al is among the most important reactions which
directly impact the XRB light curve. We report the first direct measurement of
$^{22}$Mg($\alpha$,p)$^{25}$Al using the Active Target Time Projection Chamber.
XRB light curve model-observation comparison for the source $\tt{GS 1826-24}$
using new reaction rate implies a less-compact neutron star than previously
inferred. Additionally, our result removes an important uncertainty in XRB
model calculations that previously hindered extraction of the neutron star
compactness.
