  Nuclear reaction rates are a fundamental yet uncertain ingredient in stellar
evolution models. The astrophysical S-factor pertaining to the initial reaction
in the proton-proton chain is uncertain at the 1% level, which contributes a
systematic but generally unpropagated error of similar order in the theoretical
ages of stars. In this work, we study the prospect of improving the measurement
of this and other reaction rates in the pp chain and CNO cycle using
helioseismology and solar neutrinos. We show that when other aspects of the
solar model are improved, then it shall be possible using current solar data to
improve the precision of this measurement by nearly an order of magnitude, and
hence the corresponding uncertainty on the ages of low-mass stars by a similar
amount.
