Precision measurements of muon capture on the proton and deuteron with MuCap

The MuCap collaboration recently released a first result of a measurement of the singlet capture rate $\Lambda_s$ for the muon capture process $\mu+p \rightarrow n+v$, unambiguously determining the pseudoscalar form factor $g_P$ of the charged electroweak current of the proton; The final results of this analysis on $g_P$ and the experimental situation will be presented. As a follow up experiment the collaboration is planning a measurement of the muon capture rate on the deuteron to 1\% precision. This would provide the most accurate experimental information on the axial current interacting with the two nucleon system and determine the low energy constant $L_{1A}$ relevant for solar neutrino reactions and the SNO experiment.