  Production of $d$, $t$, and $^3$He nuclei in central Pb+Pb interactions was
studied at five collision energies ($\sqrt{s_{NN}}=$ 6.3, 7.6, 8.8, 12.3, and
17.3 GeV) with the NA49 detector at the CERN SPS. Transverse momentum spectra,
rapidity distributions, and particle ratios were measured. Yields are compared
to predictions of statistical models. Phase-space distributions of light nuclei
are discussed and compared to those of protons in the context of a coalescence
approach. The coalescence parameters $B_2$ and $B_3$, as well as coalescence
radii for $d$ and $^3$He were determined as a function of transverse mass at
all energies.
