  We present initial results from JWST NIRSpec integral field unit observations
of the nearby Supernova (SN) 1987A. The observations provide the first
spatially-resolved spectroscopy of the ejecta and equatorial ring (ER) over the
1-5 \mu m range. We construct 3D emissivity maps of the [Fe I] 1.443 \mu m line
from the inner ejecta and the He I 1.083 \mu m line from the reverse shock
(RS), where the former probes the explosion geometry and the latter traces the
structure of the circumstellar medium. We also present a model for the
integrated spectrum of the ejecta. The [Fe I] 3D map reveals a
highly-asymmetric morphology resembling a broken dipole, dominated by two large
clumps with velocities of ~2300 km/s. We also find evidence that the Fe-rich
inner ejecta have started to interact with the RS. The RS surface traced by the
He I line extends from just inside the ER to higher latitudes on both sides of
the ER with a half-opening angle ~45 degrees, forming a bubble-like structure.
The spectral model for the ejecta allows us to identify the many emission
lines, including numerous H_2 lines. We find that the H_2 is most likely
excited by far-UV emission, while the metal lines ratios are consistent with a
combination of collisional excitation and recombination in the low-temperature
ejecta. We also find several high-ionization coronal lines from the ER,
requiring a temperature > 2 \times 10^6 K.
