  Gamma-ray spectrometers with high spectral resolution have been operated in
space since 2002. Major efforts to understand instrumental response and
backgrounds are a requird before detailed science interpretations can be
derived; by now, high-resolution line-shape studies have resulted in
significant astrophysical constraints, not only through studies of solar-flare
details, but also for nuclear processes in the Galaxy: 44Ti from the Cas A
supernova could only be detected in the low-energy lines at 68 and 78 keV, the
1157 keV line from the same decay is not seen; this constrains 44Ti ejection in
core collapse supernovae. Diffuse nucleosynthesis is studied through 26Al,
60Fe, and positron annihilation gamma-ray measurements. The gamma-ray line from
decay of radioactive 26Al could be measured at unpredecented spectroscopic
precision. The new determination of the total mass of 26Al produced by stellar
sources throughout the Galaxy yields 2.8 +/-0.9 M_solar, and the interstellar
medium around 26Al sources appears characterized by velocities in the ~100 km
s-1 region. 60Fe is clearly detected with SPI, its intensity ratio to 26Al of
\~15% is on the lower side of predictions from massive-star and supernova
nucleosynthesis models. Nucleosynthesis sources are probably minor contributors
to Galactic positrons; this may be deduced from the bulge-centered spatial
distribution of the annihilation gamma-ray emission, considering that
nucleosynthesis sources are expected to populate mainly the disk part of the
Galaxy. It is evident that new views at nuclear and astrophysical processes in
and around cosmic sources are being provided through these space missions.
