In the pioneering study of asteroid mineralogy using ground-based
remote sensing, McCord et al., [1970] determined
that the second largest main belt asteroid, 4 Vesta,
is the mineralogical equivalent of basaltic achondrite meteorites.
Since this discovery, dynamic modelers have pondered and predicted
mechanisms which would deliver material from the middle of the main
asteroid belt to Earth [e.g. Wisdom, 1985]. In a
report by Binzel and Xu [1993], the discovery of 20
objects with reflectance spectra indicating the predominant
presence of low-calcium pyroxene that is characteristic of basaltic
achondrite meteorites provides observational evidence supporting
the genetic relationship between Vesta and basaltic achondrite
meteorites. They used a Charge-Coupled Device (CCD) spectrometer
and observed many small, main belt asteroids with orbital elements
similar to Vesta's, as well as others in the inner region of the
belt. The 20 small asteroids (diameters 
km) form a bridge
in proper orbital element space between 4 Vesta and the 3:1
Kirkwood gap at 2.5 AU, a region of dynamic instability from where
the meteorites are perturbed into Earth-crossing orbits
(Figure 2).
These findings strongly suggest that ejecta fragments from impacts on Vesta have, after gravitational perturbations and collisions, wended their way toward the 3:1 Kirkwood Gap, which has been shown by Wisdom [1985] to provide a probable source for perturbing objects into Earth-crossing orbits. The identifying signature of these Vestalettes is the inter-electronic transition between d-orbital electrons in the M1 site in orthopyroxene minerals. The spectral reflectance of basaltic achondrite meteorites in the laboratory is unique, as are the reflectance spectra of these asteroids observed at the telescope. These observations provide the experimental facts from which further modeling of collisional and orbital evolution will be developed.