  We have extended our earlier work on space weathering of the youngest
S-complex asteroid families to include results from asteroid clusters with ages
<10^6 years and to newly identified asteroid pairs with ages <5x10^5 years. We
have identified three S-complex asteroid clusters with ages in the range
10^{5-6} years. The average color of the objects in these clusters agree with
the prediction of Willman et al., 2008. SDSS photometry of the members of very
young asteroid pairs with ages <10^5 years was used to determine their
taxonomy. The average color of the S-complex pairs is PC_1=0.49+/-0.03, over
5-sigma redder than predicted by Willman et al., 2008. Therefore, the most
likely pair formation mechanism is gentle separation due to YORP spin-up
leaving much of the aged and reddened surface undisturbed. In this case our
color measurement allows us to set an upper limit of ~64% on the disturbed
surface portion. Using pre-existing color data and our new results for the
youngest S-complex asteroid clusters we have extended our space weather model
to explicitly include the effects of regolith gardening and fit separate
weathering and gardening characteristic timescales of tau_w=960+/-160My and
tau_g=2000+/-290My respectively. The first principal component color for fresh
S-complex material is 0.37+/-0.01 while the maximum amount of local reddening
is 0.33+/-0.06. Our first-ever determination of the gardening time is in stark
contrast to our calculated gardening time of tau_g~270My based on main belt
impact rates and reasonable assumptions about crater and ejecta blanket sizes.
A possible resolution for the discrepancy is through a `honeycomb' mechanism in
which the surface regolith structure absorbs small impactors without producing
significant ejecta. This mechanism could also account for the paucity of small
craters on (433) Eros.
