  We determine the absolute magnitude (H) distribution (or size-frequency
distribution, SFD; $N(H) \propto 10^{\alpha H}$ where $\alpha$ is the slope of
the distribution) for near-Earth objects (NEO) with $13<H<30$ and Asteroid
Retrieval Mission (ARM) targets with $27<H<31$ that were detected by the 1\st\
telescope of the Panoramic Survey Telescope and Rapid Response System -
Pan-STARRS1 (e.g. Kaiser et al. 2002, Kaiser 2004, Hodapp et al. 2004). The NEO
and ARM target detection efficiencies were calculated using the Greenstreet et
al. (2012) NEO orbit distribution. The debiased Pan-STARRS1 NEO absolute
magnitude distribution is more complex than a single slope power law - it shows
two transitions - at H$\sim$16 from steep to shallow slope, and in the
$21<H<23$ interval from a shallow to steep slope, which is consistent with
other recent works (e.g. Mainzer et al. 2011c, Brown et al. 2013, Harris and
D`Abramo 2015). We fit $\alpha = 0.48\pm0.02$ for NEOs with $13<H<16$, $\alpha
= 0.33\pm0.01$ for NEOs with $16<H<22$, and $\alpha = 0.62\pm0.03$ for the
smaller objects with $H>22$. There is also another change in slope from steep
to shallow around H=27. The three ARM target candidates detected by Pan-STARRS1
in one year of surveying have a corrected SFD with slope $\alpha =
0.40^{+0.33}_{-0.45}$.
  We also show that the window for follow up observations of small
(H$\gtrsim$22) NEOs with the NASA IRTF telescope and Arecibo and Goldstone
radars are extremely short - on order of days, and procedures for fast response
must be implemented in order to measure physical characteristics of small
Earth-approaching objects. CFHT's MegaCam and Pan-STARRS1 have longer observing
windows and are capable of following-up more NEOs due to their deeper limiting
magnitudes and wider fields of view.
