  <abridged> NASA's Asteroid Redirect Mission (ARM) has been proposed with the
aim to capture a small asteroid a few meters in size and redirect it into an
orbit around the Moon. There it can be investigated at leisure by astronauts
aboard an Orion or other spacecraft. The target for the mission has not yet
been selected, and there are very few potential targets currently known. Though
sufficiently small near-Earth asteroids (NEAs) are thought to be numerous, they
are also difficult to detect and characterize with current observational
facilities. Here we collect the most up-to-date information on the smallest
known near-Earth asteroids to outline the properties of these small NEAs as
currently understood, in order to examine what the eventual ARM target might be
like. Observational biases certainly mean that our sample is not an ideal
representation of the true population of small NEAs. However our sample is
representative of the eventual target list for the ARM mission, which will be
compiled under very similar observational constraints unless dramatic changes
are made to the way near-Earth asteroids are searched for and studied.
  We find that the typical rotation period is 40 minutes. The mean and median
axis ratios were 1.43 and 1.29. Rotation rates much faster than the spin
barrier are seen, reaching below 30 seconds, and implying that most of these
bodies are monoliths. Non-principal axis rotation is uncommon. Axial ratios
often reach values as high as two, though no undisputed results reach above
three. We find little correlation of axis ratio with size. The most common
spectral type in the sample of small NEAs is S-type (> 90%), with only a
handful of C and X types known.
