  The Asteroid Redirect Mission (ARM) under development by NASA is being
planned to collect a multi-meter boulder from a near-Earth asteroid (NEA), and
to bring it to the cis-lunar space in the mid-2020's for future study and
exploitation by a crewed mission. The MarcoPolo-M5 project is being proposed in
2016 for the M5 mission opportunity by ESA, to bring back to Earth a sample
from a very primitive D-type NEA.
  We aim to further characterize the physical properties of two optimal targets
for sample return space missions, the low-DeltaV NEAs (341843) 2008 EV5 and
(52381) 1993 HA. 2008 EV5 is the baseline target of ARM, but only one spectrum
of this object exists in the literature. 1993 HA is a very favourable target
for a space mission based on its dynamical properties: here we intend to assess
if it is a suitable target for MarcoPolo-M5.
  We obtained visible spectroscopy of 2008 EV5 with the FORS2 instrument at
ESO-VLT, at different rotational phases. We also obtained visible and
near-infrared spectroscopy of 1993 HA, using the EFOSC2 and SOfI instruments at
ESO-NTT. Visible photometry of 1993 HA was carried out within the IMPACTON
project at the Observatorio Astronomico do Sertao de Itaparica (Brazil).
  Our new observations are in agreement with the C-type classification of 2008
EV5. We obtained five visible spectra which do not show any variability within
the limits of noise, suggesting a homogeneous surface. We obtained the first
ever spectroscopic dataset for 1993 HA, finding a featureless, red-sloped
behaviour typical of D-types. We found that the synodic rotation period of 1993
HA is 4.107+-0.002 h. The derived lightcurve also suggests an elongated shape
(axis ratio a/b>=1.71). At this stage 1993 HA does indeed seem to be the most
favourable target for MarcoPolo-M5, though future observations are necessary to
study it further.
