  In February 15 2013 a medium-sized meteoroid impacted the atmosphere in the
region of Chelyabinsk, Russia. After its entrance to the atmosphere and after
travel by several hun- dred of kilometers the body exploded in a powerful event
responsible for physical damages and injured people spread over a region
enclosing several large cities. We present in this letter the results of a
preliminary reconstruction of the orbit of the Chelyabinsk meteoroid. Using
evidence gathered by one camera at the Revolution Square in the city of
Chelyabinsk and other videos recorded by witnesses in the close city of
Korkino, we calculate the trajectory of the body in the atmosphere and use it
to reconstruct the orbit in space of the meteoroid previous to the violent
encounter with our planet. In order to account for the uncertainties implicit
in the determination of the trajectory of the body in the atmosphere, we use
Monte Carlo methods to calculate the most probable orbital parameters. We use
this result to classify the meteoroid among the near Earth asteroid families
finding that the parent body belonged to the Apollo asteroids. Although
semimajor axis and inclination of the preliminary orbit computed by us are
uncertain, the rest of orbital elements are well constrained in this
preliminary reconstruction.
