The possibility that some meteoroids in the size range 1 – 20 meters are rubble piles i.e .
assembles of boulders of various sizes held together only by small van der Waals forces , is investigated .
Such meteoroids are expected to start disrupting into individual pieces during the atmospheric entry at very low dynamic pressures of \sim 25 Pa , even before the onset of ablation .
The heterogeneous bodies as Almahata Sitta ( asteroid 2008 TC _ { 3 } ) and Benešov are primary candidates for rubble piles .
Nevertheless , by analyzing the deceleration , wake , and light curve of the Benešov bolide , we found that the meteoroid disruption started only at a height of 70 km under dynamic pressure of 50 kPa .
No evidence for a very early fragmentation was found also for the Chelyabinsk event .