  Hydrophobic silica aerogels with ultra-low densities have been designed and
developed as cosmic dust capture media for the Tanpopo mission which is
proposed to be carried out on the International Space Station. Glass particles
as a simulated cosmic dust with 30 \mu m in diameter and 2.4 g/cm^3 in density
were successfully captured by the novel aerogel at a velocity of 6 km/s.
Background levels of contaminated DNA in the ultra-low density aerogel were
lower than the detection limit of a polymerase chain reaction assay. These
results show that the manufactured aerogel has good performance as a cosmic
dust collector and sufficient quality in respect of DNA contamination. The
aerogel is feasible for the biological analyses of captured cosmic dust
particles in the astrobiological studies.
