"Meteorites usually have considerable terrestrial contamination".
But they couldn't nail it because of terrestrial contamination.
The biggest problem was working out how to reliably remove terrestrial contamination from the team's spectra.
"It's so difficult to eliminate terrestrial contamination," he says, "especially when you get things that look just like Earth".
The CI-like chondrites show a broad mass loss from 0 to 200 °C that is distinct from the CI chondrites and probably reflects terrestrial contamination.
Through examination of the carbonaceous materials, the appropriate analytical processes for sample transportation and handling were optimized to minimize sample damage and terrestrial contamination.
It is therefore difficult to conclude, based on the data, whether these Hayabusa category 3 samples are terrestrial contamination or extraterrestrial materials.
Heating the samples to 300 °C removes not only the terrestrial contamination but also, as demonstrated by the TGA results, the extra-terrestrial interlayer H2O.
The difficulties in handling and/or processing of these small carbonaceous samples without introducing terrestrial contamination resulted in the collection of insufficient information from the first examination to explore the origin of category 3 particles.
Planetary protection aims to protect celestial bodies from terrestrial contamination and to protect the Earth environment from potential biological contamination carried by returned samples or space systems that have been in contact with an extraterrestrial environment.
After the FT-IR measurement at ESCuC/JAXA, NanoSIMS analysis was performed at Kochi Institute for Core Sample Research of JAMSTEC to measure stable isotope ratios of hydrogen (δD), carbon (δ13C), and nitrogen (δ15N) in order to discriminate the particle origins: extraterrestrial material vs. terrestrial contamination (Ito et al. 2014).
