Type-S asteroid
Hewitt told SPACE.com that the risk analysis is being conducted in response to a formal access request from Japan’s ISAS. Asteroid 1998 SF36 has been identified and categorized into a type-S body. That is, based on current Earth-based spectral analysis, the rocky mini-world is an undifferentiated metamorphosed asteroid.
"Despite the perceived low risk and absence of trade implications, public consultation may be undertaken because of the likely public interest and concern with the proposal. This risk analysis is being coordinated in consultation with Environment Australia," Hewitt told SPACE.com.
"Because detailed risk analyses into sample returns from planetary satellites and small solar system bodies have already been undertaken, the primary role of our risk analysis is to review and adapt this risk analysis, as appropriate, to ensure Australia's quarantine concerns are addressed," Hewitt said.
Factors considered
Hewitt said that factors considered in the analysis include:
- Whether liquid water, energy sources or organic matter, which are necessary for life, are present on the asteroid (all indications are that the asteroid has none of these);
- Extremes of temperature and radiation exposure (both high temperatures and prolonged radiation levels indicates that any life, if it ever existed on the asteroid, is unlikely to exist now);
- The lack of evidence of life forms in meteorites that enter Earth's atmosphere daily; and
- The likelihood of an extraterrestrial life form surviving in an Earth environment;
In addition to the above factors, Hewitt added, Biosecurity Australia also has to consider the significance of evidence that cross-contamination of asteroids with material from other sources occurs. Also, the group will consider environmental exposure with the sample material at the landing site should the sample container breaks open on impact, say from failure of the sample capsule’s parachute to deploy.
Lastly, Biosecurity Australia will delve into the effects of extraterrestrial microorganisms on established microbial communities, if such organisms do exist, and whether such biology could find an eco-niche here on Earth suitable for growth.
Prudent policy
"Although the overall risk of adverse effects from a returned sample from an type S undifferentiated metamorphosed asteroid is likely to be extremely low to negligible, there are still some gaps in the information necessary to accurately determine that risk. Although available data will continue to expand over time, much of the information required will only be obtained by sample return missions. Until such additional information is available, it may be prudent to consider appropriate risk management procedures for return samples from small Solar System bodies," Hewitt said.
The risk analysis currently being undertaken by Biosecurity Australia, Hewitt said, will consider what, if any, appropriate risk management procedures are necessary especially in the event of a breach of the sample container.
The draft risk analysis is going through its final stages of development and hopefully should be available for public comment in a few months, Hewitt said.
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