OSIRIS REx Sample Return Doesn’t Pose a Risk to Earth’s Biosphere
When OSIRIS-REx returns a sample of the asteroid Bennu to Earth on September 24, 2023, it will kick off a carefully orchestrated retrieval process. One thing the retrieval team won’t need to worry about is protecting Earth and its inhabitants from the sample.
“The OSIRIS-REx sample return is classified as an unrestricted Earth-return so there don’t need to be any protocols put in place from a public safety and Planetary Protection perspective,” said Nick Benardini, Planetary Protection officer. “Due to this type of target body having only some of the key formational and evolutionary organic molecules necessary for life, there is no chance that the sample from Bennu could contain living organisms.”
OSIRIS-REx is the first-ever U.S. mission to bring an asteroid sample back to Earth and the rocks and dust collected from Bennu’s surface in 2020 will offer scientists a window into the past when the Sun and planets were forming about 4.5 billion years ago
In contrast, the Mars Sample Return (MSR) that is projected to occur in 2033 or later will be classified as a restricted Earth-return, which means Planetary Protection protocols will be in place.
“With MSR, there is a concern about the potential spread of extraterrestrial life or bioactive molecules that could result in adverse changes to the Earth’s biological environment,” said Benardini.
As such, past and recent studies on return samples from Mars conducted by Subject Matter Experts and public health and safety biohazard experts recommend caution.
“We will be working alongside our U.S. government interagency and international partners to take every precaution necessary to adequately and safely prepare for MSR so that we can effectively mitigate the level of backward Planetary Protection risk,” said Benardini.
Learn more about the OSIRIS REx and Mars Sample Return Missions and contact Benardini for additional information.
Unrestricted Earth-Return Vs. Restricted Earth-Return
An unrestricted Earth-return is an Earth-return mission from a body “deemed by scientific opinion to have no indigenous life forms,” which means there are no threats to our planet or its inhabitants.
A restricted Earth-return is an Earth-return mission from a body with a significant risk of backward contamination, which refers to the release of extra-terrestrial material into the Earth’s biosphere. This type of return will require the containment of any unsterilized samples that are collected and returned to Earth.
NPR 8715.24, Planetary Protection Provisions for Robotic Extraterrestrial Missions and NSA Technical Standard 8719.27, Chapter 5.4, Restricted Earth-Return (V) Implementation Requirements detail the required steps to take to prevent backward contamination for restricted Earth-returns.