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2. Biohazard and Back Planetary Protection

2005: IVA-1C
2010: 1B
Priority: High

Investigation: Determine if the martian environments to be contacted by humans are free, to within acceptable risk standards, of biohazards that may have adverse effects on the crew who may be directly exposed while on Mars and on other terrestrial species if uncontained martian material is returned to Earth. Note that determining that a landing site and associated operational scenario is sufficiently safe is not the same as proving that life does not exist anywhere on Mars.

biohazards and cross-contamination
Some of the most important things to prepare for and try to avoid when considering a manned mission to Mars are biohazards and cross-contamination. Image credit: SETI, (

Back Planetary Protection refers to avoiding introducing to Earth organisms that may be present in samples or particles returned from extraterrestrial locations (in this case, from Mars). As seen in the Apollo missions, it is impossible to keep all surfaces clean of dust. While robotic missions could avoid bringing back unwanted particles by “breaking the chain of contact”, on a crewed mission it would be impossible to avoid human contact with Martian dust. To ensure the safety of the crew and to prevent the contamination of Earth, it is necessary to determine in advance whether or not the dust is biologically hazardous. Knowledge of Martian regolith and air-borne dust would aid in understanding, explaining, and managing any possible human health risk associated with Martian dust and regolith.

Click on the expandable links below to see the 2005 and 2010 versions of this investigation.

2005 Version of Investigation (old version)

2010 Version of Investigation (current version)

While there has been ongoing research in this area, none of the measurements in this investigation have been fully satisfied. Scientists agree the best way to ensure that there is no life in Martian regolith at a proposed landing site is through sample return. The following resources describe protocols and priorities for sample return missions.

  • Rummel, J.D., M.S. Race, D. L. DeVincenzi, P. J. Schad, P. D. Stabekis, M. Viso, and S. E. Acevedo, editors (2002). “A Draft Test Protocol for Detecting Possible Biohazards in Martian Samples Returned to Earth [NASA=CP-20-02-211842],” NASA Ames Research Center, Moffett Field, CA.
  • MEPAG ND-SAG (2008). “Science Priorities for Mars Sample Return.” Unpublished white paper, 73 p, posted March 2008 by the Mars Exploration Program Analysis Group (MEPAG) at
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