Interplanetary contamination

Interplanetary contamination refers to biological contamination of a planetary body by a space probe or spacecraft, either deliberate or unintentional.

There are two types of interplanetary contamination:

  • Forward contamination is the transfer of life and other forms of contamination from Earth to another celestial body.
  • Back contamination is the introduction of extraterrestrial organisms and other forms of contamination into Earth's biosphere. It also covers infection of humans and human habitats in space and on other celestial bodies by extraterrestrial organisms, if such organisms exist.

The main focus is on microbial life and on potentially invasive species. Non-biological forms of contamination have also been considered, including contamination of sensitive deposits (such as lunar polar ice deposits) of scientific interest.[1] In the case of back contamination, multicellular life is thought unlikely but has not been ruled out. In the case of forward contamination, contamination by multicellular life (e.g. lichens) is unlikely to occur for robotic missions, but it becomes a consideration in crewed missions to Mars.[2]

Current space missions are governed by the Outer Space Treaty and the COSPAR guidelines for planetary protection. Forward contamination is prevented primarily by sterilizing the spacecraft. In the case of sample-return missions, the aim of the mission is to return extraterrestrial samples to Earth, and sterilization of the samples would make them of much less interest. So, back contamination would be prevented mainly by containment, and breaking the chain of contact between the planet of origin and Earth. It would also require quarantine procedures for the materials and for anyone who comes into contact with them.

  1. ^ S.T. Shipley; P.T. Metzger & J.E. Lane (27 October 2014). "Lunar Cold Trap Contamination by Landing Vehicles" (PDF). Earth and Space 2014 - Proceedings of the 14th Biennial ASCE Conference on Engineering, Science, Construction, and Operations in Challenging Environments.
  2. ^ Purdue University Staff (27 February 2018). "Tesla in space could carry bacteria from Earth". phys.org. Retrieved 28 February 2018.