TABLE 2.1 COSPAR Planetary Protection Policy Categories for Solar System Bodies and Types of Missions (and Specific Requirements for Mars)








Mission type

Any but Earth return

(flyby, orbiter, lander)

Any but Earth return

(flyby, orbiter, lander)

No direct contact

(flyby, some orbiters)

Direct contact

(lander, probe, some orbiters)

Target body

Venus; Moon; undifferentiated, metamorphosed asteroids; others TBD

Comets, carbonaceous chrondite asteroids, Jupiter, Saturn, Uranus, Neptune, Pluto/Charon, Kuiper Belt objects, others TBD

Mars, Europa, others TBD

Mars, Europa, others TBD

Degree of concern


Record of planned impact probability and contamination control measures

Limit on impact probability

Passive bioload control

Limit on probability of non-nominal impact

Limit on bioload (active control)

Representative range of requirements


Documentation only: planetary protection plan, pre-launch report, post-launch report, post-encounter report, end-of-mission report

Documentation (Category II) plus contamination control, organics inventory (as necessary); implementing procedures such as trajectory biasing, clean room, bioload reduction (as necessary)

Mars orbiters will not be required to meet orbital lifetime requirementsb if they achieve bioburden levels equivalent to the Viking lander pre-sterilization total bioburden.

Documentation (Category II) plus Pc analysis plan, microbial reduction plan, microbial assay plan, organics inventory; implementing procedures such as trajectory biasing, clean room, bioload reduction, partial sterilization of contacting hardware (as necessary), bioshield monitoring of bioload via bioassay

aA special region is defined as a region within which terrestrial organisms are likely to propagate, or a region that is interpreted to have a high potential for the existence of extant martian life forms. Given current understanding, this definition applies to regions where liquid water is present or may occur. Specific examples include but are not limited to (1) subsurface access in an area and to a depth where the presence of liquid water is probable, (2) penetrations into the polar caps, and (3) areas of hydrothermal activity.

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