Mars 2020 has been designated Planetary Protection Category IVb, (subsystem level). Due to the presence of a radiothermal generator, heritage hardware from the Mars Science Laboratory is restricted from landing in sites where water, brine, or water-ice is suspected to be present, or could be induced, within 5 meters of the surface. In addition, the Mars 2020 SDT report concluded that the primary mission objective of exploring an ancient environment does not require the mission to access Special Regions, defined as locations where conditions could exceed a temperature of -25C and water activity of 0.5 at the same time. Because of this conclusion and the fact that the high MSL heritage in the engineering systems do not readily support the Category IVc classification that would accompany a mission that landed in a Special Region, Mars 2020 did not request a IVc designation and in fact is required to avoid landing in Special Regions. Additional information on this topic can be found in the Mars 2020 SDT Report, Section 8.4 [Mustard et al., 2013].
(updated June 9, 2015)