NASA’s Use of Nuclear Power Sources in Mars 2020 Mission

January 24, 2020

The National Environmental Policy Act (NEPA) requires federal agencies such as NASA and the FAA to assess the environmental effects of their major federal actions.  Federal agencies must,

include in every recommendation or report on proposals for legislation and other major Federal actions significantly affecting the quality of the human environment, a detailed statement by the responsible official on—

(i) the environmental impact of the proposed action,

(ii) any adverse environmental effects which cannot be avoided should the proposal be implemented,

(iii) alternatives to the proposed action,

(iv) the relationship between local short-term uses of man’s environment and the maintenance and enhancement of long-term productivity, and

(v) any irreversible and irretrievable commitments of resources which would be involved in the proposed action should it be implemented.

Agencies must review the effects of their actions on the human environment.  Is it safe to assume that outer space is not a human environment?
NASA issued a notice on January 24, pursuant to NEPA and the regulations that implement NEPA:
NASA announces the availability of the Final Supplemental Environmental Impact Statement for the Mars 2020 Mission (Supplemental EIS). NASA has prepared the Final SEIS which, in accordance with CEQ NEPA Regulations, provides responses to comments and incorporates associated changes resulting from the public and agency review of the Draft SEIS published in October 2019. The Final SEIS provides updated information related to the potential environmental impacts associated with the proposed Mars 2020 mission.
This Final SEIS addresses NASA’s plan to use a nuclear power source for its Mars 2020 mission:
The updated information is pertinent to the consequence and risk analyses of potential accidents which could occur during the launch phases of the mission. Although the probability of such accidents occurring is extremely small, it is possible that under certain conditions an accident could result in a release of plutonium dioxide from the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) into the environment. The MMRTG is a critical component of the Mars 2020 rover; it would enable the Mars 2020 rover mission to undertake a much broader scope of scientific discovery by providing a continuous supply of electrical power and temperature control to the Mars 2020 rover while on the surface of Mars. The Mars 2020 mission would launch the spacecraft onboard an Atlas V launch vehicle from the Cape Canaveral Air Force Station (CCAFS), Brevard County, Florida during the summer of 2020. Additional information about the mission may be found on the internet at: https://mars.nasa.gov/mars2020/.