Mars Science Laboratory

Draft Environmental Impact Statement (DEIS) 

NASA is proposing to launch a mission in the fall of 2009 that would land a large, highly capable rover on Mars. 

The proposed Mars Science Laboratory rover would carry a suite of science instruments designed to gather detailed 

information on the past and present habitability of Mars. The proposed mission would demonstrate NASA’s 

capability to deliver more capable science instruments to Mars and operate in scientifically promising regions of 

Mars over a wide latitude range. The proposed Mars Science Laboratory rover would be capable of visiting and 

investigating multiple, geologically diverse sites by being able to drive for several miles and operate for one 

Martian year (683 Earth days, a little less than 2 Earth years). A new, more precise landing technique would give 

the rover access to key sites of scientific interest. 

The Mars Science Laboratory DEIS addresses the potential environmental impacts from both a successful launch 

and from various postulated launch accidents. This fact sheet summarizes some of the key points made in the 

DEIS. 

The NEPA Process 

The National Environmental Policy Act (NEPA) 

requires federal agencies to prepare an 

Environmental Impact Statement (EIS) for major 

federal actions that may significantly affect the 

quality of the human environment. Federal agencies 

consider potential environmental impacts of their 

proposed actions before deciding whether and how to 

proceed. NASA developed a Draft Environmental 

Impact Statement (DEIS) as part of the process for 

deciding whether to continue with the preparations 

for a Mars Science Laboratory mission. 

Alternatives Considered in the DEIS 

Proposed Action (Alternative 1, Radioisotope 

Power System-Powered Rover): Under this 

alternative, NASA would implement the proposed 

mission using a Multi-Mission Radioisotope 

as its source of electrical power. This rover would be 

Thermoelectric Generator (MMRTG) power system 

capable of performing all the science experiments 

planned for the mission for an entire Martian year 

over a wide latitude range on Mars (60o

 North 

latitude to 60o

 South latitude). 

Alternative 2 (Solar-Powered Rover): Under this 

alternative, NASA would implement an alternative 

Mars Science Laboratory mission based on a rover 

using solar arrays as its source of electrical power. 

The solar-powered rover would be capable of 

performing all the science experiments planned for 

the mission for a full Martian year at 15o

 N latitude. 

Such a rover could accomplish the minimum science 

objectives over a latitude range of approximately 5o 

North to about 20o

 North latitude. At other latitudes 

a solar-powered rover would be unable to generate 

sufficient power for the rover to survive the extreme 

cold temperatures, and thus would not be able to 

survive for an entire Martian year. 

Alternative 3 (No Action): Under this alternative, 

NASA would discontinue preparations for the 

proposed Mars Science Laboratory mission and the 

spacecraft would not be launched. The No-Action 

Alternative would not accomplish any science or 

technology objectives of NASA’s Mars Exploration 

Program. 
Potential Environmental Impacts 

The potentially affected environment for the launch 

of the Mars Science Laboratory mission includes 

areas on or near the Atlas V launch pad at NASA’s 

Kennedy Space Center, the Cape Canaveral Air 

Force Station, Florida and the environment in 

general. Environmental impacts are not considered 

for Alternative 3 since the proposed launch would not 

occur. 

Successful Launch: 

The environmental impacts associated with 

successfully implementing either the Proposed 

Action (Alternative 1) or Alternative 2 would be 

associated principally with the exhaust emissions 

from the launch vehicle. These effects would 

include short-term impacts on air quality from 

the exhaust cloud at and near the launch pad, and 

short-term acidic deposition on the vegetation 

and surface water bodies at and near the launch 

complex. These effects would be transient and 

there would represent neither long-term nor 

cumulative impacts to the environment. Some 

short-term ozone degradation would occur along 

the flight path of the vehicle but these effects 

would be transient and neither long-term nor 

cumulative impacts would be expected to the 

ozone layer. 

Non-Radiological Impacts of a Launch Accident: 

The environmental impacts associated with a launch 

vehicle accident that does not release radiological 

material are the same for Alternative 1 and 

Alternative 2. Possible impacts include a spill during 

fueling operations or a launch vehicle failure. If a 

spill of liquid propellant were to occur, operations 

personnel would remotely shut down the fuel loading 

system to minimize the amount of fuel released. A 

launch vehicle failure during the early ascent phase 

of flight could release propellants from the Atlas V 

and the Mars Science Laboratory spacecraft; 

however, burned propellants chemically resemble 

those from a normal launch and would not reach 

levels that could threaten public health. Debris 

would likely fall in areas already cleared of personnel 

or members of the public by range safety -- on or 

near the launch pad or into the Atlantic Ocean. 

Radiological Impacts of a Launch Accident: 

To support the NEPA decision making process, the 

Department of Energy (DOE) prepares a nuclear risk 

assessment for any proposed launch of radioisotope 

powered missions. 

NASA and DOE examine many possible accident 

scenarios based on extensive data from past launches, 

tests and modeling. These data are used to simulate 

potential accident conditions and to develop a 

detailed assessment of the launch system’s failure 

modes. The DOE risk assessment for the Mars 

Science Laboratory mission covers accident scenarios 

from pre-launch to post-launch and through 

commanding the spacecraft onto its flight path to 

Mars. 

The DOE assessment indicates which launch 

accidents could potentially result in a release of 

radioactive material. It also predicts the amount, 

particle size and movement of any material that could 

be released and estimates potential radiation 

exposures and health effects to the general public. 

The risk assessment identifies potential launch 

accidents that while not expected, could result in a 

release of plutonium dioxide in the launch area, 

southern Africa following suborbital reentry, or other 

global locations following orbital reentry. However, 

in each of these regions an accident resulting in a 

release of plutonium dioxide is unlikely (i.e. the 

estimated probability of such an accident in each 

region ranges from 1 in several hundred to 1 in 

several thousand). Accidents which would result in 

impacts in the Atlantic Ocean would not result in a 

release of plutonium dioxide. Failures occurring 

after the spacecraft escapes the Earth’s gravity field 

would not result in a release of plutonium dioxide on 

Earth. 

What do results of the DOE Risk Assessment 

show? 

o For the overall mission, there is a 1 in 220 chance 

that a failure could result in a release of 

plutonium. 

o There is a 1 in 420 chance of a failure resulting in 

a release of plutonium dioxide in the launch area. 
o The chances of any radiological impact occurring 

as the result of launch of the proposed Mars 

Science Laboratory mission is small, less than 

0.5 percent. 

o For the overall mission given an accident with a 

release of plutonium the maximally exposed 

individual would be expected to only receive a 

dose over a period of 50 years approximately 

equal to that received by the average citizen from 

natural background radiation in one year. 

Radiological Contingency Planning: 

What’s Next? 

For any launch of radioactive materials, a 

comprehensive set of radiological response plans, 

which are fully coordinated with local, state, and 

federal representatives, is developed by NASA prior 

to launch to ensure that any launch accident could be 

met with a thoroughly tested response. NASA’s 

plans are developed in accordance with the National 

Response Plan and applicable state and county 

emergency plans, in coordination with federal 

agencies responsible for emergency response, the 

State of Florida, Brevard County, and local launch 

site response organizations. At the time of launch, 

emergency response personnel and equipment will be 

pre-deployed both on-site and in surrounding 

communities to continuously monitor the air to detect 

a potential release of radioactive material following a 

launch accident. The selection of the types and 

capabilities of response personnel and equipment is 

based on a radiological contingency planning effort 

that was initiated early and continues throughout the 

mission planning process. 

The public is welcome to comment on the information in the DEIS; the comment period ends on October 23, 2006. 

Comments will be addressed in the Mars Science Laboratory Final Environmental Impact Statement scheduled for 

completion and released in November 2006. NASA’s Record of Decision selecting one of the Alternatives is 

planned for issue in December 2006. 

For More Information 

Mark R. Dahl 

Science Mission Directorate, NASA Headquarters 

Washington, DC 20546 

(202)-358-4800 

mep.nepa@hq.nasa.gov