The National Environmental Policy Act

The National Environmental Policy Act

First published Summer 2011, Crosslink® magazine.


The National Environmental Policy Act (NEPA), signed into law on January 1, 1970, requires federal agencies to study and document the effects of their actions on the environment. Potential impacts on human health and safety; air, soil, and water quality; ecosystems; cultural and historical resources; land use; and socioeconomics resulting from the proposed action (and all viable alternatives) must be considered in an environmental assessment conducted by qualified experts. The assessment involves comprehensive analyses and documentation that is made available to the public during a 30-day review period. If impacts are determined to be significant, efforts must be made to minimize them. If this is not possible, an environmental impact statement must be prepared. The impact statement requires a 45-day public review along with public hearings and meetings with regulatory agencies, public officials, and affected groups. NEPA not only involves issues that are currently regulated by the federal government, but also extends to unforeseen impacts that a federal agency could prohibit or regulate.

Air Force space-related activities subject to NEPA requirements include the processing and launching of spacecraft and launch vehicles, construction and operation of ground systems, and the disposal of spacecraft, launch vehicles, and associated equipment. Aerospace assists the Air Force in fulfilling these requirements by quantifying the environmental impacts of satellite and missile launches, interpreting regulations to help ensure final documents and proposed actions are within applicable requirements, and assessing potential impacts from ground-based activities.

Ground-based activities that could affect the environment include the installation and operation of new antenna systems, terminals, and associated infrastructure. Detailed knowledge of planned construction, demolition, transportation, and operation of a proposed ground system is required to determine potential impacts to the ecosystem as well as to the health and safety of humans and wildlife. Cumulative effects—that is, the total impact of the proposed action considered together with other past, present, and reasonably foreseeable future actions—must be assessed. Many factors can combine to complicate the analysis. For example, the assessment of cumulative health and safety impacts of nonionizing radiation produced by a new ground antenna must include the nonionizing radiation emitted by all other antennas in the region of influence. Effects of pollutants that could potentially reach local water supplies and aquifers must be studied from chemical, biological, and engineering perspectives.

Proposed launch and ground station activities can have significant effects on endangered species. Many launch facilities and ground systems are located in remote coastal regions and on islands, which tend to contain sensitive habitats such as wetlands and coral reefs. Noise caused by construction, launch, and daily operations must also be considered. NEPA also requires that impacts from reentering spacecraft be studied.

NEPA also covers atmospheric effects, which have been a primary focus for many years. Short-term pollution from construction must be estimated, as well as long-term emissions from space system operations, to assess compliance with applicable air quality regulations. Launch vehicles can affect the atmosphere in many ways. For example, Aerospace has quantified global ozone depletion caused by the release of chlorine into the stratosphere from perchlorate-based solid-fueled rockets. Launch vehicles also release a large quantity of greenhouse gases and other species (in this case, nongaseous products of the exhaust such as black carbon soot and metal particulates) that can interact with existing atmospheric gases. Because these gases are released in all layers of the atmosphere, they can have dramatically different effects as compared with gases released on the ground. Aerospace calculates the amount of carbon dioxide generated by Air Force space launches and can also evaluate the effects of other pollutants that may soon be regulated.

Launch activities also can produce sonic booms that can affect the surrounding environment. Sonic booms can occur not only from launch operations but also from spacecraft and debris reentering the atmosphere from space. Sonic booms over the ocean penetrate below the surface and can affect the deep ocean environment as well. The process is not well understood, and the effect on biological systems has not been quantified. Aerospace is studying these impacts.

Many of the propellants used in launch vehicles and spacecraft—such as ammonium perchlorate, nitrogen tetroxide, and hydrazine and its derivatives—are toxic or corrosive. Others contain cryogenic materials. A small number of spacecraft also use radioactive material in orbit. NEPA requires that the environmental and human health risks from the routine handling, storage, and use of these materials be considered as well as the effects of unintentional release into the environment. Because launch operations are not always successful, appropriate mitigation and verification methods must be identified and documented in an environmental assessment or impact statement.


NEPA documentation addresses an extensive set of considerations that encompass nearly the entire sphere of proposed Air Force space activities. Aerospace is actively involved in supporting the Air Force with NEPA compliance in all areas of potential concern, including anticipation of future requirements and related mitigation planning and implementation.

—Mary Ellen Vojtek, Charles Griffice, John DeSain, and Brian Brady

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