(a) In cases where a major Federal action remains to occur, supplemental documentation may be required for previously prepared environmental assessments or environmental impact statements under the following circumstances:
(1) If substantial changes are made to the proposed action that are relevant to environmental concerns.
(2) There are significant new circumstances or information relevant to environmental concerns and bearing on the proposed action and its impacts.
(3) NASA determines that the purposes of NEPA will be furthered by doing so.
(b) The preparation of a supplemental environmental assessment or environmental impact statement shall be undertaken using the same procedural requirements as the initial document however, in the event a supplement to an environmental impact statement is required, public scoping shall not be required unless, at NASA's discretion, it is determined to be necessary or would otherwise further the purposes of NEPA.
(c) When it is unclear if an environmental assessment or environmental impact statement supplement is required, NASA may prepare a written reevaluation.
(1) The written reevaluation will discuss the circumstances that are pertinent to deciding whether to prepare a supplemental environmental assessment or environmental impact statement.
(2) The written reevaluation will contain sufficient information for NASA to determine whether:
(i) An existing environmental assessment or environmental impact statement should be supplemented;
(ii) A new environmental assessment or environmental impact statement should be prepared; or
(iii) No further NEPA documentation is required.
(3) NASA shall make the determination and the related written reevaluation available to the public for information.
(d) When applicable, NASA shall incorporate the determination and supporting written reevaluation into the administrative record related to the action that is the subject of the environmental assessment or environmental impact statement supplement or determination.