(a) In cases where a major Federal action remains to occur, supplemental documentation may be required for previously prepared EAs or EISs under the following circumstances:

(1) If substantial changes are made to the proposed action that are relevant to environmental concerns; or

(2) There are significant new circumstances or information relevant to environmental concerns and bearing on the proposed action and its impacts; or

(3) NASA determines that the purposes of NEPA will be furthered by doing so.

(b) The preparation of a supplemental EA or EIS shall be undertaken using the same procedural requirements set forth in 40 CFR 1501.5 or 40 CFR part 1502, as applicable; however, in the event a supplement to an EIS is required, scoping shall not be required unless, at NASA's discretion and in consideration of the factors and requirements of 40 CFR 1501.9, it is determined to be necessary or would otherwise further the purposes of NEPA.

(c) When it is unclear if an EA or EIS supplement is required, NASA may prepare a Supplement Analysis.

(1) The Supplement Analysis will discuss the circumstances that are pertinent to deciding whether to prepare a supplemental EA or EIS.

(2) The Supplement Analysis will contain sufficient information for NASA to determine whether:

(i) An existing EA or EIS should be supplemented;

(ii) A new EA or EIS should be prepared; or

(iii) No further NEPA documentation is required.

(3) NASA shall make the determination and the related Supplement Analysis available to the public for information.

(d) When applicable, NASA shall incorporate the determination and supporting Supplement Analysis made under paragraph (b) of this section, into the administrative record related to the action that is the subject of the EA or EIS supplement or determination.