91. National Security Decision Memorandum 3331


  • The Secretary of Defense
  • The Director of Central Intelligence


  • Enhanced Survivability of Critical U.S. Military and Intelligence Space Systems

The President has expressed concern regarding the emerging Soviet anti-satellite capability and the possible threat to critical U.S. space missions this implies. He considers preserving the right to free use of space to be a matter of high national priority. The U.S. trend toward increasing exploitation of space for national security purposes such as strategic and tactical reconnaissance, warning, communications, and navigation—combined with the simultaneous trend toward a smaller number of larger, more sophisticated satellites—emphasizes the need for a reassessment of U.S. policy regarding survivability of critical military and intelligence space assets.

Policy for Survivability of Space Assets

The President has determined that the United States will continue to make use of international treaty obligations and political measures to [Page 385]foster free use of space for U.S. satellite assets both during peacetime and in times of crisis. However, to further reduce potential degradation of critical space capabilities resulting from possible interference with U.S. military and intelligence space assets, the President also considers it necessary to implement improvements to their inherent technical survivability. Such survivability improvements should supplement and reinforce the political measures, as well as extend the survivability of critical space assets into higher level conflict scenarios.

The survivability improvements in critical military and intelligence space assets should be predicated on the following U.S. objectives:

(1) Provide unambiguous, high confidence, timely warning of any attack directed at U.S. satellites;

(2) Provide positive verification of any actual interference with critical U.S. military and intelligence satellite capabilities;

(3) Provide sufficient decision time for judicious evaluation and selection of other political or military responses after the initiation of an attempt to interfere and before the loss of a critical military or intelligence space capability;

(4) Provide a balanced level of survivability commensurate with mission needs against a range of possible threats, including non-nuclear co-orbital interceptor attacks, possible electronic interference, and possible laser attacks;

(5) Substantially increase the level of resources needed by an aggressor to successfully interfere with critical U.S. military and intelligence space capabilities;

(6) Deny the opportunity to [1 line not declassified] U.S. military and intelligence space systems.

Planning for Improved Survivability

The President directs that efforts be initiated jointly by the Secretary of Defense and the Director of Central Intelligence to prepare an aggressive time-phased, prioritized action plan which will further develop and implement this policy framework. This plan should (1) place emphasis on short-term and intermediate-term measures to enhance the survivability of critical military and intelligence space capabilities against Soviet non-nuclear and laser threats at low altitudes and Soviet electronic threats at all altitudes, and (2) consider long-term measures which will provide all critical military and intelligence space systems with a balanced level of survivability commensurate with mission needs against all expected threats, including threats at higher altitudes.

Short/intermediate term measures for consideration in the plan should include, but not be limited to, the following capabilities:

[Page 386]

(1) [6 lines not declassified]

(2) [4½ lines not declassified]

(3) Contingency procedures/capabilities [1½ lines not declassified] attempted non-nuclear co-orbital interceptor attack. This should include needed command/control/communications improvements, as well as procedures for delegation of authority, where appropriate, and for periodic exercises to verify timely operation of the system.

(4) Encryption protection for command links of critical military and intelligence satellites.

Longer-term measures should provide balanced survivability for critical space capabilities against the full range of credible threats. The plan should detail the military and intelligence utilization of specific systems at various levels of potential conflict and should select survivability measures and implementation schedules for each critical military or intelligence satellite in accord with their scenario-related mission needs. The threats to be considered include threats of physical attack against satellites, either by non-nuclear or laser techniques; [2½ lines not declassified] Continued consideration should be given to protection against nuclear effects from events other than direct attack, for those space assets which support nuclear scenarios. This portion of the plan should consider measures necessary to enhance the survivability of both ground and spaceborne elements and should consider proliferation or back-up alternatives where appropriate, as well as active and passive measures.

The plan should develop a range of implementation schedule/funding profiles for Presidential consideration. An initial version of this plan should be submitted to the President no later than November 30, 1976.

Brent Scowcroft
  1. Source: Ford Library, NSC Institutional Files (H-Files), Box 66, NSDM 333 (1). Top Secret. Copies were sent to Kissinger, General Brown, and Lynn. Scowcroft forwarded the draft NSDM to Ford under a covering memorandum, July 5, with the recommendation that the President approve Scowcroft’s signing the NSDM. Ford initialed his approval. (Ibid.) This is the NSDM discussed in Scowcroft’s April 26 memorandum to Ford ( Document 80). The NSDM is also printed as Document 128 in Foreign Relations, 1969–1976, Vol. E–3, Documents on Global Issues, 1973–1976.