without requiring a maneuver. Unlike the vast majority of flight rules, which place safety first and then allow exceptions in limited cases, this flight rule places mission needs first and requires those who provide the collision warning to prove that action needs to be taken.

Future shuttle missions that support the ISS will have a limited ability to maneuver. NASA Flight Rule C4.3.2–1, Space Station Translation Maneuvers During Joint Shuttle Operations, states that debris avoidance maneuvers will not be performed during docked operations. In addition, NASA reports that maneuvers will probably not be performed when the orbiter is undocked but is involved in assembly operations (Reeves, 1997).

Finding. NASA Flight Rules A4.1.3–6 and C4.3.2–1 appear to place mission success ahead of flight safety. The mechanism for making trade-offs between success and safety is not explicit.


Recommendation 6. NASA has recently documented and provided collision avoidance requirements to the DOD. NASA and the DOD should work to satisfy these requirements, to identify impending changes to the SSN that will affect debris tracking, and to identify changes that would improve the SSN’s ability to track smaller objects that pose a hazard for crewed spacecraft.

Recommendation 7. NASA should re-examine Flight Rules A4.1.3–6 and C4.3.2–1 and consider restating them to establish when a maneuver is mandatory for safety reasons.


Barker, W.N. 1996. Space Station Debris Avoidance Study. Initial Report. Kaman Sciences Report KSPACE 96–114. Colorado Springs, Colo.: Kaman Sciences Corporation.

Barker, W.N. 1997. Space Station Debris Avoidance Study. Final Report. Kaman Sciences Report KSPACE 97–47. Colorado Springs, Colo.: Kaman Sciences Corporation.

Kessler, D.J. 1996. Private communication to Robert Culp, member of the National Research Council Committee on Space Station Meteoroid/Debris Risk Management, April 17, 1996.

Loftus, J.P. 1997. Letter to Committee on Space Shuttle Meteoroid/Debris Risk Management from Joseph Loftus, Jr., Assistant Director (Plans), NASA Johnson Space Center. SA-97–178. July 15, 1997.

Lord, L.W. 1996. Memorandum to the Committee on International Space Station Meteoroid/Debris Risk Management from U.S. Air Force Major General Lance Lord, April 3, 1996.

NASA. 1997. Conjunction Summary for STS-26 through STS-82. Letter DM3–97–7. Houston: NASA.

Reeves, W. 1997. Presentation to the Committee on Space Shuttle Meteoroid/Debris Risk Management, Houston, Texas, June 16, 1997.

USSPACECOM and JSC (United States Space Command and Johnson Space Center). 1996. Memorandum of Agreement for Space Control Operations Relationship, Space Shuttle Program Support, and International Space Station Program Support. April 10, 1996.

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