More than One Way to Skin a Patent Under DOE: Vitiation in Lieu of Estoppel

In a spring 2001 decision, the U.S. Court of Appeals for the Federal Circuit affirmed a summary judgment of no doctrine of equivalents infringement of a Lockheed Martin satellite control patent by Space Systems/Loral (SSL), in view of an amendment based estoppel. Lockheed Martin Corp. v. Space Systems/Loral, Inc. In that 2001 decision, the Federal Circuit applied the Festo absolute bar rule. The U.S. Supreme Court, which had already granted certiorari in Festo, granted certiorari in Lockheed-Martin as well. After reversing Festo, the Supreme Court sent the Lockheed Martin case back to the Federal Circuit "for further consideration in light of" the Supreme Court’s Festo decision. Now, on remand, the same three-judge Federal Circuit panel has again affirmed the district court summary judgment of no doctrine of equivalents infringement, but this time based on an issue not addressed in the earlier decision: the "all elements" or "all limitations" rule. Lockheed Martin Corp. v. Space Systems/Loral, Inc., Case No. 00-1310 (Fed. Cir. Mar. 24, 2003).

The Federal Circuit noted that the remand by the Supreme Court did not necessarily require it to revisit the Festo estoppel issue. Rather, in the panel’s view the case on remand stands in the same posture as at the time it first reached the Supreme Court. In its new decision, the panel chose not to resolve the estoppel issue but, instead, to decide the appeal on another ground: the "all elements" or "all limitations" rule.

The patented system compensates for angular drift of geosynchronous satellites by manipulation of speed and angular momentum of a momentum wheel, having an axis parallel to the yaw axis of the satellite (pointing toward the center of the earth), so as to tilt the satellite and keep it continuously pointed at a target on the earth’s surface. The claimed system included an element specified as a "means for rotating said wheel in accordance with a predetermined rate schedule, which varies sinusoidally over the orbit at the orbital frequency of the satellite." The new panel decision focused on two functional limitations on this "means" element, the predetermined rate schedule and the sinusoidal variation.

The lower court interpreted the sinusoidal variation limitation to mean that the speed variation passes through zero and changes direction or sign. The parties apparently did not dispute this interpretation. While the wheel in the SSL satellite varies its speed, it does so with respect to a bias speed and, consequently, does not pass through zero, i.e., does not change direction or sign.

Also, the Federal Circuit adopted the lower court interpretation of the "predetermined" limitation requiring that the sinusoidal control function "does not include any unfixed real-time inputs," such as those from an earth sensor. The rate schedule used in the SSL satellite control responds to an actual real-time error sensed by an earth sensor. Over arguments by Lockheed regarding the open-ended nature of the claim, the Federal Circuit concluded that the accused satellite control did not utilize a "predetermined" rate schedule.

Finally, despite expert testimony as to the overall equivalence between the recited function as construed by the Federal Circuit and the function performed by SSL satellite, the court concluded that there was no element that performs the properly construed function, and, therefore, that the claimed "means" element was entirely missing from the SSL satellite. The Federal Circuit held that a finding of infringement by equivalents, in the absence of operations that literally satisfies the two functional requirements, would "entirely vitiate the limitations" of the "means for rotating" claim element.