Greater dispersion at entry on AS-501 with the new IMU

FA/Assistant ChiefJUL 27 196767-FM-T-50FM/Deputy ChiefGreater dispersion at entry on AS-501 with the new IMU

You have expressed concern about the somewhat poorer performance of the new platform in Spacecraft 017. While at MIT last week Dan Lickly and I spoke to John Miller about this. John says the component which con- tributes the most to dispersion in flight path angle at the entry interface is the Y gyro, as you know. The dispersion on this replace- ment gyro is almost exactly double that of the old one [3.0 MERU in place of 1.6 MERU, whatever that is]. According to a curve he had — this alone will result in 0.6° flight path angle dispersion at entry (3σ) assuming a perfect nav. update prior to the second SPS maneuver.