Engineering topics

Litty, E. C.

Publications and source records attributed to Litty, E. C..

4 records

NASA NTRS2001

Enabling technology for NASA's Europa Orbiter mission

The authors will describe the drivers for the subsystem requirements in the Europa Orbiter mission, in particular the mission criticality of the IMU and the predicted natural space radiation environments that require enabling technologies to be identified. Descriptions of the Europa IMU and the HRG technology are given with emphasis on the inherent radiation hardness in the HRG principle of operation and sensor construction, as well as the steps taken to further harden the sensor electronics.

inertial measurement unit inertial reference unit ↗

NASA NTRS1996

An IRU for Cassini

The JPL Inertial Reference Unit (IRU) is the single most sophisticated assembly on the Cassini Spacecraft. At the core of the IRU is the state-of-the-art, Litton (formerly Delco) Hemispherical Resonator Gyroscope (HRG). Launched in October 1997, Cassini's trajectory utilizes gravity assist manuevers around Venus (twice), Earth, and Jupiter over a seven year period, arriving at Saturn in June 2004.

Cassini IRU Inertial Reference Unit attitude stabi↗

NASA NTRS1981

A Voyager attitude control perspective on fault tolerant systems

In current spacecraft design, a trend can be observed to achieve greater fault tolerance through the application of on-board software dedicated to detecting and isolating failures. Whether fault tolerance through software can meet the desired objectives depends on very careful consideration and control of the system in which the software is imbedded. The considered investigation has the objective to provide some of the insight needed for the required analysis of the system. A description is given of the techniques which have been developed in this connection during the development of the Voyager spacecraft. The Voyager Galileo Attitude and Articulation Control Subsystem (AACS) fault tolerant design is discussed to emphasize basic lessons learned from this experience. The central driver of hardware redundancy implementation on Voyager was known as the 'single point failure criterion'.

Rasmussen, R. D.↗

NASA NTRS1980

Attitude control fault protection - The Voyager experience

The length of the Voyager mission and the communication delay caused by the distances involved made fault protection a necessary part of the Voyager Attitude and Articulation Control Subsystem (AACS) design. An overview of the Voyager attitude control fault protection is given and flight experiences relating to fault protection are provided.

Litty, E. C.↗