Search NASA⌕ Search

Engineering topics

Webster, Julie L.

Publications and source records attributed to Webster, Julie L..

4 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2005

The Cassini Spacecraft Design and Operations

Designed and funded in the pre-'better, faster, cheaper' era, Cassini was built to be the one mission to Saturn for many years to come. Its complement of twelve Orbiter science instruments and the Huygens Probe make Cassini one of the most complex missions ever flown. With a seven-year cruise and Saturn Orbit Insertion now over, Cassini is settling in to perform a very ambitious prime mission over the next four years. This paper provides an overview of the spacecraft design and the mission operations to date.

mission operations↗
NASA NTRS2004

Managing Risk to Ensure a Successful Cassini/Huygens Saturn Orbit Insertion (SOI)

I. Design: a) S/C designed to be largely single fault tolerant; b) Operate in flight demonstrated envelope, with margin; and c) Strict compliance with requirements & flight rules. II. Test: a) Baseline, fault & stress testing using flight system testbeds (H/W & S/W); b) In-flight checkout & demos to remove first time events. III. Failure Analysis: a) Critical event driven fault tree analysis; b) Risk mitigation & development of contingencies. IV) Residual Risks: a) Accepted pre-launch waivers to Single Point Failures; b) Unavoidable risks (e.g. natural disaster). V) Mission Assurance: a) Strict process for characterization of variances (ISAs, PFRs & Waivers; b) Full time Mission Assurance Manager reports to Program Manager: 1) Independent assessment of compliance with institutional standards; 2) Oversight & risk assessment of ISAs, PFRs & Waivers etc.; and 3) Risk Management Process facilitator.

risk managment↗