398 the performance of the architecture to instrument management, had as much "political" value as technical  value.  Whereas heritage arguments hurt the SSM development, the ESDM benefitted strongly from heritage. It required little more than cosmetic changes from the heritage LRO design; its development proceeded comparatively painlessly compared to the SSM, yet some lessons were learned, and classic lessons reinforced. The relative simplicity of the mechanism allowed for adequate analysis to be undertaken, and many developmental performance tests to be done. The vendor-supplied components, such as bearings, potentiometers, and dampers, were known early and hence procured early, with adequate time for chracterization testing and bake out. A dedicated breadboard was (correctly) not needed, as the TIRS flight design was a derated version of the original LRO design. This was the classic, proper heritage application case; the new mechanism was as close to "build-to-print" identical to the heritage mechanism as was reasonably possible.  The CCLL was just the opposite of the ESDM; There were no heritage mechanisms that would meet its  requirements. The 6-month development schedule, and a fixed set of available interfaces, drove the team to a non-traditional approach that was difficult to analyze, but relatively easy to test. Here the early breadboard was absolutely essential to verify function, measure forces, and test critical sliding clearances. Methods were developed to lot-qualify commercial grade mechanical hardware (with little or dubious traceability paperwork) for flight use (albeit at higher risk), as flight-quality components were impossible to procure in the available time.  The TIRS mechanisms development was undertaken knowing that a higher level of risk had to be  assumed in order to minimize the development time. Many weeks were lost and the instrument schedule re-arranged several times to accomodate delayed mechanism deliveries due to the consequences of this decision. Ultimately, the difficulties were overcome, the mechanisms were integrated into the instrument, and have functioned flawlessly throughout instrument environmental testing.  Acknowledgements  The authors would like to sincerely thank the many individuals whom, through their Herculean efforts during this rapid development, were key to the success of the TIRS mechanisms. They are: Melissa Edgerton, Alissa Mitchell, and Monica Zuray, Mechanisms Engineers. Edwin Lee, Randy Frazier, and Scott Weedon, Mechanical Designers. David Maidt, Thermal Analyst. Scott Hoeksema and Milagros Silverio, Contract Oversight. Tommy Emmett, Co-op Student. Andy Wohl, Mechanisms Integration &Test, Gordon Bowers, Technician. We would also like to especially thank Dr. Michael Dube, and Anh Tran for their assistance in bearing lubrication and analysis, and John Sudey for his expertise in jitter control.  References  1. Dennis Reuter, Cathy Richardson, James Irons, Rick Allen, Martha Anderson, Jason Budinoff,  Gordon Casto, Craig Coltharp, Paul Finneran, Betsy Forsbacka, Taylor Hale, Tom Jennings, Murzy Jhabvala, Allen Lunsford, Greg Magnuson, Rick Mills, Tony Morse, Veronica Otero, Scott Rohrbach, Ramsey Smith, Terry Sullivan, Zelalem Tesfaye, Kurtis Thome, Glenn Unger, Paul Whitehouse  "The Thermal Infrared Sensor on the Landsat Data Continuity Mission.” Geoscience and Remote Sensing Symposium (IGARSS) 2010 IEEE International, Honolulu, Hawaii   2. Budinoff, Jason G., R. Barclay, K. Bergandy, A. Matuszeski, J. Schepis,  "Development of The  Scene Select Mechanism for the Thermal Infrared Sensor Instrument.” Proc. 14th European Space Mechanisms & Tribology Symposium – ESMATS 2011, Constance, Germany (ESA SP-698, September 2011)  3. Capon, Thomas, “Design of a Digital Control System for Positioning a Scene Select Mechanism  Professional Intern Program Level II Project” NASA GSFC Code 544, July 2011