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M2 Substrate Relocation

LSST E-News : 

The LSST secondary mirror (M2) substrate has been safely relocated from Harvard University in Cambridge, MA to the Exelis facility in Rochester, NY. The mirror’s trek, which involved the use of a 50-ton internal bridge crane to load the mirror transport box onto a wide-load flatbed truck and a 70-ton external crane to offload it at destination, covered 604 miles in a little over a day. The truck and pilot vehicle departed Harvard at 1 pm on October 20 and arrived in Rochester at 3 pm on October 21. Subsequently, Exelis personnel have disassembled the transport box and thoroughly inspected the substrate.

LSST Head of Safety Chuck Gessner observed the loading of the M2 transport box from Harvard Physics Lab storage onto the truck. LSST Telescope and Site Subsystem Manager Bill Gressler observed the mirror’s offloading at Exelis’ receiving area. Accelerometers were used to monitor and record acceleration, temperature, and movement forces on the mirror during its road trip. Neither the active nor the passive accelerometers indicated any problems during transport.

Delivery of the M2 substrate to Exelis highlighted the kick-off of the M2 Cell Assembly Fabrication effort. Exelis has been awarded the contract to process the M2 substrate to a finished polished state and also to provide final design, fabrication, assembly, test, and delivery of the M2 Cell Assembly. The M2 assembly will ultimately be integrated onto the telescope on Cerro Pachón in Chile. The 3.4-meter diameter mirror is a solid meniscus design fabricated from ultra low expansion (ULE™) glass manufactured by Corning Incorporated, Corning, NY.

View a gallery of images of the M2 relocation. 

LSST Telescope and Site Project Manager William Gressler and Exelis personnel pose with the LSST secondary mirror (M2) substrate in the vendor's receiving area.
Image Credit: 

LSST E-News Team


Suzanne Jacoby (Editor-in-Chief)
Robert McKercher (Staff Writer)
Mark Newhouse (Design & Production: Web)

Emily Acosta (Design & Production: PDF/Print)
Additional contributors as noted


LSST E-News is a free email publication of the Large Synoptic Survey Telescope Project. It is for informational purposes only, and the information is subject to change without notice. 
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Financial support for Rubin Observatory comes from the National Science Foundation (NSF) through Cooperative Agreement No. 1258333, the Department of Energy (DOE) Office of Science under Contract No. DE-AC02-76SF00515, and private funding raised by the LSST Corporation. The NSF-funded Rubin Observatory Project Office for construction was established as an operating center under management of the Association of Universities for Research in Astronomy (AURA).  The DOE-funded effort to build the Rubin Observatory LSST Camera (LSSTCam) is managed by the SLAC National Accelerator Laboratory (SLAC).
The National Science Foundation (NSF) is an independent federal agency created by Congress in 1950 to promote the progress of science. NSF supports basic research and people to create knowledge that transforms the future.
NSF and DOE will continue to support Rubin Observatory in its Operations phase. They will also provide support for scientific research with LSST data.   

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