Original Date: 04/26/1999
Revision Date: 01/18/2007

Marshall Space Flight Center’s (MSFC’s) Plating Research Facility is currently developing a plating process which will allow multiple replicated optical mirrors to be produced from one mandrel. Once finalized, this process will be implemented in the Constellation X and Next Generation Space Telescope programs. The previous process involved multiple mandrels of the same shape and size on which the mirror material was plated and polished. The challenge for the Plating Research Facility is to develop the processing for space-based optical systems with much larger apertures and greater resolution, which does not require post-polishing.

The technical objective is to demonstrate a replicated optical systems manufacturing process that uses a single process flow: polish a single mandrel; apply electroless nickel-phosphorus; diamond turn and polish; apply gold coating; electroform nickel alloy shell; separate the shell; clean the mandrel; and repeat for next shell. Criteria for alloy selection include high specific strength, ultra-low durability, high elastic modulus, and the ability to maintain the optical figure without deformation. Technical problems encountered include the measurement of zero stress environment during plating, weight budget versus optical performance, and support structures needed to stabilize the shell.

MSFC’s developers have learned to define and control multiple plating parameters including temperature, current density, component placement in tanks, bath chemistry and consumption rate, shielding, and fluid flow. The process is expected to help industry manufacture more accurate space telescopes.

For more information see the Point of Contact for this survey.