Michael S. Woronowicz

NASA NTRS2022

Further Development of a Function Generator Technique

Further features and properties of functions generated by generalization of the process originally uncovered to describe the evolution of pressure in a rigid volume due to outgassing or desorption are explored. Properties presented include development of a general Maclaurin series associated with these functions, a limitation in using integration by parts to produce asymptotic expansions, and a general description of an implicit Adams-Moulton method for numerical quadrature of transformed functions. These developments are then applied to develop and explore functions that solve the Sievert integral and the modified Bessel function of the first kind, order zero. Features of the error function and the incomplete lower gamma function are also considered.

Michael S. Woronowicz↗

NASA NTRSDate not supplied

Obtaining cryogenic molecular transport data for analysis

The James Webb Space Telescope (JWST) has a primary mirror, made of 18 segments, and a secondary mirror (SM) that are used to direct the light of desired targets. While on orbit, the secondary mirror assembly (SMA) was stowed for approximately 10 days and was subject to molecular contamination outgassing from the cavity of the secondary mirror support structure (SMSS) in-board hinge (IBH) which contains cables, motors, resolvers, and coatings. The main concern during this period before SMA deployment is the accumulation of ice due to the lack of a heater on the SMA. The temperature differentials between the IBH surfaces and SMA could cause redistribution of contaminants. To address this concern, single layer insulation (SLI) was used to create adequate venting and path redirection of outgassing from the IBH. Two separate thermal vacuum tests were performed to quantify this contamination: one Z307 ASTM E 1559 materials test of the radiator paint used on the motor of the IBH and a separate test on a primary mirror backplane assembly (PMBA) qualification engineering test unit (ETU) of the IBH. These tests approximately followed the predicted SMA pre-deployment thermal environment. To quantify source rates in case of a leak, the motor and resolver sides were separated and quartz crystal microbalances (QCM) were used to measure the deposition of water. The SLI redesign and implementation and outgassing measurements to understand leak effects from the IBH were essential to mitigate the deposition of contamination on the SMA.

James Webb Space Telescope, contamination, cleanro↗