Engineering topics

Lui, Yan

Publications and source records attributed to Lui, Yan.

3 records

NASA NTRS2016

James Webb Space Telescope (JWST) Integrated Science Instruments Module (ISIM) Cryo-Vacuum (CV) Test Campaign Summary

JWST Integrated Science Instruments Module (ISIM) completed its system-level space simulation testing program at the NASA Goddard Space Flight Center (GSFC). In March 2016, ISIM was successfully delivered to the next level of integration with the Optical Telescope Element (OTE), to form OTIS (OTE + ISIM), after concluding a series of three cryo-vacuum (CV) tests. During these tests, the complexity of the mission has generated challenging requirements that demand highly reliable system performance and capabilities from the Space Environment Simulator (SES) vacuum chamber. The first test served as a risk reduction test; the second test provided the initial verification of the fully-integrated flight instruments; and the third test verified the system in its final flight configuration following mechanical environmental tests (vibration and acoustics). From one test to the next, shortcomings of the facility were uncovered and associated improvements in operational capabilities and reliability of the facility were required to enable the project to verify system-level requirements. This paper: (1) provides an overview of the integrated mechanical and thermal facility systems required to achieve the objectives of JWST ISIM testing, (2) compares the overall facility performance and instrumentation results from the three ISIM CV tests, and (3) summarizes lessons learned from the ISIM testing campaign.

Yew, Calinda↗

NASA NTRS2016

James Webb Space Telescope (JWST) Integrated Science Instruments Module (ISIM) Cryo-Vacuum (CV) Test Campaign Summary

JWST Integrated Science Instruments Module (ISIM) has completed its system-level testing program at the NASA Goddard Space Flight Center (GSFC). In March 2016, ISIM was successfully delivered for integration with the Optical Telescope Element (OTE) after the successful verification of the system through a series of three cryo-vacuum (CV) tests. The first test served as a risk reduction test; the second test provided the initial verification of the fully-integrated flight instruments; and the third test verified the system in its final flight configuration. The complexity of the mission has generated challenging requirements that demand highly reliable system performance and capabilities from the Space Environment Simulator (SES) vacuum chamber. As JWST progressed through its CV testing campaign, deficiencies in the test configuration and support equipment were uncovered from one test to the next. Subsequent upgrades and modifications were implemented to improve the facility support capabilities required to achieve test requirements. This paper: (1) provides an overview of the integrated mechanical and thermal facility systems required to achieve the objectives of JWST ISIM testing, (2) compares the overall facility performance and instrumentation results from the three ISIM CV tests, and (3) summarizes lessons learned from the ISIM testing campaign.

Yew, Calinda↗

NASA NTRS2007

Pan and Tilt Platform for a Thermal Vacuum Video Camera

The purpose of the Space Simulation Test Engineering (SSTE) Section at NASA Goddard Space Flight Center is "to provide full service test support, engineering expertise, and state-of-the-art facilities to perform simulated space and thermal cycle testing of Earth orbit and deep space flight hardware"(ref. 1). During the Integration & Testing phase of space flight projects, flight hardware must successfully demonstrate its functionality under conditions similar to the actual environment experienced in space. When testing hardware with mechanical components, such as antenna extensions, door openings, or solar panel deployments, visual observation would allow test personnel to verify mechanical operations in real-time. A video camera can supply data that the usual sensors inside a TV chamber cannot provide. Since mechanical functional testing could affect multiple regions of a test item, a camera with a fixed position may not be able to monitor and record the performance of different components of a mechanism, especially for large test items. By mounting the camera to a Pan and Tilt Platform, the camera can cover a larger area and its field-of-view (FOV) will increase significantly. This paper details the design process for the Pan and Tilt Platform.

Lui, Yan↗