Scope of project: Build 30 antenna array supports for the FORMOSAT-7 Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC-2) satellite mission. The mission comprises a 12 satellite constellation, each satellite with 2 antennas. Through this project, RedEye successfully entered NASA JPL’s Approved Supplier List.
Functional purpose of parts: The supports anchor antenna arrays that will capture atmospheric and ionospheric data to help improve weather prediction models and advance meteorological research on Earth.
Description of parts:
- Each support has 12 cone-like structures that were built together as one piece
- Highly-complex geometries with multiple features
- Tight dimensional tolerances (within 1 percent)
- Internal structures
- To build these parts with any other method, there would’ve been significantly more expense associated with assembly time and multiple components, measurements, etc.
Part dimension: Approximately 22.36” x 16.31” x 3.86”
Additive manufacturing technology used: Fused Deposition Modeling (FDM)
Material: ULTEM 9085
About ULTEM 9085: A high strength engineering-grade thermoplastic, which has excellent radio frequency and structural properties, high temperature and chemical resistance and is qualified for spaceflight. ULTEM is also flammability rated by the Federal Aviation Administration (FAA).
Support materials required for build: None. All shapes were designed with a maximum “overhead angle” of 45 degrees to avoid using break-away ULTEM support material during the build.
Strength and load requirements for parts: Parts have been qualified to operate in the environment consistent with an orbit 500-800 km above earth, including vacuum pressure and temperature ranges from approximately -100 through +100 degrees Celsius.
The flight hardware has also been tested and qualified for the acceleration, shock, thermal and vibration environments they will experience during rocket launch and the mission duration. The maximum predicted acoustic environment requirement for launch or Overall Sound Pressure Level (OASPL) is 139.6 dB.
Project timing: From March 2012 to June 2013, RedEye produced several antenna array structures for form, fit and function testing, and design reviews. Each array took approximately 58 hours to build. In November 2013, RedEye delivered 30 antenna array structures for final testing, Critical Design Review (CDR) and integration.
Throughout each design revision, RedEye’s project engineering team worked closely with JPL to process STL files to ensure the parts met exact tolerances and to minimize secondary operations.
Secondary operations performed: RedEye’s finishing department deburred the parts where needed, stamped each with an identification number and included a material test coupon. It also reamed holes for fasteners that attach to the aluminum honeycomb panel and the small channels throughout the cones to the precise conducting wire diameter.
Then, NASA applied a layer of S13G protective paint to the parts for further protection against oxygen atoms and ultraviolet radiation.
Tests conducted on the parts: In addition to standard functional testing (i.e. antenna beam pattern, efficiency, and impedance match), the parts were tested to meet NASA class B/B1 flight hardware requirements, including:
- Susceptibility to UV radiation
- Susceptibility to atomic oxygen
- Outgassing (CVCM index measured to be 0 percent)
- Thermal properties tests – in particular, compatibility with aluminum panels (aluminum has a slightly different coefficient of thermal expansion than non-glass-filled ULTEM 9085)
- Vibration / acoustic loads standard for launch
- Compatibility with S13G white paint and associated primer
Launch timing: The spacecraft bus configuration that carries the satellites is currently being assembled and tested. FORMOSAT-7/COSMIC-2 will launch six satellites into low-inclination orbits in May 2016, and another six satellites into high-inclination orbits in early 2018.
Filed Under: Aerospace + defense