Two vacuum chambers were used in tandem to perform a launch depressurization test. The test article was mounted in a 10-ft (≈3 m) Vertical Vacuum Chamber (Chamber 248-10). The 25-ft (≈7.6-m) Space Simulator (Chamber 150-25) was rough-pumped and used for ullage.
Chamber 248-10 is 13 ft (≈4 m) in diameter by 37 ft (≈11.2 m) high; Chamber 150-25 is 27 ft (≈8.2 m) in diameter by 85 ft (≈26 m) high. A 21-in. (≈0.5-m) diameter vacuum line with a butterfly valve connects the two chambers. The inflatable space habitat would be mounted in Chamber 248-10. Chamber 150-25 would be pumped to approximately 44 Torr (≈5.9 kPa).
The launch depressurization profile was traced onto the paper of a strip chart recorder. A signal from a pressure transducer mounted on Chamber 248-10 was fed into the strip chart recorder. With the valve open to Chamber 150-25 and the building’s axial compressor, and eight Stokes pumps drawing vacuum on the vacuum line, the butterfly valve connecting Chamber 248-10 was manually opened. The operator of the butterfly valve adjusted the valve position so that the pressure transducer’s trace on the strip chart followed the trace of the depressurization profile.
This work was done by Patrick J. Martin and Paul L. Van Velzer of Caltech for NASA’s Jet Propulsion Laboratory. NPO-49615
This Brief includes a Technical Support Package (TSP).
Performing Launch Depressurization Test on Large Test Articles Using Two Vacuum Chambers in Tandem
(reference NPO49615) is currently available for download from the TSP library.
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Overview
The document is a technical support package from NASA detailing the procedures and challenges associated with performing launch depressurization tests on inflatable space habitats. It was presented at the 28th Space Simulation Conference in November 2014 and is associated with the Jet Propulsion Laboratory (JPL) at the California Institute of Technology.
The primary focus of the document is on the testing of inflatable habitats, which are considered for use in space missions, including potential deployment on the International Space Station (ISS). The tests aim to evaluate the structural integrity and performance of these habitats under conditions simulating launch depressurization.
Key aspects of the testing process include:
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Pre-Test Preparations: Eight dry runs were conducted to ensure readiness. Modifications were made to the test profile to expedite the transonic period, as directed by the project chief engineer.
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Test Execution: The testing involved multiple runs. The first test run encountered issues with the customer’s Data Acquisition System (DAS), leading to a request for a repeat. The second test run was successful, meeting all requirements, and the test article showed no signs of damage or expansion.
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Challenges Faced: The team faced several challenges, including a tight one-month window for testing, technical hurdles such as modifying setups to bypass interlocks and running chambers in tandem, and the need for adequate training for personnel involved in the tests. Additionally, there were contractual constraints that required 30 days to open the contract after confirming the feasibility of the tests.
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Technical Support and Collaboration: The document emphasizes the collaborative nature of the project, involving various teams and expertise from NASA and JPL. It also highlights the importance of thorough documentation and adherence to safety protocols during testing.
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Future Implications: The results of these tests are crucial for advancing the development of inflatable habitats, which could play a significant role in future space exploration missions. The insights gained from the testing process are expected to inform design improvements and operational strategies for inflatable structures in space.
Overall, the document serves as a comprehensive overview of the methodologies, challenges, and collaborative efforts involved in testing inflatable space habitats, underscoring NASA's commitment to innovation and safety in aerospace technology.
