Sierra Space, a leading, pureplay commercial space company building the first end-to-end business and technology platform in space, announced that the company’s LIFE™Habitat (Large Integrated Flexible Environment) successfully completed a third stress test – this time for duration – exceeding NASA certification requirements and demonstrating the inflatable structure’s integrity for sustaining human life in space for long periods of time.
This latest assessment, called an Accelerated Systematic Creep Test, is a destructive materials testing method by which test engineers load the test unit – a subscale version of the inflatable habitat – with a sustained amount of pressure over time until it fails. The unit’s “softgoods” pressure shell burst after over 150 hours, exceeding NASA’s short-term, recommended creep duration target of 100 hours. High-strength softgoods materials are sewn and woven fabrics – primarily Vectran – that become rigid structures when pressurized and can provide safe and sustainable architecture for space habitation.
This latest creep test is a different kind of stress test than the two previous ones conducted in July and November, which pressurized units with increasing loads until they burst at maximum or Ultimate Burst Pressure (UBP). All three tests took place within six months, further demonstrating Sierra Space as a market leader in the development of softgoods inflatable habitat technology, a key step in facilitating extended human missions to low-Earth orbit, the moon and Mars.
“LIFE Habitat represents the essential technology developments needed to one day enable humans to live and work in space,” said Sierra Space CEO Tom Vice. “Habitat units are a key element in Sierra Space’s platform in space, and this crucial milestone illustrates that our team has exceeded programmatic requirements that validate critical aspects of the LIFE Habitat design. These results will propel us in 2023 as we mature the technology via full-scale development and continue toward full NASA certification.”
Sierra Space, its partner ILC Dover and NASA subject matter experts performed the subscale Accelerated Systematic Creep Test in December 2022, at NASA’s Marshall Space Flight Center in Huntsville, Alabama. The purpose of the test was to determine the duration of time that LIFE Habitat’s pressure shell could last during its on-orbit operational mission life.
NASA designed a climate-controlled, disposable building in which the test was performed. This building was specifically built to meet two requirements: 1) to protect the test article (Sierra Space’s pressure shell) during the duration of the test and 2) to be expendable once the article successfully burst upon maximum creep pressure and duration. Due to the explosive nature of the test, the team placed the sub-scale space habitat adjacent to the flame trench of the Saturn 1/1B test stand, where NASA tested rockets for the Apollo program.
“Sierra Space’s LIFE Habitat pressure shell has an on-orbit performance requirement of 15 years, but with softgoods, there is a ‘times four’ safety requirement set by NASA, so we must ultimately prove we’re viable for 60 years,” said Shawn Buckley, LIFE Chief Engineer and Senior Director of Engineering at Sierra Space. “Based on data from this first subscale creep test, we well exceeded the on-orbit mission performance requirement of 60 years for inflatable structures within our current architecture.”