NextSTEP Hybrid Life Support System (HLSS)

NextSTEP Phase I Hybrid Life Support Systems (HLSS) effort assessed options, performance, and reliability for various mission scenarios using contractor-developed analysis tools and databases. A large scale Astro Garden^TM plant growth prototype was also fabricated. The prototype was scaled to accommodate a NASA Exploration Life Support Salad Crop Diet for a crew of four.

NextSTEP Phase II baseline efforts encompass two tasks that will result in a high fidelity Astro Garden-based HLSS testbed scaled to commercial habitat modules. The first task will include testing and refinement of the Astro Garden subsystems, and the Phase I Astro Garden prototype will be upgraded to a high-fidelity testbed to allow testing of HLSS technologies at a habitat scale. The second task will include refinement of the Life Support Multidimensional Assessment Criteria (LSMAC) alternative evaluation factors as the salad production architecture is further developed and HLSS life support technologies are further characterized. The Astro Garden plant growth system will also undergo further assessment for its ability to provide radiation shielding by using NASA's modeling software, which will allow different materials and hardware configurations to be assessed. 

Additional Phase II work includes Parabolic Flight Testing used to develop media-free water and nutrient delivery and recovery technologies that are logistically feasible for large-scale plant growth systems in space. Parabolic flights were conducted in March and November 2018. A technology demonstration aboard the International Space Station (ISS) is also planned to test nutrient delivery and recovery techniques. An eXposed Root On-Orbit Test System (XROOTS) will be developed and implemented for the ISS tech demo to evaluate the plant growth progression in a microgravity environment from seed to germination, to developmental roots, to a mature root system. XROOTS, used in conjunction with an onboard Veggie unit, will integrate alternative technologies and methods to supply and recover nutrient solution during the entire spectrum of the plant's growth development cycle.