396. Mapping Life Support System Functions and Technologies to Commercial Spaceflight Applications

Team

Research Area

3.0 Human Spaceflight

Project Description

A human spacecraft requires an Environmental Control and Life Support System (ECLSS) to meet the physiological needs of the occupants. This includes cabin pressure maintenance, atmosphere revitalization and thermal control, as well as provision of potable water and food, and subsequent collection of waste. Each of these required functions can be met by a number of different technologies. In some cases, a given technology, a lithium hydroxide (LiOH)-based CO2 scrubber, for example, is typically intended to provide a single primary function (CO2 removal), but also results in water absorption through a hydration reaction that must be accounted for in a mass balanced system. Additionally, application of the LiOH system requires directed airflow and circulation within the cabin, which drives the need for supporting infrastructure to move the air through appropriate ducting to concentrate the airstream into the LiOH. A wide variety of other components can also meet the function of CO2 removal, each with their own set of performance capabilities and supporting needs. In other cases, a single technology is intended to perform multiple functions, such as a condensing heat exchanger that both removes the cabin thermal load and dehumidifies the air. Similarly, the other ECLSS functions can be met by any number of technologies integrated in various combinations. Therefore, in order to ensure that the life support system requirements are met by the vehicle, each function must be mapped to a specific ECLSS technology and the supporting needs of each technology must be met by the integrated system.
Beyond this baseline of ensuring the fundamental objectives of ECLSS are achieved, the result of which can largely be characterized by component power, mass and volume, further identification and additional analysis of more detailed operational parameters can be used to refine the system in terms of safety and operability. This is accomplished by considering factors such as reliability, failure modes and effects, mean time between failure, maintainability, user interfaces, etc. This process extends the baseline functional needs toward a more optimized, robust ECLSS design, including related operational aspects typically defined as a Crew Accommodations subsystem. Collectively, this information can be used to define a compliance matrix for requirements and can further serve as a guide for designers to help ensure an optimal, habitable environment is provided and the overall needs of the occupants are met.

Project Outcomes

This task is expected to produce two primary outcomes. First, from AIM 1, functional requirements for ECLSS will be defined and characterized with representative model systems established. Feedback will be also provided to the FAA AST office regarding suggested edits and/or additions to the ECLSS guidelines document noted above. Additionally, per AIM 2, a foundation will be laid for future ECLSS trade off studies by providing a detailed set of operational parameters needed to evaluate the use and integration of each technology option identified. In both cases, input from industry and government will also be solicited for consideration in the final products, which will be summarized in a comprehensive, detailed final report, presented at the COE CST ATM9 and ATM10 meetings, and submitted for publication, as applicable. This work builds on prior COE CST tasks addressing human-rating, risk analysis and occupant safety.
AIM 1: ‘Generic ECLSS Model’ – a map of ECLSS functions will be defined and coupled with existing technologies capable of meeting the needs as representative systems for different flight profiles ranging from suborbital to orbital short duration and orbital long duration. (Tasks 1-4)
AIM 2: ‘ECLSS Tradeoff Models’ – a foundational database will be established to identify a comprehensive listing of current and future ECLSS components and related technologies with detailed performance specifications needed to enable future trade off model analysis.

Summary of Output

The task is intended to augment and build upon the FAA’s Environmental Control and Life Support Systems for Flight Crew and Space Flight Participants in Suborbital Space Flight document (Version 1.0, April 2010). The outcome will support the current research roadmap milestones titled ‘Generic ECLSS Model’ (near-term 0-3 years) and ‘ECLSS Tradeoff Models’ (mid-term 3-10 years) in Research Theme 3 Human Ops and Spaceflight by providing a foundation for the generic model based on required functionality and a database of current and future ECLSS technologies for the tradeoff model.
Additionally, in support of these objectives, we will solicit industry participation in the process to ensure consensus to the extent possible is achieved in the outcomes, as well as maintain interactions with NASA and the FAA as warranted. This collective insight offers a multidisciplinary vantage point from which to ensure a comprehensive perspective is maintained.