One of the challenges of long duration space exploration is waste management. As waste streams are generated, unwanted trash items begin to accumulate in the cabin. During long duration missions, this aggregates into several tons of trash being stored inside the habitat, which makes orbital maneuvers more expensive and reduces the amount of habitable volume for the crew. NASA is taking a multi-pronged approach to waste management on long-duration spacecraft (see Waste to Base Materials Challenge: Sustainable Reprocessing Space and NASA Waste Jettison Mechanism Challenge). Three primary approaches are currently being investigated to help solve the problem with space trash:
- Thermally degrade the waste via a process called Trash-to-Gas. This approach gasifies the waste items, producing water and syngas which can be reutilized onboard or vented overboard for mass and volume reduction.
- Dry, stabilize, and compact the trash items. This approach removes the water from the trash, reduces trash volume, and produces trash tiles that may be effective for radiation protection. However, another method of removing the trash mass from the spacecraft is still required in conjunction with this approach.
- Jettison the trash via an airlock. This approach removes all of the trash mass and volume from the habitat but may not recover any of the resources within the discarded trash items.
This challenge will help support the development of the first approach, Trash-to-Gas. Trash-to-gas reactors are considered a sustainable approach to both near- and long-term waste management during long-duration space missions. The primary goal of this challenge is to create actionable design concepts for ash removal from a trash-to-gas reactor in microgravity.
A trash-to-gas reactor uses thermal degradation processes to gasify waste into a product that can be vented or repurposed as raw material for other spacecraft processes. Figure 1 depicts a high-level Trash-to-Gas process that will be utilized on future long-duration missions. Several products can be recovered from the trash reactor, including gas, water and solids. One of the solid by-products will be ash. This ash must be removed regularly, just like ash needs to be removed from a fireplace or grill. The ash removal step has not yet been designed for a space trash reactor. In Figure 1, the two dotted lines express the potential to either remove the ash by-products directly from the reactor or immediately after the reactor but before the ‘Post-Processing & Recovery” stage. Modifications to the existing reactor design are sought that will allow ash to be regularly and safely removed in microgravity conditions.
Awards:- This challenge has a total prize purse of $30,000 and will recognize the top three design concepts with first, second, and third prizes of $15,000, $10,000, and $5000 respectively.
Deadline:- 13-05-2022
