Waste Management Options for Long-Duration Space Missions: When to Reject, Reuse, or Recycle

Abstract

The amount of waste generated on long-duration space missions away from Earth orbit creates the daunting challenge of how to manage the waste through reuse, rejection, or recycle. The option to merely dispose of the solid waste through an airlock to space was studied for both Earth-moon libration point missions and crewed Mars missions. Although the unique dynamic characteristics of an orbit around L2 might allow some discarded waste to intersect the lunar surface before re-impacting the spacecraft, the large amount of waste needed to be managed and potential hazards associated with volatiles recondensing on the spacecraft surfaces make this option problematic. A second option evaluated is to process the waste into useful gases to be either vented to space or used in various propulsion systems. These propellants could then be used to provide the yearly station-keeping needs at an L2 orbit, or if processed into oxygen and methane propellants, could be used to augment science exploration by enabling lunar mini landers to the far side of the moon.

Body size and its implications upon resource utilization during human space exploration missions

“…For instance, based on the volume of a single 1.53-MJ portion of thermostabilized 'ready-to-eat' food 20 , the additional food required for a 1,080-d mission would occupy a volume of 3.8-m 3 . Food and its packaging, in addition to human waste, are predicted to be greatest contributors to exploration mission waste 22,23 . Ewert and Broyan 22 estimated that, for a 1-year mission (1,460-human days), a crew of four would need approximately 2,250-kg of food within 400-kg of packaging, with human waste estimated at 400kg requiring a further 0.7-m 3 of storage.…”

Resource or waste? A perspective of plastics degradation in soil with a focus on end-of-life options

“…So, to avoid liquid droplets on the inside surface of the footballs, Heat Melt Compactor Technology (HMC) is used for trash handling. Trash that contains at least 20% plastic and 25% water (Linne et al., 2014). The HMC technology provides a 7:1 decrease in final volume via compression and heat yielding a dry, microbially stable, trash tile football containing more than one tenth of polyethylene, which, during heating caramelizes organic residuals as well, becoming softer, getting a dimensionally firm tile in the compressed state during cooling; these tiles will function as a last disposal object or as a storage form until repurposing/processing into convenient further items (Broyan et al., 2014).…”

Formulation of a Simulated Wastewater Influent Composition for Use in the Research of Technologies for Managing Wastewaters Generated during Manned Long-Term Space Exploration and Other Similar Situations—Literature-Based Composition Development

“…It is estimated to cost USD 10,000 to send one pound of water to the low Earth orbit, which would increase the cost by up to 40 times to send the same payload to Mars [ 2 ]. A waste model for crewed missions on a one-way Mars transit, based on the International Space Station (ISS) waste production, shows that 30% was human waste (feces and urine) and 24% was food and packaging by weight [ 3 ]. The waste in current human-inhabited space systems, such as the ISS, is collected and returned to Earth on a return payload forced into the Earth’s atmosphere, and is thus incinerated when entering the Earth’s atmosphere via entry-induced heating.…”