10:15 〜 10:30
[AOS14-06] Issues of Relying on Resupply Missions from Earth and the Benefit of Laundry Systems for Sustainable Space Exploration
キーワード：有人宇宙探査、物資補給ミッション、ウェルビーイング、洗濯システム、サステナビリティ
To sustain life aboard the International Space Station (ISS), essentials such as air, water, and food are periodically resupplied from Earth. However, this approach is highly inefficient. For example, delivering 21 tons of life-support supplies—which constitutes only 0.21% of the total launch mass—requires 699 tons of rocket dry mass, 9,311 tons of propellant, and 103 tons of cargo spacecraft. When you compare the recovered water mass onboard the ISS and the first stage engine mass of Falcon 9’s rocket (totaling 114 tons), it represents only 1.13% of the total mass, while the remaining 10,019 tons (98.87%) is discarded.
There are several drawbacks to relying on this resupply system:
1. Risk of Consumable Shortages
A failure in launch vehicles or cargo spacecraft can result in a shortage of critical consumables such as gas tanks, water bags, and food packages.
2. Waste Management Issues
Aside from air and water, items like food containers, experimental equipment, and other waste are discarded after use. Waste is stored temporarily aboard the ISS until it can be loaded onto a cargo supply spacecraft, which then burns up during atmospheric re-entry. This temporary storage occupies valuable space in each module, complicating stowage management and contributing to odor issues.
3. Complexity of Cargo Transfer Operations
Loading and unloading operations are complex, labor-intensive tasks that burden both the crew and ground control teams.
4. Impact on Astronaut Well-being
Astronauts prefer to have more variety in food. They also need to wear same garments, including underwear, for days or even weeks. With crew members exercising for two and a half hours daily, their workout clothes tend to develop odor. Studies suggest that the required clothing mass per crew member per day ranges from 0.206 to 1.690 kg/CM-d. The total clothing mass supplied from Earth between October 2017 and February 2020 was estimated at only 0.396 kg/CM-d. Although these numbers might imply sufficient supply, in reality, astronauts endure prolonged wear of the same items.
Developing an onboard laundry system could significantly improve this situation. By reusing clothes and towels for an entire year through such a system, we could potentially save approximately 761 kg of clothing and 913 kg of towels/wipes, translating to an annual cost saving of around $33.5 million. Of course, the benefits must be weighed against the costs and potential risks. Exploring alternatives to traditional water-based laundering—such as leveraging the unique aspects of the space environment (e.g., ultraviolet radiation and vacuum conditions)—could further enhance this solution. Beyond cost savings, a laundry system would greatly improve crew's Well-being by reducing the stress associated with reusing the same garments and mitigating odor issues.
There are several drawbacks to relying on this resupply system:
1. Risk of Consumable Shortages
A failure in launch vehicles or cargo spacecraft can result in a shortage of critical consumables such as gas tanks, water bags, and food packages.
2. Waste Management Issues
Aside from air and water, items like food containers, experimental equipment, and other waste are discarded after use. Waste is stored temporarily aboard the ISS until it can be loaded onto a cargo supply spacecraft, which then burns up during atmospheric re-entry. This temporary storage occupies valuable space in each module, complicating stowage management and contributing to odor issues.
3. Complexity of Cargo Transfer Operations
Loading and unloading operations are complex, labor-intensive tasks that burden both the crew and ground control teams.
4. Impact on Astronaut Well-being
Astronauts prefer to have more variety in food. They also need to wear same garments, including underwear, for days or even weeks. With crew members exercising for two and a half hours daily, their workout clothes tend to develop odor. Studies suggest that the required clothing mass per crew member per day ranges from 0.206 to 1.690 kg/CM-d. The total clothing mass supplied from Earth between October 2017 and February 2020 was estimated at only 0.396 kg/CM-d. Although these numbers might imply sufficient supply, in reality, astronauts endure prolonged wear of the same items.
Developing an onboard laundry system could significantly improve this situation. By reusing clothes and towels for an entire year through such a system, we could potentially save approximately 761 kg of clothing and 913 kg of towels/wipes, translating to an annual cost saving of around $33.5 million. Of course, the benefits must be weighed against the costs and potential risks. Exploring alternatives to traditional water-based laundering—such as leveraging the unique aspects of the space environment (e.g., ultraviolet radiation and vacuum conditions)—could further enhance this solution. Beyond cost savings, a laundry system would greatly improve crew's Well-being by reducing the stress associated with reusing the same garments and mitigating odor issues.