NASA performed an analysis of supplies sent to the ISS between October 2017 to February 2020. The objective of the analysis was to determine the composition of consumable logistics mass used in space exploration. Payload items, and infrequently supplied items not critical to maintain life were excluded from the analysis. The analysis reviewed detailed manifests and applied a taxonomy to categorize items consistently.
Top Contributors
The top contributors to consumable logistics mass are identified in the following chart.
The following sections breakdown the relative contribution to mass of consumable logistics items by subcategories. Note that subcategory items contributing less than 1% are not included on the charts, but are included in the spreadsheet at the end of this article.
Science and Outfitting
The Science and Outfitting category does not have a subcategory breakdown as it contains one hundred eleven items used in outfitting or experimentation with little commonality aside from their use. This category’s largest contributors to mass are: lithium-ion battery replacement units; and in-flight maintenance and structural components. Examples of smaller items include double cold insulated sample bags, and incubation bags.
Environmental Control and Life Support Systems
The largest portion of Environmental Control and Life Support Systems (ECLSS) is the Life Support System subcategory which contains only Russian supplied items manifested as Life Support Systems (LSS). Information on the exact breakdown of LSS items was not provided by the analysis. The next largest portion is the Water System which contains water containers, the water supply system, resupply water tanks and improved water resupply tanks, water sample collection packets and all other water-based consumables. Next, the Monitoring and Control subcategory contains items used to maintain a steady station environment such as air revitalization and atmospheric monitoring, the thermal control system, the power supply subsystem, acoustic monitors, and coliform detection packets. The Kits subcategory contains: Aelita kits (Russian cleanliness supplies), Ekosfera kits (biological testing), and NORS (Nitrous/Oxygen Recharge System) maintenance kits. Waste Containment contains water waste bags and solid waste containers. Toilet Hardware includes toilet replacement hardware as well as urine receptacles.
Food
Food is broken down into three subcategories. The largest is Packaged Food. This subcategory contains: Bulk Overwrap Bags (BOBs) that are the most common form of American food distribution; food rations containers which contain Russian food; Cargo Transfer Bags (CTBs) labeled as containing food; and fresh produce selections. The Systems subcategory contains the food supply system which is another Russian food source. Kits includes nutritional supplement kits, small food kits, and chewing gum kits.
Hygiene
The Hygiene category contains items used to maintain personal cleanliness. Its largest subcategory is Towels/Wipes which contains various forms of towels, washcloths, wipes and napkins both wet and dry. The Other Items subcategory contains items that were miscellaneous and did not easily fit within other subcategories such as sleeping bag liners, nail clippers, hair combs, tweezers, and generalized hygiene kits. The Cargo category contains all CTBs designated for hygiene use. Solutions and Creams contains lotion, body bath, makeup, and hand cream. The Dental subcategory contains toothpaste, floss and toothbrushes.
Operational Supplies
Operational Supplies contains the most subcategories. Starting from the most significant, the Bags subcategory contains plastic bags, mesh laundry bags, freezer bags, containment bags, and trash bags. The next largest category is Office Supplies which contains note pads, sticky notes, printer paper, scissors, and binder clips. The Flight subcategory contains materials used for flight such as flight kits, copies of flight procedures, kneeboards and post flight analysis packets. Next, the Laptops subcategory contains all laptop computers and their components such as hard drives, power cables, batteries and adapters. The Multi-Tools subcategory includes the handheld multi-tools used by the crew.
Clothing
Clothing consists of all items worn by the crew inside of the vehicle. The largest subcategory is Shirts, which includes exercise shirts, T-shirts, crew preference shirts, and sleepwear tops. Undergarments contains all underwear worn by the crew. Specialized/Other includes coveralls, training/loading suits, fire protection equipment, and penguin suits which have a series of elastic bands and are used to compress the body to simulate gravity and counteract the physical effects of spending time in space. The Socks subcategory contains all socks worn by the crew including ankle socks, exercise socks, and crew preference socks. Generalized contains bags such as CTBs designated to hold clothing.
EVA Consumables
Any clothing and other materials used outside of the spacecraft are included in the EVA Consumables category. Wearables, the largest subcategory, includes replacement space suit parts such as gloves, maximum absorption garments (also known as adult diapers), liquid cooling vests and thermal comfort garments. The Outfitting subcategory includes the EV crew options kit, attachments, and moisture barriers. Supplies covers various types of tapes, EVA wire ties, stericide wipes, and absorbent paper. The Covers subcategory contains protective covers for arm disconnects, rings, and battery cartridges. The Other subcategory includes crew identifiers, suit patches, foam sheets, and Valsalva devices which allow astronauts to equalize the pressure in their ears without using their hands to block their nose.
Healthcare Consumables
The Healthcare Consumables category contains items used to maintain health, treat or diagnose crew members. The largest subcategory, Fitness, contains parts for the treadmills and cycle ergometers. The Medical Kits subcategory contains the ISS Medical Accessory Kit, urisys sets, and other generalized medical kits. The Monitoring subcategory includes items manifested as medical monitoring equipment. Exposure contains dosimeters and harmful exposure protection equipment. The Small Items subcategory contains sterile gauze, batteries specifically designated for medical equipment, cotton swabs, and emesis bags (also known as vomit bags). Cardio contains the cardiomed system and cardiocassettes.
Personal and Recreational
The Personal and Recreational category is the smallest category and contains items used by the crew for leisure or entertainment. The Music subcategory contains mp3 players and the cables that come with them. Personal contains comfort cases and items manifested as personal items both of which which consist of small crew picked items like books, CDs, small instruments, or foods. The Headphones subcategory contains various headphones associated with music players.
Discussion
The results can be used to identify potential areas of improvement and highlight the rates at which significant items are supplied. Moreover, the results can be used support analysis of alternative logistics supply options such as: utilizing in space manufacturing for supplies vs. manifesting spares, or cleaning clothing in flight vs. discarding it.
Source Data
Source data is provided below.
Additional information for the curious
For detailed information on space logistics vehicles servicing space stations, see these articles: Cargo Spacecraft from the Past to the Future, Insights into Space Station Logistics Spacecraft – Past, Present, and Future, and The World’s Cargo Spacecraft.
For the original NASA analysis, see this article: Analysis of Historical International Space Station Logistical Mass Delivery.