Introduction

For human exploration missions, it is critical to 

provide items such as food, water, air, spare 

parts, and other similar products required to 

sustain life, maintain systems, and allow for 

productive science and utilization activities. 

Together, these types of goods are referred to 

as logistics items. This white paper breaks down 

the different types of logistics items, explains the 

mission and architecture drivers that determine 

logistics item needs, and identifies the types of 

logistics items that tend to dominate overall 

needs. 

NASA has established a consistent process for 

developing initial estimates of logistics item 

needs for conceptual exploration missions. This 

process, which is based on previous spaceflight 

experience and input from technical experts, 

provides a comprehensive assessment of the 

logistics items needed to support exploration 

missions. Using a consistent process to 

estimate logistics item needs allows for proper 

assessment of logistics systems and consistent 

analysis of mission and architecture concepts. 

The process for estimating logistics item needs 

for conceptual missions does not dictate 

requirements for future missions; formal 

logistics item needs for those missions will 

be determined based on detailed mission 

requirements. However, the process described 

here provides a comparable initial estimate of 

logistics item needs.

Composition of Logistics Items

Logistics items are all the equipment and 

supplies needed to support mission activities 

and are not part of a vehicle or element dry 

mass, with the exception of vehicle propellant 

and pressurants, which are not considered to 

be logistics items. Logistics items can be divided 

into the following categories: 

Consumables: Includes all commodities that 

support the conduct of mission activities 

(often related to mission crew needs) that are 

not related to a specific payload or research 

activity. In some cases, this category also 

includes consumables driven by non-crew 

activities (e.g., air to account for air leakage 

and re-pressurizations). Examples of specific 

items include food, clothing, personal items, 

operational supplies, hygiene items, trash bags 

and other waste collection, towels, extravehicular 

activity consumables, and gases and liquids. 

Maintenance items: Includes planned 

replacement hardware and associated tools for 

system components that have known limited 

lifetimes and have scheduled replacement 

plans. Planned maintenance needs are largely 

system dependent. 

Spares: Includes spares and associated tools 

that address corrective maintenance for 

unexpected/unplanned failures of system 

hardware. The actual spares needs will depend 

on the system. 

Utilization (payloads and research): Additional 

hardware and items (e.g., science, research, 

capability demonstration, outreach) that take 

advantage of the space-based architecture but 

are not required for crew or vehicle operations. 

For exploration mission planning, mass and 

volume allocations are typically defined rather 

than specific utilization hardware, as the latter 

often depends on specific mission objectives. 

Outfitting: Subsystem hardware or components 

that are flown after the initial module delivery 

for permanent installation or use are defined 

as outfitting. As items are identified for 

outfitting, they are typically tracked as part of 

the integrated logistics plan. Outfitting often 

occurs when there are insufficient resources to 

implement all the desired functions within the 

initial launch mass or schedule, so key systems 

are delivered on alternate flights. Specific 

outfitting estimates depend on the mission. 

Packaging, overhead, and carriers: Materials 

required to safely and effectively transport and 

store each of the logistics items. (This category 

does not include any spacecraft secondary 

structures required to house or contain logistics 

items). 

National Aeronautics and

Space Administration

2023 Moon to Mars Architecture Concept Review 1white paper 2023 Moon to Mars Architecture

Lunar Logistics

Drivers and Needs
2023 Moon to Mars Architecture Concept Review 2

Lunar Logistics Drivers

Lunar mission logistics item needs are a function of the 

candidate mission and the proposed mission architecture. 

Although logistics item needs are determined by many 

factors, there are a few key contributors that have a 

predominant impact on overall logistics item needs. 

Typically, mission duration, crew size, environmental 

control and life support system (ECLSS) architecture, and 

extravehicular activity (EVA) cadence are the primary 

drivers. Mission crew size and mission duration are 

generally the most significant factors in determining the 

mass of logistics items. A large fraction of logistics item 

needs stems from crew support; these needs increase 

with the number of crew members and the mission 

duration. 

The proposed ECLSS architecture is also an important 

consideration. An open-loop ECLSS, where waste products 

are not collected and recycled, will result in large needs 

for gas and water consumables. A regenerative ECLSS, 

where some waste products are recycled to produce 

water and gas, can significantly reduce or even eliminate 

gas and water resupply needs.

Crew EVAs on lunar missions can also be a significant 

driver of logistics item needs. EVA systems use 

significant amounts of water, oxygen, and other dry 

consumables. In addition, maintenance items, spares, and 

tools are required to maintain EVA systems. For missions 

with many planned EVAs, such as lunar surface missions, 

the overall EVA support mass can be a significant fraction 

of overall logistics item mass. 

Logistics Item Estimates

Figure 1 shows approximate logistics item needs for 

representative lunar surface mission of varying crew sizes 

and mission durations. These estimates are for the mass 

of logistics items themselves and do not include carrier 

overhead mass. The uncertainty in the estimates shown 

in Figure 1 represents potential variability in mission 

operations and architecture. Changes in EVA cadence, 

ECLSS architecture, and element design can have 

substantial impacts on overall logistics item needs. While 

logistics item needs increase with crew size and mission 

duration, the increase is not linear, as certain fixed items 

are needed regardless of duration or crew size.

Figure 2 shows a representative breakdown by mass of 

logistics needs for a conceptual lunar surface mission 

with a significant planned cadence of EVAs. In this 

example, the habitation sub-architecture utilizes a fully 

open-loop ECLSS with no waste recycling. The water 

and gases needed to support the mission, including 

Figure 1. Approximate Logistics Item Needs for Representative Lunar Surface Missions
2023 Moon to Mars Architecture Concept Review 3

those for EVA, represent about half of the total logistics 

needs. Crew food and other crew consumables and EVA 

support items each represent about 20 percent of the 

overall needs. System maintenance and spare items and 

utilization items make up the remaining needs.

As missions progress to longer durations, spares and 

maintenance items can become larger drivers of overall 

logistics mass.

The ECLSS sub-architecture can have a significant impact 

on the overall distribution and total logistics item needs. 

With a high level of closure, the oxygen and water 

needs described in Figure 1, totaling almost 40 percent 

of overall needs, could be largely eliminated. However, 

regenerative ECLSS will generally increase subsystem 

mass and logistics item needs for maintenance and 

spares items.

The use of in-situ resource utilization capabilities can also 

have a substantial impact on logistics resupply. While insitu resource utilization does not reduce the need for 

logistics items, it can reduce the need to deliver certain 

items, such as water and gas, to the exploration location.

Note that the mass of packaging, overhead, and carriers 

is not included in Figure 1. The bags, foam, and tanks 

that contain cargo items, as well as the pressurized 

carriers needed to deliver logistics to the lunar surface 

can add a large amount of overhead beyond the mass 

of the logistics items themselves. Based on historical 

performance, this added overhead could be between 75 

percent and 150 percent of the base logistics item mass. 

However, the carrier mass depends heavily on the design 

of bags, tanks, and carriers. 

Summary

As the exploration architecture is conceptualized and 

planned, it is imperative to accurately predict logistics 

resupply needs. The total amount of logistics items 

required to keep the crew alive and healthy, to maintain 

systems, and to perform productive science and utilization 

can be relatively large. It can also heavily influence the 

design of the architecture and exploration missions. The 

architecture must therefore be based on comprehensive, 

accurate estimates of logistics item needs and include 

assessment of a suitable logistics sub-architectures to 

deliver those needs. 

Figure 2. Open-Loop Mass Breakdown Example

Key Take-Aways

Logistics items are all equipment and supplies not initially delivered as part of a vehicle or 

element dry mass that are needed to support mission activities.

Crew size, mission duration, ECLSS sub-architecture capabilities, and planned EVA cadence are 

the primary drivers for the total logistics needs.

Water, gases, and food dominate overall logistics needs by mass. 

The amount of logistics items that exploration missions require to keep the crew alive and 

healthy, to maintain systems, and to perform productive science and utilization is significant, 

and therefore it is important that the design and planning of the exploration architecture 

include comprehensive, accurate estimates of logistics item needs.