This paper provides a brief overview of the 

science enabled both by conducting analyses in 

situ on the lunar surface and by returning lunar 

samples to Earth. Several examples illustrate 

how both in-situ and returned sample analyses 

can address the lunar/planetary science (LPS) 

goals of the Moon to Mars Objectives. 

These examples represent only a snapshot 

of the extensive breadth and depth of LPS 

and other lunar surface sample-dependent 

objectives. Other lunar science objectives 

facilitated by geophysical instruments (e.g., 

seismometers, heat probes, magnetometers, 

laser reflectometers), which by their nature 

require in-situ analyses, are not discussed in 

the context of in-situ analyses versus mass 

of returned samples. However, sample return 

may provide supplementary context for 

interpretation of those geophysical results. 

The question of in-situ analyses versus mass of 

returned samples needs to be addressed on a 

case-by-case basis for each science goal. The 

strengths and weaknesses of each approach 

mean they are rarely directly interchangeable, 

and this variability should be taken into 

consideration during architecture definition. 

Broad Artemis and Moon to Mars goals will best 

be achieved by an integrated strategy that uses 

both sample return and in-situ measurements.

National Aeronautics and

Space Administration

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

Introduction

The emerging capabilities of NASA and its commercial and international partners to land significant 

payloads on the surface of the Moon will provide opportunities to land large and diverse suites 

of science instruments. It will also provide opportunities to return samples to Earth for scientific 

analyses in Earth-based laboratories. 

During the Apollo Program, the return of samples to Earth was the only viable way to obtain 

accurate and precise mineralogical and geochemical analyses of lunar samples; technology was 

simply not available or mature enough to enable these detailed scientific investigations in situ. 

As mission capabilities improve, architecture is refined, and analytical technologies improve with 

NASA’s return to the Moon with the Artemis missions, a question arises: 

Can modern payloads to the Moon provide sufficient analytical 

capabilities to replace the need for return of samples to Earth?

Analytical Capabilities In Situ Versus Mass

of Returned Lunar Samples

Lunar/Planetary Science Objectives

Goal: Address high priority planetary science 

questions that are best accomplished by on-site 

human explorers on and around the Moon and 

Mars, aided by surface and orbiting robotic systems.

LPS-1: Uncover the record of solar system origin 

and early history, by determining how and when 

planetary bodies formed and differentiated, 

characterizing the impact chronology of the inner 

solar system as recorded on the Moon and Mars, 

and characterize how impact rates in the inner solar 

system have changed over time as recorded on the 

Moon and Mars. 

LPS-2: Advance understanding of the geologic 

processes that affect planetary bodies by 

determining the interior structures, characterizing 

the magmatic histories, characterizing ancient, 

modern, and evolution of atmospheres/exospheres, 

and investigating how active processes modify the 

surfaces of the Moon and Mars.

LPS-3: Reveal inner solar system volatile origin and 

delivery processes by determining the age, origin, 

distribution, abundance, composition, transport, 

and sequestration of lunar and Martian volatiles.

LPS-4: Advance understanding of the origin of life in 

the solar system by identifying where and when 

potentially habitable environments exist(ed), what 

processes led to their formation, how planetary 

environments and habitable conditions have coevolved over time, and whether there is evidence of 

past or present life in the solar system beyond Earth.
2023 Moon to Mars Architecture Concept Review 2

Lunar Samples as Unique

But Complex Records

The Moon serves as a historical archive for the Earth 

and inner solar system, recording events that happened 

billions of years ago. 

Geological processes on Earth — such as plate tectonics 

and erosion by wind and rain — have erased all but a 

few rocks from the first billion years of Earth’s history. 

By contrast, the Moon lacks major ongoing geological 

activity, with the exception of surface modification by 

impact events and space weathering. The Moon’s major 

structural characteristics, including core formation, crustal 

formation, and the freezing of the interior structure, were 

largely established about 4 billion years ago, with major 

volcanic events complete by about 3 billion years ago. 

Samples of the Moon therefore preserve unique records 

of the most ancient history of the Earth-Moon system and 

of the inner solar system (including Mars). Fundamental 

science achieved through analysis of lunar samples 

includes, but is far from limited to: 

• Understanding the evolution of rocky planetary 

bodies.

• Establishing absolute ages of cratered surfaces 

throughout the solar system.

• Understanding the space weathering of airless bodies 

in the solar system.

• Constraints on the formation locations and later 

adjustments in orbits of the gas giants. 

• Improved understanding of our solar system’s history 

as it revolved around the Milky Way galaxy. 

Lunar samples also provide information regarding the 

origin and evolution of volatiles on the Moon and Mars, 

with implications for both in-situ resource utilization and 

science. 

While documents such as the Artemis III Science Definition 

Report and the Moon to Mars Objectives (e.g., LPS 1–4) 

capture many major science goals, the scope of science 

achievable through lunar (and Mars) sample analyses is 

vast. This is especially true for returned samples, which 

can be studied with ever-improving instrumentation to 

address new science questions for many decades after 

the completion of the original mission.

Unlocking the events and processes recorded by lunar 

samples includes a significant challenge: the history 

preserved in each rock is extremely complex. Unravelling 

this complexity requires detailed knowledge of the 

samples’ origins and locations, careful preparation of 

samples, detailed sample characterization, and many 

types of analyses with high accuracy, high precision, and 

high spatial resolution. Obtaining this knowledge will 

require many specialized types of analytical techniques 

and instruments.

Prerequisites for Analysis: Finding and

Preparing the Right Material for Analysis

Lunar samples are chemically and mineralogically diverse 

(Figure 1), as demonstrated by the many different types of 

rocks collected during each Apollo mission, as well as the 

overall diversity of the Apollo sample collection. Much of 

this diversity was captured because of the relatively large 

mass returned and the multiple, geologically different 

sampling locations. 

Even with more than 2,200 individual samples totaling 

382 kg, many types of samples were only represented by 

a few grams of material or just a single sample (e.g., green 

and orange volcanic glass beads from Apollo 15 and 17, 

respectively; troctolite from Apollo 17, from deep in the 

Moon’s crust; anorthosite from Apollo 15 [Genesis rock]), 

and many more sample types were likely unaccounted 

for in the collection. Addressing the breadth of science 

questions encompassed by the Moon to Mars Objectives 

requires analyses of many different types of samples 

present within a given terrain, which can be collected 

either by crewed extravehicular activity or uncrewed 

rovers.

Figure 1. Apollo sample 60019 (top) is a breccia with 

distinct light and dark clasts. Other samples, such as 60025 

(bottom) appear more uniform at the surface but overlaid 

X-ray imaging of the interior (lower right portion of the 

sample) reveals pervasive heterogeneity. Both samples 

were collected during Apollo 16. (Images from NASA’s 

Astromaterials 3D project). 
2023 Moon to Mars Architecture Concept Review 3

Achieving science goals requires analyses not just of these 

representative bulk samples but of the many pieces that 

make up each rock — individual minerals, grains, clasts, 

etc. Each rock is like a puzzle with hundreds of pieces, 

and each piece, or sub-sample, sheds light on a different 

part of the story. 

Sub-sample components can record distinct and specific 

processes — for example, zircon is a key mineral for 

chronology (LPS-1), apatite and other minerals retain 

volatiles from magmatic/volcanic processes (LPS-2), 

glasses and agglutinates can record surface processes 

(LPS-1, 3), and rare dunitic and granitic clasts record a 

much broader range of magmatic and volcanic events 

than basalt alone (LPS-2). Exploring the lunar South Pole 

region and associated permanently shadowed regions 

will require analyses of regolith, rocks, and ices of 

different origins, which were deposited and sequestered 

by different natural mechanisms throughout the Moon’s 

history (LPS-3).

In-situ analyses – 

Collection of samples is best conducted in concert with 

broader surface geological investigations, such as by 

trained crew and/or with in-situ instruments. Together, 

these provide better context for the site from which a 

sample is collected. 

Geologic context is crucial for the correct interpretation 

of analyzed samples. Continued development of in-situ 

techniques could rapidly identify the diversity of materials 

within and between terrains. 

If fast and accurate enough, these techniques could help 

ensure that collected samples — whether for return to 

Earth or further in-situ analyses — include all scientifically 

important components. For example, astronauts or rovers 

could target the collection of low-abundance materials in 

a site otherwise dominated by another sample type. This 

could reduce the need for “luck” or for collecting vastly 

more sample mass than needed.

A limited amount of sample preparation (e.g., grinding 

to smaller fragments or powder, heating, chemical 

digestion) may be required for some in-situ analyses, 

as the Mars rovers have demonstrated. However, many 

lunar samples (e.g., Figure 1) exhibit such complex, smallscale heterogeneity that comprehensive, in-situ sample 

preparation will likely be impractical in many situations. 

Some lunar science goals will require delivery of a 

prepared, high-quality sample to a suitably accurate and 

precise instrument.

Returned samples – 

For Apollo samples, tens of thousands of component 

pieces have been painstakingly extracted and prepared 

for laboratory analyses. This work has been conducted 

across five decades by the sample processing team at 

curation facilities at NASA’s Johnson Space Center in 

Houston and hundreds of scientists in other labs around 

the world. 

The analysis and cataloging of these samples involves 

many hours of work in various combinations of 

separation, extraction, chemical processing, and other 

means of preparation for each individual sample. 

Different combinations of sample preparation are 

implemented for different types of scientific analysis. For 

many types of analysis, a final step in sample preparation 

is dissolving a sample in acid (e.g., nitric acid, hydrochloric 

acid, hydrofluoric acid), which allows individual elements 

to be filtered and separated for analysis by increasingly 

sophisticated and capable mass spectrometers. For 

all these complexities and more, the return of samples 

to Earth will remain central to lunar science for the 

foreseeable future.

Sample Characterization

There have been over 3,380 separate studies of the Apollo 

samples over the past 50+ years. They have yielded many 

thousands of scientific papers, which is a testament to the 

complexity and the long-term value of returned samples. 

Sample characterization — that is, gaining a better 

understanding of the basic nature of individual puzzle 

pieces and how the puzzle pieces fit together — is an 

essential step in studying returned lunar samples. The 

same is true for returned asteroid samples and lunar and 

Martian meteorites and is expected for the Mars Sample 

Return mission. 

Optical microscopy provides magnified views of the 

sample surface. X-ray computed tomography enables 

views of the interior of samples to record the position of 

pieces and informs decisions about where to slice open a 

sample (just as dentists and doctors use X-rays to inform 

treatment plans). Following mechanical preparation, 

researchers use additional optical and electron 

microscopy technologies and various spectroscopies over 

a wide range of the electromagnetic spectrum to provide 

much higher resolution views of the sample interiors. 

Once basic sample characterization is complete, more 

detailed types of analyses can be conducted to evaluate 

the history of the sample and its components. For 

example, scanning electron microscopes and electron 

microprobes enable chemical and mineralogical analyses 

at nanometer to micrometer scales. At these scales, 

important records of lunar processes are recorded by 

variations in chemistry and mineralogy. Similarly, focused 

ion beam instruments enable extraction of electrontransparent wafers for analysis by transmission electron 

microscopy. This method provides exceptionally detailed 

views of chemical and mineralogical variations at subnanometer resolution. 

These are workhorse techniques — required analytical 

capabilities — for understanding lunar samples. The 

data produced by these techniques are imperative for 

achieving many Moon to Mars Objectives.
In-situ analyses – 

The development of miniaturized scanning electron 

microscopes (e.g., Mochii, which flew on the International 

Space Station) demonstrates a viable future path for 

some detailed sample characterization in situ, albeit with 

some limitations regarding surface sample preparation. 

Other techniques, such as laser Raman spectroscopy, 

have been deployed on Mars rovers and provide similar 

opportunities for characterizing sample chemistry. 

However, techniques like X-ray computed tomography 

have yet to be employed in a mission setting but could 

provide useful information on the 3D interior structure 

and mineralogy of lunar samples in the future. Example 

use cases would include uncrewed missions or extendedduration stays; sample triaging would require significant 

improvements in speed and automation to be useful on 

shorter missions.

Returned samples – 

Many sample characterization techniques require longduration analyses (hours to days) to study even a few 

millimeters of material. Other techniques for sample 

characterization are currently far beyond the capabilities 

of in-situ instruments. 

For example, characterizing very small but significant 

features (e.g., delicate surface structures, diagnostic 

chemical zonation at mineral boundaries) requires 

techniques such as transmission electron microscopy 

and associated focused ion beam preparation. The size, 

complexity, and underlying technologies of this method 

would be extremely challenging to miniaturize for flight.

The use of synchrotron facilities, requiring kilometerscale light paths, enables exceptional chemical and 

mineralogical investigations at high spatial resolution, 

with applications to lunar science goals ranging from 

understanding magmatism to exploring the effects 

of space weathering. It is currently unfathomable to 

miniaturize the enormous infrastructure supporting such 

facilities for in-situ analyses.

Accuracy and Precision

Essentially every element in the periodic table has value 

in lunar science. For example, volatile elements, such 

as hydrogen, and dozens of related molecules (e.g., H, 

OH, H2O, CH4, NH3) are integral to Artemis science and 

exploration objectives in the lunar South Pole region. 

Hydrogen is also one of almost 60 elements that have 

more than one stable isotope (elements with the same 

atomic number but additional neutrons resulting in 

different atomic mass). For these elements, fractionation 

of light and heavy isotopes preserves the effects of 

important physical and chemical processes (e.g., melting, 

evaporation, crystallization, metal-silicate fractionation 

during core formation). 

Many elements also have unstable isotopes, some of 

which yield useful systems for radiometric dating (e.g., 

U-Pb, Sm-Nd, Rb-Sr, K-Ar). This dating provides ages that, 

at the right levels of precision, can answer questions of 

when key events happened in a moon or planet’s history, 

ranging across primary formation, impact modification, 

and surface exposure. 

In-situ analyses – 

While many science goals require accuracy and precision 

beyond the capabilities of current flight hardware, some 

science goals are ideal for in-situ analyses. One such 

example is the Dating an Irregular Mare Patch with a 

Lunar Explorer (DIMPLE) instrument suite, which was 

selected in 2023 for funding by NASA’s Payloads and 

Research Investigations on the Surface of the Moon 

(PRISM) program. 

DIMPLE will be delivered to the Moon by a Commercial 

Lunar Payload Services (CLPS) lander. Its instrument suite 

includes the Chemistry Organic and Dating Experiment 

(CODEX), which will yield the first in-situ dating of samples 

on the lunar surface. 

CODEX has an estimated precision of ± 375 million years, 

leveraging the rubidium-strontium (Rb-Sr) radiometric 

system. While this precision would not be suitable for 

most lunar chronology analyses, it is sufficient to achieve 

the specific goal of the mission: determining whether the 

unique terrain of Ina, an unusual depression on the lunar 

surface, is ancient (approximately 3.75 billion years) or 

young (approximately 10–100 million years).

Other in-situ analyses, such as the detection of volatiles 

(e.g., water), are central to other CLPS missions, NASA’s 

Volatiles Investigating Polar Exploration Rover (VIPER), 

and multiple concept missions and instruments. Volatiles 

are central to many science goals and to the broader 

Moon to Mars Objectives. Low-mass, uncrewed missions 

can explore far more sites and the results can inform 

strategic site selection for larger and crewed missions in 

the future.

Returned samples – 

Laboratories on Earth have significantly higher accuracy 

and precision than is possible with in-situ instruments. In 

most instances, this accuracy and precision is required to 

answer driving science questions. 

For example, the vast majority of questions regarding the 

ages of terrains, regions, and volcanic or impact events on 

the Moon (LPS-1,2,3; e.g., the age of the South Pole-Aitken 

basin) require significantly better precision than current 

flight instruments offer. For comparison, laboratories 

on Earth in the Apollo era had comparable precision to 

CODEX, while modern terrestrial laboratories are capable 

of Rb-Sr dating with precision of approximately 30 million 

years, 10 times better than the CODEX instrument. 

2023 Moon to Mars Architecture Concept Review 4
Further, Rb-Sr is just one dating technique; it is appropriate 

for understanding only a subset of events and processes 

that have occurred throughout lunar history. The return 

of samples enables researchers to apply multiple dating 

techniques (e.g., K-Ar, Sm-Nd, U-Pb) to multiple mineral 

phases even within a single rock sample; this is important 

because some isotopic systems are more prone to 

resetting during impact events than others. 

Similar scenarios exist for other elemental and 

molecular analyses. For example, understanding the 

origin and evolution of volatiles, both for science and 

in-situ resource utilization, may require analyses of lowabundance elements and at levels of isotopic precision 

that are difficult to achieve through in-situ analyses. 

Return of samples to Earth enables many different 

types of specialized instruments to study each element, 

isotope, and molecule. Essentially every instrument on 

Earth becomes part of the analytical suite. 

Development of different instruments enables 

researchers to tailor analytical conditions to maximize 

the accuracy and precision of a specific analysis. Many of 

these instruments rely on exceptionally heavy magnets 

to provide sufficient mass separation between different 

isotopes. Even a small suite of mass spectrometers 

capable of measuring a handful of groups (e.g., light 

elements, transition metals, heavy radiogenic isotopes, 

noble gases) requires many metric tons. 

Researchers need these instruments and dedicated 

components because of the very slight differences in 

chemistry that are imparted by geological processes — 

often variations measured in parts per million or parts 

per billion. 

Suites of Instruments

It is common practice — and essential for achieving 

many scientific goals — to analyze the same sample 

with multiple techniques. This enables researchers to 

place the different puzzle pieces in the right context, 

(e.g., which are older or younger, which formed at higher 

temperatures, which formed close together, which were 

brought together by a later impact event). 

In-situ analyses – 

The development of an architecture that supports larger 

payloads opens the possibility of landing instrument 

suites for in-situ analyses. Such an approach can enable 

detailed sample science in the absence of sample return. 

The Mars rovers exquisitely demonstrate the level of 

science that can be achieved by integrating results from 

multiple types of instruments. CLPS, autonomous rovers, 

and crew deployment will provide multiple opportunities 

for the development and implementation of such 

instrument suites for the Moon. The deployment of 

carefully selected instrument suites could offer excellent 

site context, answer a subset of science questions, inform 

future mission decisions, and support contemporaneous 

or future sample return activities.

Returned samples – 

Just as with the Mars rovers, even long-duration 

exploration with a comprehensive instrument suite will 

leave many significant science questions unanswered. 

The expense and complexity of the Mars Sample Return 

mission is well known, yet the call for the mission continues 

for a simple reason: in-situ instruments cannot match the 

fidelity of science enabled by returned samples. 

The same is true for the Moon and, thankfully, the return 

of samples from the lunar surface is highly feasible. 

Returned samples allow researchers to employ many 

different approaches on the same sample and multiple 

sub-samples using dozens of instruments across the best 

laboratories on Earth. 

Such approaches enable deep understanding of how, 

where, and when a sample was formed — and what 

this tells us about the origin and evolution of the Moon, 

as well as other bodies within the solar system. A huge 

advantage of returned samples is that they also enable 

new analyses to be conducted as technology develops 

over many decades. 

Beyond Geology-Based Science

The bulk of this paper is dedicated to sample science 

from a broad geological perspective, but similar needs 

for sample return exist in other disciplines. 

For biological and physical sciences conducted on the 

lunar surface or in cislunar orbit, the return of specimens 

for detailed analyses in Earth-based laboratories is 

critical. Biological investigations require different 

types of analyses at various levels of physiology. These 

identify underlying root mechanisms both affected 

by and governing responses to the space exploration 

environment by understanding impacts to individual and 

integrated multi-organ systems. 

Microbiology ecosystem and pathogenicity investigations 

require analysis of individual specimens at the genetic 

level through host-microbial interactions and microbeto-microbe interactions. In-situ analyses will provide 

important rudimentary data that requires more 

expansive follow-up analyses using instruments and 

techniques that, for now, are only available in Earthbased laboratories. 

In addition, the return of specimens will require either 

live return or conditioned stowage (freezers), which 

enables high-fidelity preservation of the specimens 

for morphology, biochemical, and molecular biological 

analyses. Cold stowage may also be required for the 

transport of accessory chemicals and solutions for in-situ 

analysis instruments and of the specimens themselves. 

2023 Moon to Mars Architecture Concept Review 5
Although much of the data and imagery for physical 

sciences investigations can use telemetry back to 

Earth, some investigations will require sample return 

to complete the analyses. For example, elements and 

materials used for combustion and flammability studies 

will require post-burn analyses to understand and develop 

models for propulsion and fire safety. Products created 

from science instruments examining the fundamental 

properties of materials, braising, volatile extraction, and 

soft matter/granular flow and particles are important to 

close knowledge gaps for development of lunar in-situ 

resource utilization methods and processes. These must 

be analyzed in Earth-based laboratories with instruments 

capable of the depth of analyses required. In addition, 

if telemetry bandwidth is limited, the return of data 

recorders and memory cards will be required. 

Collectively, the return of specimens and samples from 

the Moon is important to gain a complete understanding 

of biological and physical systems. This understanding is 

critical to advancement of scientific knowledge, closure 

of knowledge gaps, and development of biological and 

predictive models that can be used to advance safe and 

productive human exploration, deep space travel, and 

long-term self-sustaining habitation on the Moon and 

other worlds. 

2023 Moon to Mars Architecture Concept Review 6

Conclusion

Sample return is an absolute necessity to properly achieve the lunar/planetary science goals of 

the Moon to Mars Objectives. Returned samples enable analyses by the world’s best laboratories 

and instruments, supported by teams of scientists and engineers. Returned samples will also 

serve as ongoing resources to the worldwide scientific community for the coming decades, 

enabling fundamental insights into the Moon and other bodies in our solar system.

In-situ analyses/instruments can address a subset of the lunar/planetary science goals, and 

deployment of in-situ instruments to multiple lunar terrains during low-mass, uncrewed missions 

will provide broader insights than can be achieved through larger and/or crewed missions alone. 

Many of the inherent limitations of in-situ analyses (e.g., sample preparation, accuracy and 

precision, time needed for analyses) mean that even a fleet of in-situ instruments would not 

currently address many lunar science goals. However, continued development of in-situ 

instruments will ensure that they are capable of more and more unique, standalone science in 

the future. Further, as we test and develop in-situ technologies on the Moon during the early 

Artemis missions, NASA can leverage these expanding capabilities for long-duration crewed 

missions to the Moon and future missions to Mars.

Overall, the most efficient strategy for lunar science and exploration includes careful integration 

of in-situ analyses and sample return. Current and anticipated near-term in-situ analytical 

capabilities do not replace the need for sample return; the balance between the two should be 

carefully considered on a case-by-case basis, with science representatives involved in all stages 

of mission concept and architecture definition.