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# Terrestrial Analogs: Using Earth to Study Space

Did you know the USGS uses sites on Earth to study space? These locations are called terrestrial analogs, and can be used for many different things like conducting research, teaching, and testing instruments. Learn more about terrestrial analogs and space science below!

                  -              Overview           
                  -              Publications           
                  -              Data and More           
                  -              Maps           
                  -              News           

#### What is a terrestrial analog?

Planetary scientists study bodies across the solar system. While it would be very helpful to visit these locations and study them directly, traveling to these locations is difficult, time consuming, and expensive. Fortunately, the Earth displays many similar landforms and geologic processes (for example, volcanic eruptions) that are also observed on other planetary bodies. These locations on Earth (called *terrestrial analogs*) can be studied more easily than other planetary bodies, and the basic geologic principles can then be used to better understand similar sites across the solar system. Terrestrial analogs can be used for a wide variety of science investigations, but also for training, technology demonstrations, route (*traverse*) planning, and field simulations.

View Media Details

#### How does the USGS use terrestrial analogs?

#####  

##### *Understanding geologic processes*

View Media Details

Learn more about how USGS scientists use Iceland to study Mars!

Since planetary scientists can't visit the places they study, they often use similar locations here on Earth (*terrestrial analogs*) to better understand the geologic processes that are occurring. This includes locations like dune fields, volcanoes, rivers and lakes, impact craters, and glaciers. By studying the processes that create these features on Earth, planetary scientists can then take what they know about how these features form and use it to interpret similar features on other planetary bodies. Sometimes the feature is made of a different material than it is on Earth (for example, water-based volcanism - "cryovolcanism" - on icy bodies in the outer solar system). Understanding how a geologic process works on Earth also helps planetary scientists understand how those different materials may affect it on another body.

Learn more about how USGS scientists use terrestrial analogs to study our solar system.

Terrestrial Analogs for Research and Geologic Exploration Training

## Terrestrial Analogs for Research and Geologic Exploration Training

Terrestrial analogs data portal

## Terrestrial analogs data portal

Terrestrial Analog Sample Collection

## Terrestrial Analog Sample Collection

##### *Training and testing*

Every astronaut that has ever walked on the Moon trained with the USGS in Flagstaff, Arizona. Terrestrial analogs like Cinder Lake crater field, Sunset Crater, the Grand Canyon, and Meteor Crater were used to teach astronauts the importance of geology, how to understand landforms and the processes that make them, and how to create a geologic map. Terrestrial analog sites were critical in preparing the astronauts to explore the surface of the Moon safely, while also making valuable scientific observations for the scientists back on Earth. These pre-mission practices were an opportunity to learn and practice on terrain that was similar to the Moon, without the risk or expense of space travel. In fact, the USGS even made an exact copy of two locations on the Moon! Cinder Lake Crater Field was created with carefully planned explosives, and was an exact copy of two of the possible Apollo landing sites.

View Media Details

Along with astronaut training, instruments, roving vehicles, and traverse logistics were also tested at these sites. Grover the Geologic Rover was a prototype of the Lunar Roving Vehicle, and was used by Apollo 15, 16, and 17 to practice traversing across the "lunar surface" near Flagstaff. Today, you can find Grover proudly on display at the USGS Astrogeology Science Center in Flagstaff.

View Media Details

Today, the USGS is using terrestrial analogs to help prepare the Artemis mission return to the Moon! Learn more about the USGS and mission operations here.

#### What are some commonly used analog sites?

Click the images below to learn about some of the commonly used analog sites in northern Arizona. These sites are used in many ways, including traverse testing and technology demonstrations (SP Mountain, Hopi Buttes, Cinder Lake Crater Field), radiation protection for astronauts and cave microclimates (Lava River Cave), volcanism on other planetary bodies (SP Mountain, Sunset Crater), and water-lava interactions (Verde Valley).

Meteor Crater

## Meteor Crater

Cinder Lake Crater Field

## Cinder Lake Crater Field

SP Mountain

## SP Mountain

Sunset Crater

## Sunset Crater

Grand Falls

## Grand Falls

San Francisco Volcanic Field

## San Francisco Volcanic Field

Lava River Cave

## Lava River Cave

Verde Valley

## Verde Valley

Grand Canyon

## Grand Canyon

## Publications

August 19, 2021

####                 A geologic field guide to S P Mountain and its lava flow, San Francisco Volcanic Field, Arizona              

Natural Hazards Mission Area, Volcano Hazards Program, Volcano Science Center, Astrogeology Science Center

January 1, 2009

####                 Assessment of planetary geologic mapping techniques for Mars using terrestrial analogs: The SP Mountain area of the San Francisco Volcanic Field, Arizona              

Natural Hazards Mission Area, Astrogeology Science Center

January 1, 2005

####                 The U.S. Geological Survey, branch of Astrogeology - a chronology of activities from conception through the end of Project Apollo (1960-1973)              

April 1, 2001

####                 The San Francisco volcanic field, Arizona              

August 7, 1974

####                 Guidebook to the geology of Meteor Crater, Arizona              

View All

## News

From Earth to Space:  Astrogeology team tell Denver7 News how they use Terrestrial Analog sites to study our Solar System!

December 22, 2022

####   From Earth to Space:  Astrogeology team tell Denver7 News how they use Terrestrial Analog sites to study our Solar System!

A Martian landscape right at home

August 16, 2022

####   A Martian landscape right at home

A Virtual Field-trip Guide to S P Mountain Just Released by Astrogeology Science Center!

September 29, 2021

####   A Virtual Field-trip Guide to S P Mountain Just Released by Astrogeology Science Center!

View All

August 19, 2021

####                 A geologic field guide to S P Mountain and its lava flow, San Francisco Volcanic Field, Arizona              

Natural Hazards Mission Area, Volcano Hazards Program, Volcano Science Center, Astrogeology Science Center

January 1, 2009

####                 Assessment of planetary geologic mapping techniques for Mars using terrestrial analogs: The SP Mountain area of the San Francisco Volcanic Field, Arizona              

Natural Hazards Mission Area, Astrogeology Science Center

January 1, 2005

####                 The U.S. Geological Survey, branch of Astrogeology - a chronology of activities from conception through the end of Project Apollo (1960-1973)              

April 1, 2001

####                 The San Francisco volcanic field, Arizona              

August 7, 1974

####                 Guidebook to the geology of Meteor Crater, Arizona              

January 1, 1967

####                 Cinder Lake crater field location test              

January 1, 1959

####                 Impact mechanics at Meteor Crater, Arizona              

February 17, 2023

####                 Meteor Crater, Northern Arizona: Drill Hole Sample Collection, 1970-1973, and Curation, 2010-2013              

Astrogeology Science Center

October 15, 2020

####                 Grand Falls, Arizona: Dune Field Sand Transport 2017 - 2019              

Astrogeology Science Center

October 15, 2020

####                 Grand Falls, Arizona: Dune Field Sand Transport 2013 - 2016              

Astrogeology Science Center

January 1, 1987

####                 Geologic map of the SP Mountain part of the San Francisco Volcanic Field, north-central Arizona              

San Francisco Volcanic Field

From Earth to Space:  Astrogeology team tell Denver7 News how they use Terrestrial Analog sites to study our Solar System!

December 22, 2022

####   From Earth to Space:  Astrogeology team tell Denver7 News how they use Terrestrial Analog sites to study our Solar System!

Do you want to know how and why scientists use terrestrial analogs to do research and explore space? Watch this quick video of physical scientist Ryan...

Read Article

A Martian landscape right at home

August 16, 2022

####   A Martian landscape right at home

USGS researchers are studying glacial features in Iceland to help reveal past climates on Mars as part of a larger effort to use terrestrial analogs...

Read Article

A Virtual Field-trip Guide to S P Mountain Just Released by Astrogeology Science Center!

September 29, 2021

####   A Virtual Field-trip Guide to S P Mountain Just Released by Astrogeology Science Center!

If you are interested in volcanology,  you should check out our newly-released virtual S P Mountain Field Guide. S P Mountain is a textbook example of...

Read Article

Local Grand Falls Dunes in the Eyes of Scientific Research

August 9, 2021

####   Local Grand Falls Dunes in the Eyes of Scientific Research

The Grand Falls Dunes are approximately 2 km from Grand Falls.  USGS scientists are studying the Grand Falls Dunes not only to benefit the people who...

Read Article

The truth about a terrifying lava skylight where only the trained should lurk

October 4, 2020

####   The truth about a terrifying lava skylight where only the trained should lurk

A lava skylight is not seen by most people as being particularly scary since it is just an opening in the roof above a lava tube from which the...

Read Article

                  - Overview  What is a terrestrial analog?
Planetary scientists study bodies across the solar system. While it would be very helpful to visit these locations and study them directly, traveling to these locations is difficult, time consuming, and expensive. Fortunately, the Earth displays many similar landforms and geologic processes (for example, volcanic eruptions) that are also observed on other planetary bodies. These locations on Earth (called *terrestrial analogs*) can be studied more easily than other planetary bodies, and the basic geologic principles can then be used to better understand similar sites across the solar system. Terrestrial analogs can be used for a wide variety of science investigations, but also for training, technology demonstrations, route (*traverse*) planning, and field simulations.
        Sources/Usage: Public Domain. View Media DetailsHow does the USGS use terrestrial analogs? *Understanding geologic processes*        Sources/Usage: Public Domain. View Media DetailsUSGS scientist collecting elevation data to study a complex glacial system in Iceland. Learn more about how USGS scientists use Iceland to study Mars!
Since planetary scientists can't visit the places they study, they often use similar locations here on Earth (*terrestrial analogs*) to better understand the geologic processes that are occurring. This includes locations like dune fields, volcanoes, rivers and lakes, impact craters, and glaciers. By studying the processes that create these features on Earth, planetary scientists can then take what they know about how these features form and use it to interpret similar features on other planetary bodies. Sometimes the feature is made of a different material than it is on Earth (for example, water-based volcanism - "cryovolcanism" - on icy bodies in the outer solar system). Understanding how a geologic process works on Earth also helps planetary scientists understand how those different materials may affect it on another body.

Learn more about how USGS scientists use terrestrial analogs to study our solar system.
Terrestrial Analogs for Research and Geologic Exploration TrainingTerrestrial Analogs for Research and Geologic Exploration TrainingTerrestrial analogs data portalTerrestrial analogs data portalTerrestrial Analog Sample CollectionTerrestrial Analog Sample Collection*Training and testing*
Every astronaut that has ever walked on the Moon trained with the USGS in Flagstaff, Arizona. Terrestrial analogs like Cinder Lake crater field, Sunset Crater, the Grand Canyon, and Meteor Crater were used to teach astronauts the importance of geology, how to understand landforms and the processes that make them, and how to create a geologic map. Terrestrial analog sites were critical in preparing the astronauts to explore the surface of the Moon safely, while also making valuable scientific observations for the scientists back on Earth. These pre-mission practices were an opportunity to learn and practice on terrain that was similar to the Moon, without the risk or expense of space travel. In fact, the USGS even made an exact copy of two locations on the Moon! Cinder Lake Crater Field was created with carefully planned explosives, and was an exact copy of two of the possible Apollo landing sites.
        Sources/Usage: Public Domain. View Media DetailsAstronauts Jim Irwin (left) and Dave Scott practicing taking samples at Cinder Lake Crater Field during field training for Apollo 15.
Along with astronaut training, instruments, roving vehicles, and traverse logistics were also tested at these sites. Grover the Geologic Rover was a prototype of the Lunar Roving Vehicle, and was used by Apollo 15, 16, and 17 to practice traversing across the "lunar surface" near Flagstaff. Today, you can find Grover proudly on display at the USGS Astrogeology Science Center in Flagstaff.
        Sources/Usage: Public Domain. View Media DetailsApollo astronauts Charles Duke (left) and John Young (right) drive Grover outside Flagstaff, Arizona.
Today, the USGS is using terrestrial analogs to help prepare the Artemis mission return to the Moon! Learn more about the USGS and mission operations here.
What are some commonly used analog sites?
Click the images below to learn about some of the commonly used analog sites in northern Arizona. These sites are used in many ways, including traverse testing and technology demonstrations (SP Mountain, Hopi Buttes, Cinder Lake Crater Field), radiation protection for astronauts and cave microclimates (Lava River Cave), volcanism on other planetary bodies (SP Mountain, Sunset Crater), and water-lava interactions (Verde Valley).
Meteor CraterMeteor CraterCinder Lake Crater FieldCinder Lake Crater FieldSP MountainSP MountainSunset CraterSunset CraterGrand FallsGrand FallsSan Francisco Volcanic FieldSan Francisco Volcanic FieldLava River CaveLava River CaveVerde ValleyVerde ValleyGrand CanyonGrand CanyonPublicationsAugust 19, 2021                A geologic field guide to S P Mountain and its lava flow, San Francisco Volcanic Field, Arizona              IntroductionWe created this guide to introduce the user to the San Francisco Volcanic Field as a terrestrial analog site for planetary volcanic processes. For decades, the San Francisco Volcanic Field has been used to teach scientists to recognize the products of common types of volcanic eruptions and associated volcanic features. The volcanic processes and products observed in this volcanic fieldAuthorsAmber L. Gullikson, M. Elise Rumpf, Lauren A. Edgar, Laszlo P. Keszthelyi, James A. Skinner, Lisa ThompsonByNatural Hazards Mission Area, Volcano Hazards Program, Volcano Science Center, Astrogeology Science CenterJanuary 1, 2009                Assessment of planetary geologic mapping techniques for Mars using terrestrial analogs: The SP Mountain area of the San Francisco Volcanic Field, Arizona              We photogeologically mapped the SP Mountain region of the San Francisco Volcanic Field in northern Arizona, USA to evaluate and improve the fidelity of approaches used in geologic mapping of Mars. This test site, which was previously mapped in the field, is chiefly composed of Late Cenozoic cinder cones, lava flows, and alluvium perched on Permian limestone of the Kaibab Formation. Faulting and foAuthorsKenneth L. Tanaka, James A. Skinner, Larry S. Crumpler, James M. DohmByNatural Hazards Mission Area, Astrogeology Science CenterJanuary 1, 2005                The U.S. Geological Survey, branch of Astrogeology - a chronology of activities from conception through the end of Project Apollo (1960-1973)              No abstract available.AuthorsGerald G. SchaberApril 1, 2001                The San Francisco volcanic field, Arizona              Northern Arizona's San Francisco Volcanic Field, much of which lies within Coconino and Kaibab National Forests, is an area of young volcanoes along the southern margin of the Colorado Plateau. During its 6-million-year history, this field has produced more than 600 volcanoes. Their activity has created a topographically varied landscape with forests that extend from the Pi?on-Juniper up to the BrAuthorsS. S. Priest, W. A. Duffield, Karen Malis-Clark, J. W. Hendley, P.H. StaufferAugust 7, 1974                Guidebook to the geology of Meteor Crater, Arizona              No abstract available.AuthorsEugene Merle Shoemaker, Susan W. Kieffer, Robert L. SuttonView AllNewsFrom Earth to Space:  Astrogeology team tell Denver7 News how they use Terrestrial Analog sites to study our Solar System!December 22, 2022  From Earth to Space:  Astrogeology team tell Denver7 News how they use Terrestrial Analog sites to study our Solar System!A Martian landscape right at homeAugust 16, 2022  A Martian landscape right at homeA Virtual Field-trip Guide to S P Mountain Just Released by Astrogeology Science Center!September 29, 2021  A Virtual Field-trip Guide to S P Mountain Just Released by Astrogeology Science Center!View All 
                  - Publications  LabelAugust 19, 2021                A geologic field guide to S P Mountain and its lava flow, San Francisco Volcanic Field, Arizona              IntroductionWe created this guide to introduce the user to the San Francisco Volcanic Field as a terrestrial analog site for planetary volcanic processes. For decades, the San Francisco Volcanic Field has been used to teach scientists to recognize the products of common types of volcanic eruptions and associated volcanic features. The volcanic processes and products observed in this volcanic fieldAuthorsAmber L. Gullikson, M. Elise Rumpf, Lauren A. Edgar, Laszlo P. Keszthelyi, James A. Skinner, Lisa ThompsonByNatural Hazards Mission Area, Volcano Hazards Program, Volcano Science Center, Astrogeology Science CenterJanuary 1, 2009                Assessment of planetary geologic mapping techniques for Mars using terrestrial analogs: The SP Mountain area of the San Francisco Volcanic Field, Arizona              We photogeologically mapped the SP Mountain region of the San Francisco Volcanic Field in northern Arizona, USA to evaluate and improve the fidelity of approaches used in geologic mapping of Mars. This test site, which was previously mapped in the field, is chiefly composed of Late Cenozoic cinder cones, lava flows, and alluvium perched on Permian limestone of the Kaibab Formation. Faulting and foAuthorsKenneth L. Tanaka, James A. Skinner, Larry S. Crumpler, James M. DohmByNatural Hazards Mission Area, Astrogeology Science CenterJanuary 1, 2005                The U.S. Geological Survey, branch of Astrogeology - a chronology of activities from conception through the end of Project Apollo (1960-1973)              No abstract available.AuthorsGerald G. SchaberApril 1, 2001                The San Francisco volcanic field, Arizona              Northern Arizona's San Francisco Volcanic Field, much of which lies within Coconino and Kaibab National Forests, is an area of young volcanoes along the southern margin of the Colorado Plateau. During its 6-million-year history, this field has produced more than 600 volcanoes. Their activity has created a topographically varied landscape with forests that extend from the Pi?on-Juniper up to the BrAuthorsS. S. Priest, W. A. Duffield, Karen Malis-Clark, J. W. Hendley, P.H. StaufferAugust 7, 1974                Guidebook to the geology of Meteor Crater, Arizona              No abstract available.AuthorsEugene Merle Shoemaker, Susan W. Kieffer, Robert L. SuttonJanuary 1, 1967                Cinder Lake crater field location test              When the Apollo astronauts land on the Moon, their precise location will not be known. The real-time geologic mapping planned for the first mission could best be done if the exact position of the landing site were determined. The astronauts may have to find their position, with or without assistance from the Earth-based scientific mission center, before leaving the Lunar Module (LM), and the lessAuthorsNorman G. BaileyJanuary 1, 1959                Impact mechanics at Meteor Crater, Arizona              Meteor Crator is a bowl-shaped depression encompassed by a rim composed chiefly of debris stacked in layers of different composition. Original bedrock stratigraphy is preserved, inverted, in the debris. The debris rests on older disturbed strata, which are turned up at moderate to steep angles in the wall of the crater and are locally overturned near the contact with the debris. These features ofAuthorsEugene Merle Shoemaker 
                  - Data and More  LabelFebruary 17, 2023                Meteor Crater, Northern Arizona: Drill Hole Sample Collection, 1970-1973, and Curation, 2010-2013              Meteor Crater, located in northern Arizona, is one of the best preserved and easily accessible impact sites on Earth. Scientific investigations of this crater have led to improvements in our understanding of impact mechanics, cratering dynamics, and ejecta distribution [e.g., 1-5]. In addition, this site has a rich history as a terrestrial analog that has been used for training astronauts, scientiByAstrogeology Science CenterOctober 15, 2020                Grand Falls, Arizona: Dune Field Sand Transport 2017 - 2019              As part of a NASA-funded study of sediment flux rates at a Mars analog site, we installed a suite of instruments in a small dune field near Grand Falls, Arizona. Data released in this report was collected from 02/07/2017 to 05/22/2019. The Grand Falls (GF) dune field is located on the Navajo Nation. It lies ~70 km NE of Flagstaff, AZ, 2 km east of Grand Falls, and just north of the Little ColoradoByAstrogeology Science CenterOctober 15, 2020                Grand Falls, Arizona: Dune Field Sand Transport 2013 - 2016              As part of a NASA-funded study of sediment flux rates at a Mars analog site, we installed a suite of instruments in a small dune field near Grand Falls, Arizona. Data released in this report were collected from 10/28/2013 to 11/04/2016. The Grand Falls (GF) dune field is located on the Navajo Nation. It lies ~70 km NE of Flagstaff, AZ, 2 km east of Grand Falls, and just north of the Little ColoradByAstrogeology Science Center 
                  - Maps  LabelJanuary 1, 1987                Geologic map of the SP Mountain part of the San Francisco Volcanic Field, north-central Arizona              No abstract available.BySan Francisco Volcanic Field 
                  - News  LabelFrom Earth to Space:  Astrogeology team tell Denver7 News how they use Terrestrial Analog sites to study our Solar System!December 22, 2022  From Earth to Space:  Astrogeology team tell Denver7 News how they use Terrestrial Analog sites to study our Solar System!
Do you want to know how and why scientists use terrestrial analogs to do research and explore space? Watch this quick video of physical scientist Ryan...
Read Article**A Martian landscape right at homeAugust 16, 2022  A Martian landscape right at home
USGS researchers are studying glacial features in Iceland to help reveal past climates on Mars as part of a larger effort to use terrestrial analogs...
Read Article**A Virtual Field-trip Guide to S P Mountain Just Released by Astrogeology Science Center!September 29, 2021  A Virtual Field-trip Guide to S P Mountain Just Released by Astrogeology Science Center!
If you are interested in volcanology,  you should check out our newly-released virtual S P Mountain Field Guide. S P Mountain is a textbook example of...
Read Article**Local Grand Falls Dunes in the Eyes of Scientific ResearchAugust 9, 2021  Local Grand Falls Dunes in the Eyes of Scientific Research
The Grand Falls Dunes are approximately 2 km from Grand Falls.  USGS scientists are studying the Grand Falls Dunes not only to benefit the people who...
Read Article**The truth about a terrifying lava skylight where only the trained should lurkOctober 4, 2020  The truth about a terrifying lava skylight where only the trained should lurk
A lava skylight is not seen by most people as being particularly scary since it is just an opening in the roof above a lava tube from which the...
Read Article**