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Exploring Mars’

Climate History

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2

Mars

Reconnaissance

Orbiter

ESA Mars Express

(NASA: MARSIS)

Mars Odyssey

2013

Operational

2001 - 2012

MAVEN Aeronomy Orbiter

2016

2018

2020

Curiosity –

Mars Science Laboratory

2020

Science Rover

2022

ESA Trace Gas Orbiter

(NASA: Electra)

ESA

ExoMars Rover

(NASA: MOMA)

Opportunity –

Mars Exploration

Rover

Current & Future Mars Missions

InSight

Habitable Environments

Seeking Signs of Life

Future

Follow the Water

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Mars missions contribute to key science goals and themes.

Image Source: NASA/JPL-Caltech

Speaker’s Notes: In the first stage of Mars Exploration, NASA missions focused on “following the water” – seeking signs of past or present water on Mars. Water is key to life as we know it. Mar rover Sojourner studied an ancient flood plain. Orbiters (Mars Global Surveyor, Odyssey, and Mars Reconnaissance Orbiter) contributed findings about past water on Mars, current subsurface water-ice, and surface changes that might indicate some short-term active water flows etc. The Phoenix Mars lander was the first to touch water ice on Mars. These missions all began identifying habitable zones, with Mars rover Curiosity sent specifically to understand Gale Crater as a potential past habitable environment – not just with water, but seeking chemicals necessary to life as we know it, including signs of organics – the chemical building blocks of life. MAVEN is a key part of understanding Mars as a potential habitat, given its important role in determining the climate history of Mars – including when and how long Mars might have had an environment more favorable to life in ancient times. While Mars rover Curiosity cannot detect life, it is on the cusp of the next phase of exploration: seeking signs of life. The proposed Mars 2020 rover, based on Curiosity’s design but with different instruments, would take the first steps toward seeking signs of life itself, linking back to early attempts to do so by the Viking landers. The Mars 2020 rovers would seek 5 of 6 types of potential biosignatures, and prepare a cache for future potential sample return to earth, where all 6 potential biosignatures could be tested in Earth-based laboratories, depending on the samples collected and returned. All of the reconnaissance related to the Martian environment – its resources and potential environmental hazards to human health – and critical technology developments also paves the way for eventual human exploration, a long-term national exploration strategy.

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MAVEN studies Mars’ upper atmosphere

and determines how it interacts with our Sun.

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We have learned how Mars lost

most of its atmosphere and water to space,

making today’s Martian climate challenging for life.

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The Martian atmosphere today is very thin,

so surface pressure is very low (1% of Earth’s).

Long-lasting surface water is no longer possible.

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Yet, Mars has abundant evidence for ancient water!�

(outflow channels, deltas, sedimentary and conglomerate rocks, salts, minerals that form in water etc.)

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That means early Mars likely had a dense, thick atmosphere, which helped keep Mars warmer and wetter.

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Early Mars may have even had a global ocean.

Water is necessary for life as we know it, along with

carbon-based and other chemicals life needs to thrive.

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Over 3 billion years ago, simple, microbial life

was on Earth. How about on Mars?

Level of oxygen

In the atmosphere

+ Diversity of Life

IMAGE SOURCE: NASA/JPL-Caltech

Speaker’s Notes: This chart shows that the environment of Mars may have been more similar to that of Earth earlier in its history. On Earth, we find the earliest signs of microbial (single celled) life dating to about 3.5 billion years ago. Could it have existed on Mars? On Earth, multicellular organisms only became possible once there was enough oxygen in the atmosphere. Oxygen likes to bind with other elements, so it takes a lot before there is enough free oxygen in the atmosphere to help support life’s processes. Early microbial communities produced oxygen as a biproduct, thus altering Earth’s environment enough to support higher life forms. That is not true for Mars. So, we would not expect to find “little green men” or signs of other higher level creatures. Any past life on Mars would have been microbial.

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BLASTED INTO SPACE BY A LARGE IMPACT
TRAVELED TO EARTH & LANDED IN ANTARCTICA
SIGNS OF LIFE?

We don’t yet know if early Mars ever had microbial life.

METEORITE FROM MARS:

ALH84001

IMAGE Credit/Source: NASA

Speaker’s Notes: In addition to providing some interesting and controversial features related to life, meteorites provide a record of Mars from ancient times. Ancient atmosphere trapped in bubbles within the meteorite provide an indication of the atmosphere when the rocks were blasted from the surface of Mars and sent hurling into space. The magnetism of a special class of Martian meteorites known as SNCs (shergottite, nakhlite, chassignite) can also indicate the magnetic fields that were present at the time of ejection. ALH84001 is an SNC meteorite.

More info on ALH84001:

--found in Antarctica in 1984

--was likely ejected from Mars about 15 million years ago

--based on chemical analysis, may have formed at a time when Mars had water on its surface; it is the only known Martian meteorite from this period

--carbonates possibly formed when a subsurface body of water slowly evaporated

--carbonate globules thought by some to be microscopic fossils of Martian microbes

--however, they were extremely small – 20-100 nanometers – smaller than any known cellular life

--findings sparked worldwide interest and controversy; some features were later recreated in lab without life as part of the process

--still a mystery, but most agree that one can’t judge by the shape of features alone

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We don’t know exactly how habitable conditions

on Mars changed over time – or how long they lasted.

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OPTION 1: DOWN�Underground or in the rock record?�Yes, but not enough to account for the loss.

CRUST: Carbonate deposits in a Martian meteorite

SUBSURFACE: Water Ice

MAVEN’s Mystery to Solve: �Where Did All of the Water & CO₂ Go?

Image Credits: NASA/JPL-Caltech/University of Arizona (left); LPI/Alan Treiman (right)

Speaker’s Notes:

The Phoenix Mars lander scooped beneath the Martian surface and became the first “to touch” water ice on Mars. Some water in the form of water-ice exists in the Martian subsurface, and has not been lost to space.

Carbonate globules in ALH84001 are the yellow/orange features at center, and are surrounded by lighter material (orthopyroxene) and small dark grains (chromite). Field of view: ~t 0.5 millimeters across. Water that soaked the rock long ago likely deposited the carbonates. Carbonates may be one indicator for how some of the carbon dioxide was removed from the martian atmosphere, trapped, and stored in Martian rocks as opposed to lost to space. Rovers and orbiters have found carbonates in the rock record on Mars. For example, Mars rover “Spirit” found that the “Comanche” outcrop may be up to ¼ carbonates.

Finding carbonate minerals on Mars is also important because they dissolve in acidic water. Their presence means that the past watery conditions were likely more neutral, and thus more favorable to life, if any existed.

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MAVEN’s Mystery to Solve: �Where Did All of the Water & CO₂ Go?

Escaping ions detected

by the Mars Express orbiter

OPTION 2:

UP

Lost to Space

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MAVEN has discovered how the Martian environment

radically changed by studying the solar wind

and other interactions with the Sun.

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The solar wind is

a high-speed stream of

electrons and protons

released from the Sun.

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High-energy photons

(light) stream constantly

from the Sun.

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The Sun’s activity

has an impact

on planets.

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On Earth, we see “northern and southern lights” when the solar wind’s charged particles collide with gases in our atmosphere.

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Earth’s strong magnetic field deflects many solar wind particles, preventing them from slamming into the upper atmosphere

and stripping it away.

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Early in its history, Mars had a strong magnetosphere

that likely protected it more from solar wind.

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Today, Earth’s magnetic field is globally strong and

more uniform, while Mars’ is localized and scattered.

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A magnetosphere emerges when

electrically charged molten material within a planet

churns in convection while the whole system rotates.

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When Mars was only 500 million years old,

Mars cooled and lost its magnetic field,

radically changing the environment.

Any small life forms that may have emerged

likely died or moved underground.

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Maybe Mars simply cooled on its own due to its smaller size, turning off its internal convection cycle and magnetosphere.

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In addition to cooling, in its early days, Mars was still

vulnerable to impacts from asteroids and other bodies.

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We know from studying craters on Mars that

many asteroids bombarded Mars early in its history,

potentially resulting in atmospheric loss.

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As the core and layers of Mars cooled,

its magnetic field began to disappear.

Ancient Global Magnetosphere

Local Remnants of a Magnetosphere

Today, only local

magnetic fields remain.

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As the magnetic field turned off, the solar wind

began stripping Mars of more of its atmosphere.

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Over several hundred million years,

Mars has lost most of its atmosphere.

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It continues to be stripped away today,

but at a much lower rate.

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Without a strong global magnetosphere,

Mars is vulnerable.

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When an ultraviolet photon from the Sun crashes into

a molecule in the Martian atmosphere . . .

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. . . it knocks away an electron,

turning the molecule into an ion.

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When the Sun’s magnetic field

grazes the Martian atmosphere,

ions spin around it and get carried off into space.

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The Sun’s magnetic field also flings ions

right back into the Martian atmosphere.

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Like hitting balls in a game of pool, they slam into

one atom after another, flinging atoms everywhere.

Those ions zoom back into the atmosphere

going over 2 million miles per hour!

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Some are knocked into space (“sputtered”).

Over billions of years, this sputtering

caused a lot of atmospheric loss.

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By measuring the rate of escape to space today,

scientists can infer how Mars’ environment

changed through its ~4.5 billion year history.

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What we have learned from MAVEN has helped us understand

early conditions favorable to life and how long they lasted.

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MAVEN launched on an Atlas V 401 rocket

from Cape Canaveral Air Force Station, Florida,

November 18 on the first day of the mission window. Lightning almost caused a scrubbing. LAUNCH LINK

L

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MAVEN carried with it the names of ~100,000 people,

artwork from children all over the world, and

haiku poetry submitted in an online contest.

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MAVEN is the length of a school bus:

~11 meters (37 feet) long.

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The orbiter weighs

as much as

an SUV loaded

with a family:

2,550 kg

(~5,622 lb)

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During launch, MAVEN

was protected in the rocket’s “nose cone” (its fairing).

Shortly after launch,

the fairing dropped away, making way for MAVEN to be released on its journey through space to Mars.

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For about 10 months after launch,

MAVEN cruised from Earth to Mars.

MAVEN

Cruise

Mars at Launch

Mars at Arrival

Earth

at Launch

Earth

at Arrival

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Mars Orbit Insertion on ~September 21, 2014

captures MAVEN into orbit around Mars.

It took about a month to go from capture to final orbit,

deploying the booms, and testing instruments and the spacecraft’s alignment.

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MAVEN flew in an elliptical orbit above Mars,

measuring all relevant parts of Mars’ upper atmosphere.

CLOSEST TO MARS

(Periapsis: 150 km/93 mi)

FARTHEST FROM MARS

(Apoapsis: 6200 km/3900 mi)

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CLOSEST TO MARS

(Typical Periapsis: 150 km/93 mi)

At MAVEN’s closest approach,

it was 3 times closer to Mars than the

International Space Station is to Earth.

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Five times on its closest approach,

MAVEN performed “deep dips”

into the Martian atmosphere,

coming as close as

125 km (78 mi).

Typical Periapsis

150 km/93 mi

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MAVEN studied the atmosphere just after

“solar maximum,” a time when the sun is most active.

During this time, the Sun’s activity reveals processes

like those billions of years ago when our star was young.

MAVEN Primary Mission

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In addition to understanding atmospheric changes and loss

in general, MAVEN takes measurements

when events such as solar flares occur.

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MAG (2)

SWEA

Articulated Payload Platform: (IUVS/STATIC/NGIMS)

SWIA

SEP

LPW (2)

For making discoveries,

MAVEN science instruments come in 3 packages.

Particles and Fields

Neutral Gas & Ion

Mass Spectrometer

Remote Sensing

6 instruments characterize

the Sun and solar wind.

1 instrument studies global

characteristics of the upper atmosphere & ionosphere.

1 instrument measures

the composition & isotopes

of neutral gases and ions.

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MAVEN Instrument “Glamour Shots”

Solar Wind Electron Analyzer (SWEA)
Solar Wind Ion Analyzer (SWIA)
SupraThermal And Thermal Ion Composition (STATIC)
Solar Energetic Particle (SEP)
Magnetometer (MAG)
Langmuir Probe and Waves (LPW)

Imaging Ultraviolet Spectrometer (IUVS)

8. Neutral Gas and Ion Mass Spectrometer (NGIMS)

Particles and Fields

Remote Sensing

Spectrometer

1

2

3

4

5

6

8

7

http://lasp.colorado.edu/home/maven/files/2012/02/SWEA5_full.jpg

http://lasp.colorado.edu/home/maven/files/2012/02/SWIA5_full.jpg

http://lasp.colorado.edu/home/maven/files/2012/02/STATIC5_full.jpg

http://lasp.colorado.edu/home/maven/files/2011/03/SEP_full.jpg

http://lasp.colorado.edu/home/maven/files/2011/03/MAG_full.jpg

http://lasp.colorado.edu/home/maven/files/2013/04/MAVEN-Remote-Sensing-Package.jpg

http://lasp.colorado.edu/home/maven/files/2013/04/NGIMS_full_integrated.jpg

Particles and Field (P&F) Package

Solar Wind Electron Analyzer (SWEA) – measures solar wind and ionospheric electrons

Solar Wind Ion Analyzer (SWIA) - measures solar wind and magnetosheath ion density and velocity

SupraThermal And Thermal Ion Composition (STATIC) - measures thermal ions to moderate-energy escaping ions

Solar Energetic Particle (SEP) - determines the impact of SEPs on the upper atmosphere

Langmuir Probe and Waves (LPW) - determines ionospheric properties and wave heating of escaping ions and solar extreme ultraviolet (EUV) input to atmosphere

Magnetometer (MAG) - measures interplanetary solar wind and ionospheric magnetic fields Remote Sensing (RS) Package

Imaging Ultraviolet Spectrometer (IUVS) - measures global characteristics of the upper atmosphere and ionosphere

Neutral Gas and Ion Mass Spectrometer (NGIMS) Package

Measures the composition and isotopes of neutral gases and ions

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By scanning low and high in the upper atmosphere,

MAVEN instruments will measure how the composition

of the atmosphere varies with altitude.

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MAVEN compared its measurements with data collected

by the Curiosity rover on the lower atmosphere and also with the Mars 2020, when it arrives February 2021.

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MAVEN and Curiosity measure the amounts of different kinds

of atoms, ions, and isotopes to calculate escape rates.

Hotter, lighter particles escape much faster.

Argon especially helps determine atmospheric loss.

CREDIT/SOURCE: NASA/jPL-Caltech http://photojournal.jpl.nasa.gov/catalog/PIA16818

Speaker’s Notes:

Basics:

--isotopes are heavier versions of an element

--hotter, lighter particles escape faster

--by comparing ratios of lighter and heavier atoms, ions, and isotopes in the atmosphere today, and comparing that with estimated measurements of ratios in ancient times, it is possible to understand how much of each has been lost

Chart Explanation:

--how to figure out how how Mars transformed from a once water-rich planet, more like our own, into today's drier, colder and less-hospitable world.

--before Curiosity, the argon ratio in Martian meteorites was the best measure of how much atmosphere Mars has lost since the planet's wetter, warmer days billions of years ago

--if Mars held onto all of its atmosphere and its original argon, its ratio of the gas would be the same as that of the sun and Jupiter

--those bodies have so much gravity that isotopes can't preferentially escape, so their argon ratio -- which is 5.5 -- represents that of the primordial solar system

--argon makes up only a tiny fraction of the gas lost to space from Mars

--it is special because it's a noble gas

--that means the gas is inert, not reacting with other elements or compounds, and therefore a more straightforward tracer of the history of the Martian atmosphere. --it is the clearest signature of atmospheric loss because it's chemically inert and does not interact or exchange with the Martian surface or the interior.

--this image shows the ratio of the argon isotope argon-36 to the heavier argon isotope argon-38, in various measurements

--the point farthest to the right designates a new (2013) measurement of the ratio in the atmosphere of Mars, made by the quadrupole mass spectrometer in the Sample Analysis at Mars (SAM) suite of instruments in NASA's Curiosity Mars rover

--for comparison, the previous measurement at Mars by the Mars Viking project in 1976 is shown also

--the SAM result is at the lower end of the range of uncertainty of the Viking data, but compares well with ratios of argon istotopes from some Mars meteorites

--the value determined by SAM is significantly lower than the value in the sun, Jupiter and Earth, which implies loss of the lighter isotope compared to the heavier isotope over geologic time.

--the argon isotope fractionation provides clear evidence of the loss of atmosphere from Mars.

--the above is an example of how to determine atmospheric loss;

--to find out how much water specifically has been lost to space, MAVEN can measure amounts of hydrogen and deuterium (heavy version of hydrogen)

-- familiar example: H2O: two atoms of hydrogen joined to an oxygen atom = water molecule

--less often: deuterium substitutes for hydrogen atom

--hydrogen escapes faster and more often because it is lighter than deuterium

--thus, over time, the Martian atmosphere is stripped of more hydrogen vs. deuterium, so the proportion of deuterium rises

--MAVEN can measure the ratio today vs. the original ratio to see how much hydrogen – and thus water – has been lost

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Fixed High Gain Antenna

Electra (behind)

MAVEN communications and power assets

are also key components of the orbiter.

“Gull-Wing” Solar Arrays

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After its primary science mission, MAVEN now supports

current and future Mars landers and rovers (Perseverence and Ingenuity-the helicopter drone)

by relaying data back to Earth.

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Mission Success:

It takes a team of talented people!

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lasp.colorado.edu/maven

www.nasa.gov/maven

Twitter & Facebook: MAVEN2Mars

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QUESTIONS ABOUT MAVEN?