Looking for Life On Mars

Professor Andrew Coates Wednesday, 23 September 2020

The Rosalind Franklin PanCam team

Mullard Space Science Laboratory, University College London

https://www.gresham.ac.uk/

Mars has changed since it formed 4.6 billion years ago. When life started on Earth ~4 billion years ago, Mars was habitable too, with volcanism, a magnetic field, surface water and a thick atmosphere. Today, Mars is cold and dry, with a thin atmosphere and harsh surface.

In this lecture Professor Andrew Coates discussed the search for life beyond Earth on our closest target, using the Rosalind Franklin rover.

Professor Andrew Coates

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Andrew is Professor of Physics in the Department of Space and Climate Physics at University College London. He is active in space and science outreach, and is currently a vice President of the Society for Popular Astronomy. Credit: M. de la Nougerede, UCL/MSSL 2018

https://www.crowdcast.io/e/gresham-mars

https://s3-eu-west-1.amazonaws.com/content.gresham.ac.uk/data/binary/3339/2020-09-23_AndrewCoates_LifeonMars-T.pdf

https://s3-eu-west-1.amazonaws.com/content.gresham.ac.uk/data/binary/3340/2020-09-23_AndrewCoates_LifeonMars-PP.pdf

The following are notes from the on-line lecture. Even though I could stop the video and go back over things there are likely to be mistakes because I haven’t heard things correctly or not understood them. I hope Professor Coates and my readers will forgive any mistakes and let me know what I got wrong.

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https://www.ucl.ac.uk/mssl/people/prof-andrew-coates

https://twitter.com/planetandrewc?lang=en

Are there other places in our Solar System, besides the Earth, where there was or could have life?

Mars

https://en.wikipedia.org/wiki/Mars

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Its radius is 3390km (half the size of the Earth)

https://en.wikipedia.org/wiki/Exploration_of_Mars#Timeline_of_Mars_exploration

Europa

https://en.wikipedia.org/wiki/Europa_(moon)

Europa or Jupiter II, is the smallest of the four Galilean moons orbiting Jupiter, and the sixth-closest to the planet of all the 79 known moons of Jupiter. It is also the sixth-largest moon in the Solar System. Its radius is 1561km (quarter the size of the Earth)

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https://en.wikipedia.org/wiki/Europa_(moon)#Exploration

In 2012, Jupiter Icy Moon Explorer (JUICE) was selected by the European Space Agency (ESA) as a planned mission. That mission includes 2 flybys of Europa, but is more focused on Ganymede.

Europa Clipper – In July 2013 an updated concept for a flyby Europa mission called Europa Clipper was presented by the Jet Propulsion Laboratory (JPL) and the Applied Physics Laboratory (APL). In May 2015, NASA announced that it had accepted development of the Europa Clipper mission, and revealed the instruments it will use. The aim of Europa Clipper is to explore Europa in order to investigate its habitability, and to aid selecting sites for a future lander. The Europa Clipper would not orbit Europa, but instead orbit Jupiter and conduct 45 low-altitude flybys of Europa during its envisioned mission. The probe would carry an ice-penetrating radar, short-wave infrared spectrometer, topographical imager, and an ion- and neutral-mass spectrometer.

Europa Lander (NASA) is a recent concept mission under study. 2018 research suggests Europa may be covered in tall, jagged ice spikes, presenting a problem for any potential landing on its surface.

Enceladus

https://en.wikipedia.org/wiki/Enceladus

Enceladus is the sixth-largest moon of Saturn. It is about 252 kilometres in diameter (1/25 times the size of the Earth), about a tenth of that of Saturn’s largest moon, Titan. Enceladus is mostly covered by fresh, clean ice, making it one of the most reflective bodies of the Solar System. Consequently, its surface temperature at noon only reaches −198 °C, far colder than a light-absorbing body would be. Despite its small size, Enceladus has a wide range of surface features, ranging from old, heavily cratered regions to young, tectonically deformed terrains.

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This enhanced-colour image of Enceladus by NASA’s Cassini spacecraft features the bluish “tiger stripe” fractures near the Saturn moon’s south polar region. (Image: © NASA/JPL/Space Science Institute)

https://en.wikipedia.org/wiki/Enceladus#Exploration

The answers to many mysteries of Enceladus had to wait until the arrival of the Cassini spacecraft on July 1, 2004, when it entered orbit around Saturn. The programme yielded significant information concerning Enceladus’s surface, as well as the discovery of water vapour with traces of simple hydrocarbons venting from the geologically active south polar region.

Cassini indicated that there was sub-surface salty water.

https://en.wikipedia.org/wiki/Cassini%E2%80%93Huygens

Titan

https://en.wikipedia.org/wiki/Titan_(moon)

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Titan is the largest moon of Saturn and the second-largest natural satellite in the Solar System. It is the only moon known to have a dense atmosphere, and the only known body in space, other than Earth, where clear evidence of stable bodies of surface liquid has been found. Prebiotic molecules have been found.

Its radius is 2575km (1/2.5 times that of the Earth)

https://en.wikipedia.org/wiki/Titan_(moon)#Observation_and_exploration

Huygens was an atmospheric probe that touched down on Titan on January 14, 2005, discovering that many of its surface features seem to have been formed by fluids at some point in the past. Titan is the most distant body from Earth to have a space probe land on its surface.

https://en.wikipedia.org/wiki/Huygens_(spacecraft)

Venus

https://en.wikipedia.org/wiki/Venus

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Venus is the second planet from the Sun. With a rotation period of 243 Earth days, it takes longer to rotate about its axis than any other planet in the Solar System and does so in the opposite direction to all but Uranus (meaning the Sun rises in the west and sets in the east). Venus does not have any moons, a distinction it shares only with Mercury among planets in the Solar System.

It has a radius of 6052 km (95% of the Earth’s radius)

The possibility of life on Venus has long been a topic of speculation, and in recent years has received active research. Following a 2019 observation that the light absorbance of the upper cloud layers was consistent with the presence of microorganisms, a September 2020 article in Nature Astronomy announced the detection of phosphine gas, a biomarker, in concentrations higher than can be explained by any known abiotic source.

https://en.wikipedia.org/wiki/Observations_and_explorations_of_Venus

Mars in the past

3.8 million years ago Mars looked very different to what it looks like now. It had water on its surface. There is indirect evidence of outflow channels.

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More direct evidence came from the Viking Missions

https://en.wikipedia.org/wiki/Viking_program

The Viking program consisted of a pair of American space probes sent to Mars, Viking 1 and Viking 2. Each spacecraft was composed of two main parts: an orbiter designed to photograph the surface of Mars from orbit, and a lander designed to study the planet from the surface. The orbiters also served as communication relays for the landers once they touched down.

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Artist impression of a Viking orbiter releasing a lander descent capsule

https://en.wikipedia.org/wiki/Viking_program#Main_findings

By discovering many geological forms that are typically formed from large amounts of water, the images from the orbiters caused a revolution in our ideas about water on Mars. Huge river valleys were found in many areas. They showed that floods of water broke through dams, carved deep valleys, eroded grooves into bedrock, and travelled thousands of kilometres. Large areas in the southern hemisphere contained branched stream networks, suggesting that rain once fell. The flanks of some volcanoes are believed to have been exposed to rainfall because they resemble those caused on Hawaiian volcanoes. Many craters look as if the impactor fell into mud. When they were formed, ice in the soil may have melted, turned the ground into mud, then flowed across the surface. Normally, material from an impact goes up, then down. It does not flow across the surface, going around obstacles, as it does on some Martian craters. Regions, called “Chaotic Terrain,” seemed to have quickly lost great volumes of water, causing large channels to be formed. The amount of water involved was estimated to ten thousand times the flow of the Mississippi River. Underground volcanism may have melted frozen ice; the water then flowed away and the ground collapsed to leave chaotic terrain.

https://en.wikipedia.org/wiki/Mars_Global_Surveyor

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Artist’s conception of Mars Global Surveyor

Mars Global Surveyor (MGS) was an American robotic spacecraft developed by NASA’s Jet Propulsion Laboratory and launched November 1996. Mars Global Surveyor was a global mapping mission that examined the entire planet, from the ionosphere down through the atmosphere to the surface. As part of the larger Mars Exploration Program, Mars Global Surveyor performed monitoring relay for sister orbiters during aerobraking, and it helped Mars rovers and lander missions by identifying potential landing sites and relaying surface telemetry.

It achieved the following science objectives during its primary mission:

Characterize the surface features and geological processes on Mars.

Determine the composition, distribution and physical properties of surface minerals, rocks and ice.

Determine the global topography, planet shape, and gravitational field.

Establish the nature of the magnetic field and map the crustal remnant field.

Monitor global weather and the thermal structure of the atmosphere.

Study interactions between Mars’ surface and the atmosphere by monitoring surface features, polar caps that expand and recede, the polar energy balance, and dust and clouds as they migrate over a seasonal cycle.

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https://www.sciencemag.org/news/2009/04/did-marss-magnetic-field-die-whimper-or-bang

https://www.space.dtu.dk/english/Research/Universe_and_Solar_System/magnetic_field

Unlike the Earth, Mars has no inner dynamo to create a major global magnetic field. This, however, does not mean that Mars does not have a magnetosphere; simply that it is less extensive than that of the Earth.

The magnetosphere of Mars is far simpler and less extensive than that of the Earth. A magnetosphere is a kind of shield that prevents charged particles from reaching the planet surface. Since the particles borne by the solar wind through the Solar System are typically electrically charged, the magnetosphere acts as a protective shield against the solar wind.

The ionosphere of Mars is not exactly the same as that of the Earth, and there is therefore some disagreement as to which term to use, but simply put it is understood to mean the outer region of the planet’s atmosphere.

Despite the fact that Mars no longer has an internal dynamo capable of generating a large global magnetic field as on Earth, there is evidence to suggest that Mars may once have had such a dynamo. This is mainly supported by observations from the American satellite mission MGS (Mars Global Surveyor), which from 1997 to 2006 measured the magnetic field of Mars using a small magnetometer from an altitude of 100-400 km above the planet’s surface. These measurements showed the existence of powerful magnetic crustal fields on the planet’s surface, far more powerful than those found on Earth.

Giant asteroids may have wiped out Mars’s magnetic field. The energy released by massive collisions upset the heat flow in the planet’s iron core that produced the magnetism, according to a new study. The finding offers a solution to the mystery of the disappearing magnetic field and sheds light on early Earth conditions.

A planet’s magnetic field results from a process called convection. Within the core, molten iron rises, cools, and sinks. The convection induces a magnetic field, in a system known as a dynamo.

The presence of these crustal fields gives rise to local mini-magnetospheres, i.e. small areas where the lines of the magnetic field locally protect the planet surface from electrically charged particles. Mini-magnetospheres occur when a magnetic field line is connected to two different points on the Martian surface, thus creating a kind of bubble. Between these ‘bubbles’, one end of the magnetic field lines can be connected to the planet and the other to the interplanetary magnetic field (IMF).

Like Earth, early Mars had a magnetic field and perhaps an atmosphere conducive to liquid water. But magnetic analysis of the Martian surface indicates that when Mars was a mere 500 million years old, its magnetic field withered away. Without this shield, streams of ionizing particles spewing from the sun strip away a planet’s atmosphere, killing any life that may have emerged or forcing it underground.

The disappearance of the Martian magnetic dynamo has puzzled scientists. One theory links it to the Late Heavy Bombardment, a period of 100 million years when asteroids–some hundreds of kilometres across–smashed into Mars and the inner planets. A massive collision could warm Mars’s mantle, disrupting core convection. That’s because the cooling action of the mantle draws heat from the core, keeping it churning. Without that flow, core convection grinds to a halt.

The theory fits with the observation that only the oldest impact craters on Mars are magnetized. Still, all remained speculation until data came back from the Mars Global Surveyor and other recent spacecraft. Last year, planetary scientists Robert Lillis and Michael Manga, both of the University of California, Berkeley, linked age estimates of impact basins with magnetic field strength to show that the previously established date of heavy bombardment, about 3.9 billion years ago, corresponds to the death of Mars’s dynamo.

Not all scientists are on board with the analysis. David Stevenson, a planetary scientist at the California Institute of Technology in Pasadena, suggests that although the explanation is plausible, he’s not convinced the collisions released enough energy. Furthermore, “the dynamo does not need to have an external influence to stop functioning,” he points out, adding that without enough core convection, “it may simply die of its own accord.”

Mars has volcanism – Olympus Mons

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Viking 1 orbiter view of Olympus Mons with its summit caldera, escarpment, and aureole

https://en.wikipedia.org/wiki/Olympus_Mons

Olympus Mons is a very large shield volcano on the planet Mars. The volcano has a height of over 21 km as measured by the Mars Orbiter Laser Altimeter (MOLA). Olympus Mons is about two and a half times Mount Everest’s height above sea level. It is one of the largest volcanoes, the tallest planetary mountain, and the second tallest mountain currently discovered in the Solar System,

Mars now

Volcanoes are now extinct

There is no large-scale magnetic field, only remnant regions

7 mbar atmospheric pressure,

CO2-rich atmosphere

Cold and dry. The highest temperature is around 10oC and the lowest between -110 and –120oC

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How do we know Mars had water?

https://en.wikipedia.org/wiki/Opportunity_(rover)

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An artist’s portrayal of Opportunity on the surface of Mars.

Opportunity, also known as MER-B (Mars Exploration Rover – B) or MER-1, and nicknamed “Oppy”, is a robotic rover that was active on Mars from 2004 until the middle of 2018. Launched on July 7, 2003, as part of NASA’s Mars Exploration Rover program, it landed in Meridiani Planum on January 25, 2004, three weeks after its twin Spirit (MER-A) touched down on the other side of the planet. With a planned 90-sol duration of activity (slightly less than 92.5 Earth days), Spirit functioned until it got stuck in 2009 and ceased communications in 2010, while Opportunity was able to stay operational for 5111 sols after landing, maintaining its power and key systems through continual recharging of its batteries using solar power, and hibernating during events such as dust storms to save power. This careful operation allowed Opportunity to exceed its operating plan by 14 years, 46 days (in Earth time), 55 times its designed lifespan. By June 10, 2018, when it last contacted NASA, the rover had travelled a distance of 45.16 kilometres

https://en.wikipedia.org/wiki/Scientific_information_from_the_Mars_Exploration_Rover_mission

Opportunity has provided substantial evidence in support of the mission’s primary scientific goals: to search for and characterize a wide range of rocks and regolith that hold clues to past water activity on Mars. In addition to investigating the water, Opportunity has also obtained astronomical observations and atmospheric data.

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It landed in a crater where the rocks were sedimentary. Sedimentary rocks are evidence that something flowed to carry the sediments,

https://www.astrobio.net/album/mars-curiosity-rover/

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An oblique view of Gale Crater, which was the Curiosity rover’s landing site. The image combines data taken by the European Space Agency’s Mars Express spacecraft, as well as NASA’s Viking and Mars Reconnaissance Orbiter missions. At the centre of the crater, which formed about 3.5 billion years ago, is the towering Mount Sharp. Curiosity’s landing site is on the smooth-looking plains inside the crater, near the bottom of the picture. Image credit: NASA/JPL–Caltech/ESA/DLR/FU Berlin/MSSS.

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Annotated elevation map of Opportunity landing site and some surrounding craters including Endeavour and Airy

https://en.wikipedia.org/wiki/Mineralogy_of_Mars

The mineralogy of Mars is the chemical composition of rocks and soil that encompass the surface of Mars. Various orbital crafts have used spectroscopic methods to identify the signature of some minerals. The planetary landers performed concrete chemical analysis of the soil in rocks to further identify and confirm the presence of other minerals. The only samples of Martian rocks that are on Earth are in the form of meteorites. The elemental and atmospheric composition along with planetary conditions is essential in knowing what minerals can be formed from these base parts.

Two earlier missions to Mars carried previous versions of the Alpha Particle X-Ray Spectrometer. The first was the Alpha Proton X-Ray Spectrometer, launched to Mars on the Pathfinder mission in late 1996. The second was the APXS instrument, on board both the Mars Exploration Rovers that arrived on the red planet in January, 2004.

https://mars.nasa.gov/msl/spacecraft/instruments/apxs/

The Alpha Particle X-Ray Spectrometer measured the abundance of chemical elements in Mar’s rocks and soils. Materials were exposed o alpha particles and X-rays emitted during the radioactive decay of the element curium.

http://instructor.physics.lsa.umich.edu/adv-labs/X-Ray_Spectroscopy/x_ray_spectroscopy_v2.pdf

https://www.astrobio.net/mars/evidence-of-water-found-on-mars/

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These plots, or spectra, show that a rock dubbed “McKittrick” near the Mars Exploration Rover Opportunity’s landing site at Meridiani Planum, Mars, has higher concentrations of sulfur and bromine than a nearby patch of soil nicknamed “Tarmac.” These data were taken by Opportunity’s alpha particle X-ray spectrometer, which uses curium-244 to assess the elemental composition of rocks and soil. Only portions of the targets’ full spectra are shown to highlight the significant differences in elemental concentrations between “McKittrick” and “Tarmac.” Intensities are plotted on a logarithmic scale. A nearby rock named Guadalupe similarly has extremely high concentrations of sulfur, but very little bromine. This “element fractionation” typically occurs when a watery brine slowly evaporates and various salt compounds are precipitated in sequence. Credit: NASA/JPL/Cornell/Max Planck Institute

https://photojournal.jpl.nasa.gov/catalog/PIA05470

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This spectrum, taken by the Mars Exploration Rover Opportunity’s Moessbauer spectrometer, shows the presence of an iron-bearing mineral called jarosite in the collection of rocks dubbed “El Capitan.” “El Capitan” is located within the rock outcrop that lines the inner edge of the small crater where Opportunity landed. The pair of yellow peaks specifically indicates a jarosite phase, which contains water in the form of hydroxyl as a part of its structure. These data suggest water-driven processes exist on Mars. Three other phases are also identified in this spectrum: a magnetic phase (blue), attributed to an iron-oxide mineral; a silicate phase (green), indicative of minerals containing double-ionized iron (Fe 2+); and a third phase (red) of minerals with triple-ionized iron (Fe 3+). Image Credit: NASA/JPL/University of Mainz

The Mössbauer spectrometer uses two pieces of radioactive cobalt-57, each about the size of pencil erasers, to determine with a high degree of accuracy the composition and abundance of iron-bearing minerals in martian rocks and soil. It is located on the rover’s instrument deployment device, or “arm.”

https://www.mossbauer.info/currenttopic.html

https://en.wikipedia.org/wiki/Jarosite

Jarosite is a basic hydrous sulfate of potassium and iron with a chemical formula of KFe3+3(OH)6(SO4)2. This sulfate mineral is formed in ore deposits by the oxidation of iron sulfides. Jarosite is often produced as a byproduct during the purification and refining of zinc and is also commonly associated with acid mine drainage and acid sulfate soil environments.

https://en.wikipedia.org/wiki/Jarosite#Mars_exploration

Ferric sulfate and jarosite have been detected by three martian rovers Curiosity, Spirit and Opportunity. These substances are indicative of strongly oxidizing conditions prevailing at the surface of Mars.

NASA Phoenix, 2008

https://en.wikipedia.org/wiki/Phoenix_(spacecraft)

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Phoenix was a robotic spacecraft that landed on Mars on May 25, 2008 and operated until November 2. Its instruments were used to assess the local habitability and to research the history of water on Mars. The mission was part of the Mars Scout Program.

The mission had two goals. One was to study the geological history of water, the key to unlocking the story of past climate change. The second was to evaluate past or potential planetary habitability in the ice-soil boundary.

https://en.wikipedia.org/wiki/Phoenix_(spacecraft)#Results_of_the_mission

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https://apod.nasa.gov/apod/ap080615.html

Phoenix Digs for Clues on Mars. Credit: Phoenix Mission Team, NASA, JPL-Caltech, U. Arizona, Texas A&M University

https://www.jpl.nasa.gov/spaceimages/details.php?id=PIA10911

Below shows what the dig showed up

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This colour image was acquired by the Surface Stereo Imager on NASA’s Phoenix Mars Lander on the 25th day of the mission, or Sol 24 (June 19, 2008).

The trench, called “Dodo-Goldilocks,” is lacking lumps of ice seen previously in the lower left corner. The ice sublimated, a process similar to evaporation, over the course of four days.

In the lower left corner of the image a group of lumps is visible. In the right images, the lumps have disappeared.

https://mars.nasa.gov/odyssey/mission/overview/

https://mars.nasa.gov/odyssey/mission/instruments/grs/

By measuring neutrons, it is possible to calculate the abundance of hydrogen on Mars, thus inferring the presence of water. The neutron detectors are sensitive to concentrations of hydrogen in the upper meter of the surface. Like a virtual shovel “digging into” the surface, the spectrometer allows scientists to peer into this shallow subsurface of Mars and measures the amount of hydrogen that exists there. Since hydrogen is most likely present in the form of water ice, the spectrometer is able to measure directly the amount of permanent ground ice and how it changes with the seasons.

Evidence for ancient lake and stream deposits – conditions for microbial life NASA Curiosity – Grotzinger +, 2014

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https://www.nasa.gov/press/2014/december/nasa-s-curiosity-rover-finds-clues-to-how-water-helped-shape-martian-landscape

Evidence for an ancient lake

https://www.spaceflightinsider.com/missions/curiosity-rover-confirms-ancient-martian-lake/

Estimated size and shape of the former lake inside Gale crater. There may have been others as well. The arrows indicate the direction of the alluvial fan which emptied into the crater from the stream cutting through the crater wall. Image Credit: NASA/JPL-Caltech/MSSS. The lake was believed to be 75km wide with a pH suitable for microbial life.

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Mars express

https://en.wikipedia.org/wiki/Mars_Express

Mars Express is a space exploration mission being conducted by the European Space Agency (ESA). The Mars Express mission is exploring the planet Mars, and is the first planetary mission attempted by the agency. “Express” originally referred to the speed and efficiency with which the spacecraft was designed and built. However, “Express” also describes the spacecraft’s relatively short interplanetary voyage, a result of being launched when the orbits of Earth and Mars brought them closer than they had been in about 60,000 years.

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CG image of Mars Express

It found water under Mars’ south pole. Blue patches indicated an underground lake. There was also water permafrost

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Context map: NASA/Viking; THEMIS background: NASA/JPL-Caltech/Arizona State University; MARSIS

data: ESA/NASA/JPL/ASI/Univ. Rome; R. Orosei et al 2018

Solar wind interaction

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https://sci.esa.int/documents/33745/35957/1567258854092-Weihai-084-Coates-solarwind.pdf

Some water was blown away from the surface of Mars by the solar wind.

https://en.wikipedia.org/wiki/Solar_wind

The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between 0.5 and 10 keV. The composition of the solar wind plasma also includes a mixture of materials found in the solar plasma: trace amounts of heavy ions and atomic nuclei C, N, O, Ne, Mg, Si, S, and Fe. There are also rarer traces of some other nuclei and isotopes such as P, Ti, Cr, Ni, Fe 54 and 56, and Ni 58,60,62. Embedded within the solar-wind plasma is the interplanetary magnetic field. The solar wind varies in density, temperature and speed over time and over solar latitude and longitude. Its particles can escape the Sun’s gravity because of their high energy resulting from the high temperature of the corona, which in turn is a result of the coronal magnetic field.

For those planets lucky to have them, magnetic fields protect against solar winds and cosmic radiation. The outward signs this is happening are auroras.

https://en.wikipedia.org/wiki/Aurora

An aurora (plural: auroras or aurorae), sometimes referred to as polar lights (aurora polaris), northern lights (aurora borealis), or southern lights (aurora australis), is a natural light display in the Earth’s sky, predominantly seen in high-latitude regions (around the Arctic and Antarctic).

Auroras are the result of disturbances in the magnetosphere caused by solar wind. These disturbances are sometimes strong enough to alter the trajectories of charged particles in both solar wind and magnetospheric plasma. These particles, mainly electrons and protons, precipitate into the upper atmosphere (thermosphere/exosphere).

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Artist’s impression of the solar wind pulling away Mars atmosphere: increased loss during solar activity MAVEN mission, Science & Geophys. Res. Letters 2015

Mars’ magnetic field disappeared 3.8 million years ago

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Mars used to be very Earth-like, maybe habitable?

So was there life on Mars? Maybe, when Mars was warmer and wetter, 3.8 billion years ago Many now find evidence from meteorite ALH84001 (announced in 1996) unconvincing. Must go to Mars to find out!

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https://en.wikipedia.org/wiki/Allan_Hills_84001

ALH84001 is a fragment of a Martian meteorite that was found in the Allan Hills in Antarctica on December 27, 1984, by a team of American meteorite hunters from the ANSMET project. Like other members of the shergottite–nakhlite–chassignite (SNC) group of meteorites, ALH84001 is thought to have originated on Mars. However, it does not fit into any of the previously discovered SNC groups. Its mass upon discovery was 1.93 kilograms

Electron microscopy (above right) revealed chain structures resembling living organisms in meteorite fragment ALH84001. It is now believed that it was actual terrestrial contamination.

ESA Mars Express, orbit 28 Jan 04

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Requirements for life

Liquid water

Essential elements (C, H, N, O, P, S)

Source of heat

Time

https://en.wikipedia.org/wiki/Beagle_2

The Beagle 2 was an inoperative British Mars lander that was transported by the European Space Agency’s 2003 Mars Express mission. It was intended for an astrobiology mission that would have looked for past life on, and down to 1.5 metres under, the surface of Mars. It very nearly worked.

Methane on Mars!

Mars Express: trace concentrations of methane (11.5 parts per billion – Formisano+ 2004)

Confirms telescope observations (Mumma+, 2004, 2009)

Methane short lived in Mars atmosphere (hundreds of years)

Must be a source now (Geothermal activity? Life?)

Tantalising results

Also seen by Curiosity sporadically (Webster et al., 2013, 2014, 2018)

Oxygen recently detected also (Trainer et al., 2019)

Methane is not always detected. This parallels the discovery of phosphene in Venus’ atmosphere.

Missions to Mars

ESA – Russia Trace gas orbiter (2016)

https://en.wikipedia.org/wiki/Trace_Gas_Orbiter

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The ExoMars Trace Gas Orbiter (TGO or ExoMars Orbiter) is a collaborative project between the European Space Agency (ESA) and Roscosmos that sent an atmospheric research orbiter and the Schiaparelli demonstration lander to Mars in 2016 as part of the European-led ExoMars programme.

The spacecraft took its first photos of the surface of Mars on 15 April 2018. In April 2019, the science team reported their first methane results: TGO had detected no methane whatsoever, even though their data were more sensitive than the methane concentrations found using Curiosity, Mars Express, and ground-based observations

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photo of South pole

Rosalind Franklin (ExoMars) rover (2022)

https://en.wikipedia.org/wiki/Rosalind_Franklin_(rover)

Rosalind Franklin, previously known as the ExoMars rover, is a planned robotic Mars rover, part of the international ExoMars programme led by the European Space Agency and the Russian Roscosmos State Corporation. The mission was scheduled to launch in July 2020, but was postponed to 2022.

NASA

InSight (2018)

https://en.wikipedia.org/wiki/InSight

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Top: Artist’s rendering of the InSight lander

Bottom: Artist’s rendering of the MarCO CubeSats

The Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) mission is a robotic lander designed to study the deep interior of the planet Mars (geophysics).

Perseverence (2020)

https://en.wikipedia.org/wiki/Mars_2020

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Mars 2020 is a Mars rover mission by NASA’s Mars Exploration Program that includes the Perseverance rover and the Ingenuity helicopter drone. It was launched on 30 July 2020 at 11:50 UTC, and will touch down in Jezero crater on Mars on 18 February 2021.

Perseverance will investigate an astrobiologically relevant ancient environment on Mars and investigate its surface geological processes and history, including the assessment of its past habitability, the possibility of past life on Mars, and the potential for preservation of biosignatures within accessible geological materials. It will cache sample containers along its route for retrieval by a potential future Mars sample-return mission.

UAE

Hope orbiter (2020)

https://en.wikipedia.org/wiki/Emirates_Mars_Mission

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Artists’ impression of the Hope spacecraft

The Emirates Mars Mission is a United Arab Emirates Space Agency uncrewed space exploration mission to Mars. The Hope orbiter was launched on 19 July 2020 at 21:58:14 UTC.

The space probe will study daily and seasonal weather cycles, weather events in the lower atmosphere such as dust storms, and how the weather varies in different regions of the planet. It will also attempt to find out why it is losing hydrogen and oxygen into space and other possible reasons behind its drastic climate changes. The mission is being carried out by a team of Emirati engineers in collaboration with foreign research institutions, and is a contribution towards a knowledge-based economy in the UAE. Hope is scheduled to reach Mars in February 2021.

China

Tianwen-1 orbiter, rover (2020)

https://en.wikipedia.org/wiki/Tianwen-1

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Tianwen-1 undergoing tests in 2019. The silver capsule on top houses the lander and rover, and the gold bottom half with the rocket engine is the orbiter

Tianwen-1 (TW-1) (tentatively Huoxing-1, HX-1 during development) is an interplanetary mission to Mars by the China National Space Administration (CNSA) to send a robotic spacecraft, which consists of an orbiter, a lander and a rover. The mission was successfully launched from the Wenchang Spacecraft Launch Site on 23 July 2020 with a Long March 5 heavy-lift rocket, and is currently en route to Mars.

The aims of the mission may include the following: find evidence for current and past life, produce Martian surface maps, characterize Martian soil composition and water ice distribution, examine the Martian atmosphere, and in particular, its ionosphere, among others. Simulated Martian landings have been performed as part of mission preparations by the Beijing Institute of Space Mechanics and Electricity.

The current Mars mission also would serve as a demonstration of technology that will be needed for an anticipated Chinese Mars sample-return mission proposed for the 2030s. There was also a plan that involved using the current mission to cache Martian rock and soil samples for retrieval by the later sample-return mission.

The Rosalind Franklin rover

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https://en.wikipedia.org/wiki/Rosalind_Franklin_(rover)

Rosalind Franklin, previously known as the ExoMars rover, is a planned robotic Mars rover, part of the international ExoMars programme led by the European Space Agency and the Russian Roscosmos State Corporation. The mission was scheduled to launch in July 2020, but was postponed to 2022.

Looking for life on Mars

Launch 21 Sep 2022

Lands 10 June 2023

Drills up to 2m under surface

Context & analytical instruments

Pan Cam

https://en.wikipedia.org/wiki/Pancam

Each Pancam is one of two electronic stereo cameras on Mars Exploration Rovers Spirit and Opportunity. It has a filter wheel assembly that enables it to view different wavelengths of light and the pair of Pancams are mounted beside two NavCams on the MER camera bar assembly.

Wide-angle stereo camera pair

High-resolution camera

Geological context

Rover traverse planning

Atmospheric studies

WAC: 35° FOV, HRC: 5° FOV

ISEM

https://en.wikipedia.org/wiki/Infrared_Spectrometer_for_ExoMars

IR spectrometer on mast

Bulk mineralogy of outcrops

Target selection

λ = 1.15 – 3.3 μm, 1° FOV

Infrared Spectrometer for ExoMars (ISEM) is an infrared spectrometer for remote sensing that is part of the science payload on board the European Space Agency’s Rosalind Franklin rover, tasked to search for biosignatures and biomarkers on Mars.

WISDOM

https://en.wikipedia.org/wiki/WISDOM_(radar)

Ground-penetrating radar

Mapping of subsurface

stratigraphy

3 – 5-m penetration, 2-cm resolution

WISDOM (Water Ice and Subsurface Deposit Observation on Mars) is a ground-penetrating radar that is part of the science payload on board the European Space Agency’s Rosalind Franklin rover, tasked to search for biosignatures and biomarkers on Mars.

ADRON

https://en.wikipedia.org/wiki/ADRON-RM

Passive neutron detector

Mapping of subsurface water

and hydrated minerals

ADRON-RM (Autonomous Detector of Radiation of Neutrons Onboard Rover at Mars) is a neutron spectrometer to search for subsurface water ice and hydrated minerals. This analyser is part of the science payload on board the European Space Agency’s Rosalind Franklin rover, tasked to search for biosignatures and biomarkers on Mars.

CLUPI

https://en.wikipedia.org/wiki/CLUPI

Close-up imager

Geological deposition environment

Microtexture of rocks

Morphological biomarkers

20-μm resolution at 50-cm distance, focus: 20 cm to ∞

CLUPI (Close-UP Imager) is a miniaturized camera system on board the planned European Space Agency Rosalind Franklin rover. CLUPI was designed to acquire high-resolution close-up images in colour of soils, outcrops, rocks, drill fines and drill core samples, as well as and the search for potential biosignature structures and patterns.

Drill + Ma_MISS

https://en.wikipedia.org/wiki/Mars_Multispectral_Imager_for_Subsurface_Studies

IR borehole spectrometer In-situ mineralogy information

λ = 0.4 – 2.2 μm

Mars Multispectral Imager for Subsurface Studies (MA-MISS) is a miniaturized imaging spectrometer designed to provide imaging and spectra by reflectance in the near-infrared (NIR) wavelength region and determine the mineral composition and stratigraphy. The instrument is part of the science payload on board the European Rosalind Franklin rover, tasked to search for biosignatures,

Analytical Laboratory Drawer

https://www.esa.int/ESA_Multimedia/Images/2019/05/ExoMars_Analytical_Laboratory_Drawer

The instruments will make a detailed study of the composition and chemistry of the soil samples collected by the Rover’s drill.

MicrOmega

https://en.wikipedia.org/wiki/MicrOmega-IR

VIS + IR spectrometer

Mineralogy characterisation

of crushed sample material

Pointing for other instruments

λ = 0.9 – 3.5 μm, 256 x 256, 20-μm/pixel, 500 steps

MicrOmega-IR is an infrared hyperspectral microscope that is part of the science payload on board the European Rosalind Franklin rover, tasked to search for biosignatures on Mars. The rover is planned to land on Mars in spring 2023. MicrOmega-IR will analyse in situ the powder material derived from crushed samples collected by the rover’s core drill.

RLS

https://en.wikipedia.org/wiki/Raman_Laser_Spectrometer

Raman spectrometer

Geochemical composition

Detection of organic pigments

spectral shift range 200–3800 cm–1, resolution ≤ 6 cm–1

Raman Laser Spectrometer (RLS) is a miniature Raman spectrometer that is part of the science payload on board the European Space Agency’s Rosalind Franklin rover, tasked to search for biosignatures and biomarkers on Mars.

Raman spectroscopy is sensitive to the composition and structure of any organic compound, making it a powerful tool for the definitive identification and characterisation of biomarkers, and providing direct information of potential biosignatures of past microbial life on Mars. This instrument will also provide general mineralogical information for igneous, metamorphous, and sedimentary processes.

MOMA

https://en.wikipedia.org/wiki/Mars_Organic_Molecule_Analyser

LDMS + Pyr-Dev GCMS

Broad-range organic molecules with high sensitivity (ppb)

Chirality determination

Laser desorption extraction and mass spectroscopy

Pyrolisis extraction in the presence of derivatisation agents, coupled with chiral gas chromatography, and mass spectroscopy

The Mars Organic Molecule Analyser (MOMA) is a mass spectrometer-based instrument on board the Rosalind Franklin rover to be launched in August–October 2022 to Mars on an astrobiology mission. It will search for organic compounds (carbon-containing molecules) in the collected soil samples. By characterizing the molecular structures of detected organics, MOMA can provide insights into potential molecular biosignatures. MOMA will be able to detect organic molecules at concentrations as low as 10 parts-per-billion by weight (ppbw). MOMA examines solid crushed samples exclusively; it does not perform atmospheric analyses.

The Principal Investigator is Fred Goesmann, from the Max Planck Institute for Solar System Research in Germany

https://www.esa.int/ESA_Multimedia/Videos/2020/03/ExoMars_Rosalind_Franklin_rover_3601

https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Exploration/ExoMars/All_instruments_onboard_Rosalind_Franklin_rover

https://www.youtube.com/watch?v=eKTdoHDWm0Q

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Some of PanCam team with rover model at ESTEC, Dec 2019

Parachute test, Oregon, 2019

https://www.esa.int/ESA_Multimedia/Videos/2019/12/ExoMars_parachute_extraction_tests

The parachute is the largest one yet to be sent to Mars

Why Rosalind Franklin?

https://en.wikipedia.org/wiki/Rosalind_Franklin

• Brilliant X-ray crystallographer

• Photograph (Photo 51) of a fibre of DNA

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Photo 51 (above left) Working notes on DNA (above right)

• Critical to Watson and Crick’s discovery of the double helix

• Other important work on structure of carbon, viruses

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Rosalind Elsie Franklin (25 July 1920 – 16 April 1958) was an English chemist and X-ray crystallographer whose work was central to the understanding of the molecular structures of DNA (deoxyribonucleic acid), RNA (ribonucleic acid), viruses, coal, and graphite.[2] Although her works on coal and viruses were appreciated in her lifetime, her contributions to the discovery of the structure of DNA were largely recognised posthumously.

Penetration of Organic Destructive Agents

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ExoMars exobiology strategy:

‣ Identify and study the appropriate type of outcrop;

‣ Collect samples below the degradation horizon and analyse them.

You need to dig down to a depth of about 1.5 to 2m to get good samples.

Rosalind Franklin landing site – Oxia Planum

• Clay bearing rocks 3.9 bya

• Remnants of a fan or delta near the outlet of Coogoon Vallis

HiRISE-scale characterization of the Oxia Planum landing site for the Exomars 2022 Mission

Lots of history of water here.

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A) Locations of OP on (A) Mars and (B) in Arabia Terra. Phyllosilicate detections are in red. Estimated/study landing ellipses are in yellow. -3000 m contour is shown in blue. Fluvial channels and sediment fan remnants are evident. C) Designation of mapping ‘Areas’.

image

PanCam: the science ‘eyes’ of the Rosalind Franklin rover

• Filter wheels (FWs) MSSL

• Two Wide angle cameras (WACs) TAS-CH

• High Resolution Camera (HRC) DLR/OHB

• PanCam Interface Unit (PIU) MSSL

• DC-DC converter (DC-DC) MSSL

• Optical bench (OB) MSSL

• ‘Small Items’: PanCam Calibration

Target (PCT), Fiducial Markers (FidMs), Rover Inspection Mirror (RIM) Aberystwyth

• Stereo, colours, shapes and scales

• Science team

image

image

image

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PanCam’s filters

• 11 on each WAC

• Geology – water -rich minerals • Atmosphere – water vapour

• Colour HRC provides rock texture

image

What the filters would look like on Mars

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Courtesy Patrick Curry, MSSL

https://www.linkedin.com/in/patrick-curry-048a744b/?originalSubdomain=uk

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Courtesy Helen Miles, Aberystwyth

https://www.aber.ac.uk/en/cs/staff-profiles/listing/profile/hem23/

Examples of PanCam use and results

Testing the PanCam and the operators

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5568594/

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Many field tests See Coates+ (2017). Views of AUPE PanCam simulator at tests in a Hertfordshire, UK, quarry (bottom left) and at the AMASE campaign, Svalbard.

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Screenshot of PRo3D showing a geological interpretation session in the Shaler area (Gale Crater, MSL mission), based on PRoViP 3-D reconstruction from a set of 99 MSL Mastcam stereo images. This detailed interpretation of the stratigraphy shows the main stratigraphic boundaries as gray lines, bedset boundaries as thick white lines, and laminations within those bedsets as thin white lines (note that the original image is in color). The dip and strike values are available directly in PRo3D in color coded by dip value and generally dip 15–20° to the southeast (validation forthcoming). The findings are consistent with those in the works of Anderson et al. (2015) and Edgar et al. (2014) in that the outcrop represents a changing fluvial environment, with recessive, fine-grained units interlayered with coarse, pebbly units. Data courtesy of NASA/JPL, image courtesy of Imperial College London, Robert Barnes/Sanjeev Gupta; www.provide-space.eu

https://www.sciencedirect.com/science/article/pii/S0019103515000445

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Principal Component Analysis plots showing the groupings of spectral classes as observed with AUPE-2 R∗ data. Vertical lines divide Fe-oxide bearing targets from high albedo non-Fe oxide targets including gypsum, zeolite, and sulfur. Horizontal lines further define the quadrant for which all gypsum-bearing targets fall within (grey box). Plots include all ROIs from sites A04_Tuff (black), A06_Soils (red), A07_Pillow (green), and A08_Vein (blue). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) Harris+ (Icarus 2015)

MURFI, Utah desert, 2016

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Balme et al., PSS 2019

Trial in the Atacama Desert, Feb 2019

image  image

Courtesy PanCam team

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The process of working out the mineralogy

https://directory.eoportal.org/web/eoportal/satellite-missions/e/exomars

https://www.spacetv.net/exomars-spacecraft/

https://exploration.esa.int/web/mars/-/57231-tas-i-planetary-protection-team

The rover will move with a speed of 3ms-1 and be active for 218 days. It is in Turin at the moment.

PanCam integration at UCL-MSSL

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PanCam

• delivered to Airbus May 2019

• installed August 2019

image

https://www.esa.int/spaceinimages/Images/2019/05/ExoMars_PanCam_filters

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PanCam on the rover

image

image image

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Courtesy Airbus – M.Alexander

‘First light’ on the rover! PanCam image, August 2019

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Courtesy Airbus – M.Alexander ESA/ExoMars/PanCam team

Summary

Rosalind Franklin (ExoMars 2020) will provide an important new dimension on Mars: drill under surface

PanCam, with other context instruments, provides geological and atmospheric context

a.coates@ucl.ac.uk

exploration.esa.int

www.ucl.ac.uk/mssl

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Subjects

Astronomy Science Physics

Questions and answers

1) Phosphine is used as a biocide gas. It is found in the stomach of Badgers and also in Penguine poo !!

https://orbiterchspacenews.blogspot.com/2020/09/russian-spectrometer-did-not-detect.html states that the Trace Gas Orbiter failed to find Phosphine in Mars Atmosphere to 2pbb.

2) Using the Drake equation (or variation) for the likelihood of extra-terrestrial life, what is the probability of two planets in the same stellar system developing life independently?

Professor Coates did not have a definitive answer, saying you can’t determine everything from an equation

3) Why is it indicative that if there is water there is life or possibly life on a planet, e.g. Mars?

Water is a universal solvent, and a solvent is necessary for life’s chemical reactions. That solvent needs to perform an active, diverse, and flexible role. Water is so far the only common liquid we know that is capable of this.

4) What changed the temperature on mars from warm to cold now? Is it the formation of the planet that was creating the warmth?

Mars is smaller than the Earth. During the formation of the Solar System it lost its heat of formation more quickly. Less heat to keep the magnetic field going. Convection in a metallic molten core is necessary to produce the magnetic field. Also, Mars’ thin atmosphere means that there are extremes of temperature. No insulating layer

5) With the lack of a magnetic field on mars, what safety measures would need to be done to allow a manned mission to mars? Could this be done with current technology?

Not at the moment. You could land on a crustal magnetic field site, but it would be difficult to parachute people and materials there.

https://phys.org/news/2017-03-nasa-magnetic-shield-mars-atmosphere.html

6) Would the geothermal activity source of methane be compatible with the fact that Mars’ magnetic field has extinguished? Aren’t both related to a flow of a liquid metal around the core like in the Earth?

Mars has a very small-scale geothermic activity. This is not sufficient to produce a magnetic field

7) What aspects of Mars make the parachute so difficult to engineer?

The thin and low-pressure atmosphere. It is thick enough to cause some heating but not enough to slow down a conventional parachute.

John Murrell wrote: I am no expert but from other presentations the combination of High Speed and a very thin Atmosphere make parachutes difficult. They are release at quite a high Mach number well above the speed of sound (At that height in the Martian Atmosphere).

NASA’s latest Mars Rover: Will Perseverance find life in 2021? | Science with Sam

https://www.youtube.com/watch?v=xId6wkCGfWA&utm_source=NSNEW&utm_campaign=a1a20c0098-NSNEW_170920_COPY_01&utm_medium=email&utm_term=0_e65fab71ff-a1a20c0098-378752823

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