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[Music]

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[Applause]

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hey I'm stat I'm going to talk to you

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today about LC so one of the challenges

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of sampling europa is using the Europa

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Lander cameras to find the spot on the

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surface nearby the lander that contains

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evidence of habitability of the ocean

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and potentially bio signatures to

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measure from somewhere within a 2 square

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meter workspace and do this in just a

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couple of days within the confines of a

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22 day mission now this sounds extremely

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challenging and it will be but we've

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actually done something related before

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and that is finding the Mars 2020

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landing site granted at a much slower

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pace but with a similar objective of

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using a spectral signature of a mineral

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to find a past habitable environment

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that has the potential to preserve bio

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signatures so we can take a lesson from

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how that was done using data from the

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Chris Amon and other instruments on MRO

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looking for carbonates or other minerals

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that with evidence potential landing

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sites in materials to sample this is

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actually the discovery image in which

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carbonates were first identified on Mars

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and you see a three color composite here

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from visible wavelengths from these data

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you can guess at the presence in

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location of carbonates or other minerals

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of interest from color and morphology

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but you can't be sure because the

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diagnostic features are in the infrared

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this is the infrared part of the same

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image using false color and here you can

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directly detect primary mafic minerals

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clays and carbonates because they have

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strong spectral signatures at these

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wavelengths and to give you the answer

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the inset at the right here that bright

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green material that's the carbonate you

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just can't see it at the visible

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wavelengths now the the attributes that

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make a material desirable to measure in

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situ also will address the other science

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goals

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of Europa Lander for example one of the

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indicators of an interesting material

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will be concentrated salts showing that

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you've got ocean water that salt

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chemistry also illuminates the chemistry

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of the ocean and its potential

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habitability and the spectral signatures

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to look for or 1.3 to 2.6 microns the

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ideal material to sample has the least

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radiation damage of the material of the

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site leaving complex organic molecules

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intact and this this signature of that

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could be fresh Amorphis ice or ice that

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has crystallized but not older ice whose

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outer rims have been damaged by

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radiation finding this desirable

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material also is an indication of

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geologically young ice emplacement and

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the spectral signatures of the interior

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and the rims of the grains would be at

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one point six five and 3.1 microns

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finally organic compounds would be the

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indication of a potential biotic

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material and those are evident from

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absorption features at 3.2 to 3.4

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microns now I will try to convince you

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that the Europa Lander should be

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surveying its landing site in its

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workspace in the infrared this iconic

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Galileo false-color visible image shows

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Europa a 1.6 kilometers per pixel and

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this clearly a spectrally heterogeneous

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surface let's zoom down to just the

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three pixel scale in this image and

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you've got the highest resolution

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Galileo image that you've taken and what

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you see is the heterogeneity extends

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down to the smallest resolvable skills

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and the contrasts are even larger if we

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zoom down to one pixel in this image

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that's the Europa Landrus landing site

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and the workspace is within that it may

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very well present a variety of materials

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however I our spectral variations are

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only known a very low resolution not

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like the visible resolution you see here

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and the use of visible color as a proxy

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to find them is really unknown so LC

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addresses these issues by taking landed

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imaging into the infrared

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it actually has three sensors there are

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dual stereo imagers a right eye that

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covers point four to 1.8 microns and the

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left eye that covers point eight to

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three point six microns each eye has a

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15 degree field of view and 375 micro

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Radian pixels twenty spectral filters

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between the two eyes are in four groups

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one group matches the spectral filters

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on the ice imaging system on Europa

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clipper to extrapolate color variation

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CC from orbit to the landing site a

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second group discriminates Isis and

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hydrated salts a third distinguishes

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crystalline and amorphous isip both the

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scales of the grain rims and the green

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interiors and a fourth group of filters

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detects organic materials the third

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sensor is a point spectrometer with a

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two milliradian field of view that

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samples the surface of better than ten

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the inter meters per channel and that

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will characterize any heterogeneity that

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you identify in the images at much

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higher spectral resolution allowing you

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to identify a range of minerals and

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organic compounds this CAD rendering of

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the exterior of the instrument concept

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shows the outer surface that acts as a

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radiator to passively cool the optics in

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the focal plane using the surroundings

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to a working temperature of 115 Kelvin

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and you can note the cyclops design

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where the two eyes are the stereo

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imagers and then that little eye in the

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middle of the forehead is a point

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spectrometer if you take away the

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housing you can see the innards of the

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instrument and fold mirrors bend the

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field of view of both cameras through a

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pair of miniaturized filter wheels on

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both eyes and mirrors reflect the light

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onto a different parts of a single

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detector that is shielded by a radiation

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shield to minimize the noise from the

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radiation and the point spectrometer

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folds its light around the radiation

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shield and uses another unused part of

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the same focal plane array here's the

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optical design of the two eyes

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they're subtly different because of the

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different materials and wavelength

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ranges but each eye has

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adjustable focus so you can focus nearer

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or further and on board a technique

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called Z stacking is performed to create

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a best focused

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merged image this shows a flattened

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version of the optical design of the

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spectrometer it uses what's called an

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off-night design in a small cast green

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telescope and note these little light

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bulb icons a field filling optic in all

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three sensors has a rear surface that is

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partially silvered and will diffusely

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transmitted light from a closed loop

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control calibration source enabling a

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landed radiometric calibration to be

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done on the data that are collected

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here's the block diagram of the

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instrument the sensor containing all

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three sensors is located on the

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high-gain antenna there is motors to

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control the filter wheels in each eye as

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well as the adjustable focus and then

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the data processing unit is located in

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the Landorus radiation vault there are

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three cards a digital card contains

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processors and memory to process data on

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board to squeeze down the data volume an

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interface card communicates with the

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spacecraft and also drives the motors

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the calibration lamps in a heater and

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the third card provides power to

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everything else so this graph shows how

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the spectrometer will detect different

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materials on the surface you see here in

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yellow and light blue Europa IC and na

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nice materials and in green and orange

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mineral analogs to the nice materials

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the black lines are simulated spectra as

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sampled through the points spectrometer

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so they're nearly laboratory quality and

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the region of interest is here around

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1.4 to 1.5 microns and this shows the

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same data resembled into the band passes

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of the cameras the minimum reflectance

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in ice is at one wavelength and the

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minimum reflectance in hydrated salts is

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a different filter so

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it's easy to distinguish concentrated

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salts from the background ice and in

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addition there's a filter of 1.25

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microns that measures the depth of a

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band that's first sensitive dyes grain

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size allowing one to map out differences

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in surface texture at the landing site

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this is a 2.8 to 3.6 micron region again

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Europa materials on the bottom plot

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aromatic and aliphatic organics in pink

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and green primitive meteoritic material

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that contains both in black and in the

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bottom crystalline ice note the ice ax

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is fully crystalline has this pronounced

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reflectance peak at 3.1 microns that's

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lacking in highly radiation damaged ice

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these are those this the right graph is

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those data resampled into the camera ban

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passes which could easily distinguish

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concentrations of organic material as

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well as the currents of crystalline ice

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now the data processing unit is

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essential to the operation of the

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instrument it mitigates the radiation

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noise in the data and helps to control

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the data volume the mitigation of

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radiation noise uses is it a technique

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that's been developed for the maies

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imager on Europa clipper for every frame

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position there's actually multiple

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integrations you throw out a subset of

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the highest values which have the

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radiation noise and you co add the rest

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to improve signal-to-noise to squeeze

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down the data volume for 16 of the 20

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filters we use a technique that we we

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pioneered on chrism called summary

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products where you take many wavelengths

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of light and reduce them down to a few

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parameterised variables that show

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spectral variations these will be

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created on board by calibrating the

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images using the calibration data that

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you've taken rescaling the pixels scale

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of each image to the common stereo

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filter to both eyes and then performing

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band math compressing and down linking

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the summary products the calibrated data

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will reside on board and from the ground

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can be interrogated for the 20 channel

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spectra to provide more detail on

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whatever of interest shows up in the

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summary products and the spectrometer

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can target target regions of interest

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for further information LC is fully

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capable of addressing Europa Landers

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science questions about habitability and

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geology including exogenic and energetic

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materials deposited on the surface

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tectonic features on the surface and

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radiation processing using a series of

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eight different imaging campaigns

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including stereo and change detection

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mosaics of the landing site spectral

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images of the workspace and at different

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nested resolutions and higher quality

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spectral information a coverage of the

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trench as it's dug and the sites of the

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samples that are collected

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so in summary LC merges the traditional

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capabilities of landed imaging system

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high-resolution stereo change detection

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and color mapping with new capabilities

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are enabled by its coverage in the

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shortwave infrared mapping of

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compositions detection and

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discriminating minerals from ice in the

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background detecting organics and

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determining crystal of variations and

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ice crystallinity that point you towards

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the freshest material to collect for

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onboard analysis thank you and I'm happy

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to take any questions

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you have the radiation damage for the

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spacecraft so what that does is most of

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your mission you want to be harvesting

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samples and analyzing them on board so

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it puts the onus on the context cameras

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to find that spot fast and that's why

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the onboard spectral capabilities and

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our word processing minimizes the

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back-and-forth between the ground and

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spacecraft to do that while you've got

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still three weeks of lander life because

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the radiation in as explained by Cynthia

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in the previous presentation because the

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radiation will kill the lander in about

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a month well then it could survive for

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up to three months which is about the

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the radiation lifetime of the lander but

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in terms of getting through the baseline

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mission of three samples we can do that

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in seven days then there's an additional

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seven days of margin and an additional

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seven days on top of that which puts you

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at the twenty two days which is also a

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multiple of three point five five days

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which is Europa's a diurnal cycle around

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Jupiter

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so the 22 days is our nominal mission

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with plenty of margin but then using up

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our mass margin and allocating that to