January 5, 2014

Diviner Maps of the Chang’e 3 Landing Site

The LRO Diviner Lunar Radiometer has been mapping the entire Moon on a nearly continuous basis since July, 2009. The Diviner dataset includes excellent spatial and diurnal coverage of the Mare Imbrium region. The Diviner team has produced maps of the thermal behavior and and a range of derived quantities at Chang’e 3 landing site that are described below.

Brightness temperature (TB):

Brightness temperature is the temperature that a black body (a body with emissivity = 1) in thermal equilibrium with its surroundings would have to be to produce the radiance that Diviner observes in a particular wavelength interval.

All brightness temperatures Diviner has measured in its 7 thermal channels that are within ~400 m of the Chang’e 3 lander, plotted as a function of local time.

All brightness temperatures Diviner has measured in its 7 thermal channels that are within ~400 m of the Chang’e 3 lander, plotted as a function of local time.

Bolometric temperature (TBOL):

Bolometric temperature is the wavelength-integrated radiance in all seven thermal Diviner channels expressed as the temperature of an equivalent blackbody (Paige et al., 2010). Using data from the entire Diviner dataset to date (Jul. 2009 - Dec. 2013), we can calculate the maximum and minimum bolometric temperatures that have been observed at the Chang’e 3 landing site.

Minimum bolometric temperature observed at the Chang’e 3 landing site. The coldest part of the lunar day is the end of the night, just before sunrise. Fresh craters appear warmer because they are more rocky and so retain heat for longer at night. The minimum observed bolometric temperature at the location of the Chang’e 3 lander is 94K.

Minimum bolometric temperature observed at the Chang’e 3 landing site. The coldest part of the lunar day is the end of the night, just before sunrise. Fresh craters appear warmer because they are more rocky and so retain heat for longer at night. The minimum observed bolometric temperature at the location of the Chang’e 3 lander is 94K.

Maximum bolometric temperature observed at the Chang’e 3 landing site. Included data are within 2 hours of local noon, the hottest part of the lunar day. Striping across the map is due to differences in local time coverage. The maximum observed bolometric temperature at the location of the Chang’e 3 lander is 356K.

Maximum bolometric temperature observed at the Chang’e 3 landing site. Included data are within 2 hours of local noon, the hottest part of the lunar day. Striping across the map is due to differences in local time coverage. The maximum observed bolometric temperature at the location of the Chang’e 3 lander is 356K.

Regolith Temperature and Rock Abundance

The maps show Lunar surface rock abundance and nighttime rock free regolith temperatures. These data were derived from LRO Diviner channels 6-8 (wavelengths of 12-100 microns) data. The colorized maps are shaded using the LRO Camera derived digital terrain model.

Bandfield, J.L., R.R. Ghent, A.R. Vasavada, D.A. Paige, S.J. Lawrence, M.S. Robinson (2011) Lunar surface rock abundance and regolith fines temperatures derived from LRO Diviner Radiometer data.  Journal of Geophysical Research, 116, 010.1029/2011JE003866.

Scholten, F., J. Oberst, K.-D. Matz, T. Roatsch, M. Wählisch, E.J. Speyerer, M.S. Robinson (2012) GLD100: The near-global lunar 100 m raster DTM from LROC WAC stereo image data.  Journal of Geophysical Research, 117, 010.1029/2011JE003926.

Diviner nighttime lunar regolith temperatures at the Chang'e 3 landing site. The temperatures are derived from throughout the lunar night and are shown in deviation from the local time average. Elevated temperatures are associated with craters that contain small or shallowly buried rocks beneath a thin regolith cover. Dark blue/purple spots in the region show "cold spots" that have a particularly fluffy and insulating regolith cover.

Diviner nighttime lunar regolith temperatures at the Chang'e 3 landing site. The temperatures are derived from throughout the lunar night and are shown in deviation from the local time average. Elevated temperatures are associated with craters that contain small or shallowly buried rocks beneath a thin regolith cover. Dark blue/purple spots in the region show "cold spots" that have a particularly fluffy and insulating regolith cover.

Diviner lunar rock abundance at the Chang'e 3 landing site. The data are sensitive to rocks larger than about 0.5 m and higher concentrations of smaller rocks are likely present. Most rocky regions are associated with numerous small craters that excavate rocky material from underneath the powdery lunar regolith cover.

Diviner lunar rock abundance at the Chang'e 3 landing site. The data are sensitive to rocks larger than about 0.5 m and higher concentrations of smaller rocks are likely present. Most rocky regions are associated with numerous small craters that excavate rocky material from underneath the powdery lunar regolith cover.

H-parameter Map

Taking into account the different nighttime cooling behavior of rocks and regolith, we use Diviner brightness temperatures to produce maps of rock abundance and nighttime regolith temperature (Bandfield et al., 2011). We then fit thermal models to the regolith temperature data to derive a subsurface profile of thermal conductivity and density (Hayne et al., 2013). The steepness of this profile is described by the “H-parameter”, where small values of H indicate more compact regolith, and large values of H are consistent with more fluffy, unconsolidated regolith. This parameter is similar to thermal inertia, a commonly used quantity in planetary science.

The H-parameter map shows that the Chang'e-3 lander (indicated by the 'X') is located in a region of typical lunar mare regolith. The red "hot spots" (low H values) reveal denser, rocky regolith surrounding many impact craters. Chang'e-3 is located adjacent to one of these craters, and therefore may find the regolith slightly more compact and rocky than average. The diffuse blue feature about 25 km to the southwest of the landing site is a "cold spot" characteristic of extremely fluffy material surrounding a very fresh impact crater. These unusual features are not well understood, but are thought to be a consequence of regolith decompression during the impact process, which gradually fades over time (Bandfield et al., 2014).

The H-parameter map shows that the Chang'e-3 lander (indicated by the 'X') is located in a region of typical lunar mare regolith. The red "hot spots" (low H values) reveal denser, rocky regolith surrounding many impact craters. Chang'e-3 is located adjacent to one of these craters, and therefore may find the regolith slightly more compact and rocky than average. The diffuse blue feature about 25 km to the southwest of the landing site is a "cold spot" characteristic of extremely fluffy material surrounding a very fresh impact crater. These unusual features are not well understood, but are thought to be a consequence of regolith decompression during the impact process, which gradually fades over time (Bandfield et al., 2014).

Diviner Standard Christiansen Feature (CF) Value

Diviner uses three bands near 8 microns (Ch 3, 4, & 5) to measure the Christiansen Feature (CF) and determine the bulk composition of lunar soils (Greenhagen et al., 2010, Science).  The CF is related to silicate polymerization and shifts in a systematic way across lunar compositions (e.g. Conel, 1969, JGR; Logan et al., 1973, JGR; Salisbury and Walter, 1989, JGR).  The median CF Value for highlands materials is 8.15 and mare materials is 8.28.  Standard CF is sensitive to illumination and viewing geometry, and space weathering.

The composition of the area around the landing site is very uniform, and similar to global averages.  Most of the "color" in this map is due to the combination of data observed at different local times and/or caused by small, fresh impact craters, which have CFs shifted to shorted values.

The composition of the area around the landing site is very uniform, and similar to global averages. Most of the "color" in this map is due to the combination of data observed at different local times and/or caused by small, fresh impact craters, which have CFs shifted to shorted values.

Diviner Corrected Christiansen Feature (CF) Value

Due to an observed dependence of Standard CF Value with solar illumination and instrument viewing geometry, we attempt to normalize the radiance data to equatorial noon and calculate a “corrected” CF Value (after Greenhagen et al., 2010, Science; Greenhagen et al., 2011, LPSC).  Corrected CF Values are useful to comparisons across ranges of latitude and local time and for comparisons to laboratory data.  Data artifacts are most noticeable in very dark terrains, which are underrepresented in the photometric database used to compile the correction.

The compositional uniformity of the landing site area is even more apparent with the Corrected CF product than the Standard CF.  The "color" in this map is largely data artifacts and the small fresh impact craters.

The compositional uniformity of the landing site area is even more apparent with the Corrected CF product than the Standard CF. The "color" in this map is largely data artifacts and the small fresh impact craters.

Diviner Concavity Index (CI)

This spectral concavity index was developed to identify compositions that have CFs outside (either short- or long-ward of Diviner’s 8 micron bands (Glotch et al., 2010, Science).  The CI is particularly useful for identifying highly silicic materials such as quart and alkali feldspar, which have a strong positive CI (Glotch et al., 2010, Science).

There is no evidence for highly silicic materials in or around the Chan'ge 3 landing site.

There is no evidence for highly silicic materials in or around the Chan'ge 3 landing site.

Diviner Ch 4 Brightness Temperature (TB)

The peak of the CF is most consistently near Diviner’s Ch 4 passband; therefore, Ch 4 has a TB with close to unit emissivity.

This map shows the average temperatures for the data used to produce the Standard and Corrected CF, and the CI maps.

This map shows the average temperatures for the data used to produce the Standard and Corrected CF, and the CI maps.

change3_tb4_animation

November 20, 2013

Science outreach event a huge success!

On November 17th, the Diviner team participated in UCLA’s largest science outreach event of the year, Exploring Your Universe.  The Diviner exhibit included a hands-on cratering activity with flour and cocoa powder, an infrared camera demo, and an informational display with animations and giveaways.  The event is put on by several science departments and student groups on campus and brought over 4000 participants to campus this year.  A special thanks to Elliot, Pierre, Mark, Michaela, and Szilard for donating their time to increasing public awareness about lunar science!

Check out images of the Diviner booth below!

September 6, 2013

Tune in for live webcast of LADEE Moon mission launch

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Diviner PI David Paige will join Bill Nye (the Science Guy) to provide live commentary during the LADEE mission launch on Friday, September 6th, at 7:30pm PST.  The event, sponsored by the Planetary Society, will be broadcast live on KPCC.  The LADEE (Lunar Atmosphere and Dust Environment Explorer) mission will orbit the Moon for approximately 100 days to collect information about its atmosphere and the lunar dust environment.  Tune in to learn more about this exciting mission!

July 19, 2013

Diviner Intern Profile: Erin Leonard

Erin Leonard (age 21) is a rising senior at UC Berkeley double majoring in Astrophysics and Planetary Science.

erin-leonard

What is your research project this summer at JPL?

I aim to research how the porosity of a lunar soil sample affects its thermal emission, which is expressed by the surface temperature. In order to do this I am conducting a series of heating and cooling tests on lunar soil samples of varying density in SABEL (Simulated Airless Body Emission Laboratory) under atmospheric conditions, vacuum, and vacuum with a LN2 cooled thermal shield. If the density of the soil sample affects its thermal emission it may also affect its spectra which connects to the research of my mentor, Benjamin Greenhagen, and others.

Why did you choose to study lunar science?

I chose to study lunar science this summer because early last spring I did a research report on lunar volatiles and this sparked my interest and caused me to look for other current lunar research. I love how there are so many things that we can learn from the moon and then possibly apply the same knowledge to other areas in planetary science.

What are your career goals?

My career goals are broad, but I know I want to get my PhD and eventually do research.

What have you learned so far as a Diviner intern?

As a Diviner intern I have learned about the importance of being able to adapt your work or your research goals in the face of complications that are out of your control. I hope to continue to learn more about the groundtruth process and remote sensing on the moon.

What has been your favorite moment or the best part of working with the Diviner team?

The best part of working so far has been getting to work in the lab with SABEL and getting to know the team members and how they got to where they are today.

July 18, 2013

Diviner Intern Profile: Cliff Watkins

Clifford Evan Watkins (age 29) is a physics major and rising senior at St. Olaf College in Northfield, Minnesota.  He is originally from Eastern Pennsylvania.

clifford-watkins-photo

What is your research project this summer at JPL?

I am working with Paul Hayne to further develop a model of the equatorial cold spots found by the Diviner probe. During the summer the goal is twofold: 1) to characterize the cold spots using Diviner to measure the density profile and 2) to build a mathematical model in an attempt to refute or confirm the possibility of ballistic creation processes. This problem is interesting for the sparsity of surface data collected juxtaposed to the sheer richness of the Diviner data. Therefore the problem is described well from the top down, but very minimally from the bottom up; a situation lending itself to leaps of creative logic that having a measure of useful ignorance allows.

Why did you choose to study lunar science?

I like the idea of the moon. It is marvelous to have such an intrinsically fascinating dataset, but that would be a bit of a stretch of the truth for the only reason that I am at JPL. I am also here in order to test the waters of Southern California, and more-so I just the like the story of this. I think, retrospectively, a certain edacity for stories has led me to most of the places I have ended up heedless of some of the rather steep prices paid. This oozes directly over the numbers into the next question as the prime mover for my career goals as well.

What are your career goals?

I would like to consider myself interesting, work on interesting problems, and live in places that I can surf, cycle, and adventure. Put precisely, I would like to be able to tell of good story of the things that I have done and the times I have spent doing them.

What have you learned so far as a Diviner intern?

I have learned a lot as a Diviner intern. It is fascinating working at JPL, being surrounded by competent people and seeing the processes of the system that continues to push science forward. Moreover, I had the assumption of a more complete lunar science due to Apollo era scientific progress, but Diviner has shown this to be patently false. And lastly, I have learned that a lot more work is put into a lot of the details than I ever thought possible.

What has been your favorite moment or the best part of working with the Diviner team?

Thus far, and this is probably the nerdiest, but most honest, thing I can say; my favorite moment has been staring at a whiteboard with Paul Hayne as we try to get the unit analysis correct while developing potential models. Putting ideas into words and hearing someone be interested enough in them to thoughtfully critique their structure from the standpoint of an expert is a game-changing experience.

July 17, 2013

Diviner Intern Profile: Jason Platt

Jason Platt (age 18) is a Physics major and rising sophomore at Stanford University.  He is originally from San Marino, California.

Jason Platt

What is your research project this summer at JPL?

At JPL I am helping my mentor construct thermal models of the Apollo 17 heat flow probe in order to more accurately determine the thermal conductivity of the lunar regolith. Discrepancies in the data returned by the probe have caused many to call into question the validity and reliability of the data returned by the experiment. If we can correctly incorporate these discrepancies into our models then a mystery will be solved and scientists can start to utilise the only proper thermal data ever recorded of the lunar soil.

Why did you choose to study lunar science?

My father used to take me out to the desert when I was little and take me stargazing.  I’ve been fascinated by space ever since and so when an opportunity opened at JPL in planetary science I jumped at the opportunity. I’ve never studied lunar science before but I hope to keep exploring and broadening my knowledge.

What are your career goals?

I hope to continue my education and see where it takes me.

What have you learned so far as a Diviner intern?

I have learned the value of patience when it comes to doing research. There have been a number of times that I’ve had to throw out many days work and start again from basic principles. More concretely, I have also learned the basics of heat flow as well as to use computer modelling programs.

What has been your favorite moment or the best part of working with the Diviner team?

My favourite moment happened when I came into work one day and found my mentor’s office completely covered in ridiculous photographs. The people in the planetary science division and Diviner team are fun, sociable and often completely ridiculous. I could not ask for a better place to spend my summer.

July 15, 2013

Team Welcomes 2013 Summer Interns

Diviner Team Members Paul Hayne, Ben Greenhagen, and Matthew Siegler are hosting the first class of Diviner interns this summer at the Jet Propulsion Laboratory in Pasadena, CA.  Three interns from top colleges throughout the country will spend ten weeks on Diviner-related projects before returning to their home institutions to finish their undergraduate degrees. Learn more by reading Q&As with Diviner interns Jason, Erin, and Cliff.

Below, Paul, Ben, and Matt answer a few questions about the Diviner internship program.

What do interns learn over the course of their stay?

Paul: Students learn about the Moon and more importantly, how to do science! Most summer students work on a specific problem related to their mentor’s major field of research. They develop a hypothesis, acquire and analyze data, test the hypothesis and interpret the results in order to improve our understanding of the Moon. Summer students also have lots of interaction with their mentors and other interns, and are able to attend weekly seminars on a range of planetary science topics.

How are interns selected and what should students do if they are interested in becoming a Diviner intern?

Paul: Internship programs are run through both Caltech and JPL, and interested students can learn more here.  Some of the programs require a research proposal, which the applicant writes with the help of the prospective mentor. Here is some advice from the SURF program (which includes two of our Diviner interns).

In general, we are looking for students with a strong academic background (or demonstrated potential) in geology, physics, or astronomy (or related math/science). They also have to express interest in studying the Moon! Because we JPLers tend to have busy schedules, we also look for people who are likely to be self-motivated.

How do you feel about hosting interns at JPL?

Matt: I definitely went into science because of my summer internships. They are what made me believe I could excel in grad school, because they are a lot more like grad school than they are like undergrad. They make you see that science is more than class work and takes different skills than you need for written tests. I doubt I would have thought science was going to be a very interesting career if I just saw what I had seen in class. I hope to pass that on to the students.

Ben: I’m always happy to help inspire the next generation.  A similar internship opportunity at the Lunar and Planetary Institute (LPI) is what got me into planetary science.

July 2, 2013

Diviner PI Awarded NASA’s Top Scientific Medal

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Diviner PI David Paige of UCLA’s Department of Earth and Space Sciences has been awarded a NASA Exceptional Scientific Achievement Medal.  This award is NASA’s top scientific honor and is given to individuals “for exceptional scientific contributions (specific, concrete scientific achievements) toward achievement of the NASA mission.”   Dave is honored for his “Breakthrough discoveries in the thermal stability of volatiles on the Moon and Mercury”.

February 7, 2013

LPSC 2013 Diviner Data Users Forum

The LRO Diviner Science Team will host a public Diviner Data Users Forum on Sunday, March 17 from 3 to 5pm in the College Park Room at the Woodlands Waterway Marriott Hotel in Houston, TX. The purpose of the forum will be to acquaint the community with Diviner’s new high-level mapped data products. These products include global maps of brightness temperature, solar reflectance, composition and thermophysical properties.  This extensive new dataset will be made available via the NASA PDS Geosciences Node on June 15, 2013. The forum will also provide an opportunity for potential users to ask questions and provide feedback to the team. This is a public meeting and all are invited.

Forum Agenda:

3:00 pm - Dataset Overview and Level 1 Data Products - D. A. Paige (UCLA)
3:20 pm - Foundation Level 1 Data Product - K. M. Aye (UCLA)
3:40 pm - Standard Gridded Data Products (Part 1 | Part 2) - J. P. Williams (UCLA) and B. T. Greenhagen (JPL)
4:20 pm - Foundation Level 2 Gridded Data Products - E. Sefton-Nash (UCLA)
4:40 pm - Questions and Discussion (All)

November 14, 2012

Diviner scientists share lunar research at UCLA outreach event

During UCLA’s Explore Your Universe outreach event, science research groups and departments from across campus share their research with the public through hands-on demonstrations and experiments aimed at students from “K through gray”.

The Diviner exhibit included animations of the Lunar Reconnaissance Orbiter launch and journey to the Moon, a lunar tour, and the LCROSS impact.  An infrared camera allowed members of the public to learn why their cars heat up when left out in the sun and how infrared cameras can see things our eyes can’t.  For more information about the event and to see more pictures and video, visit the UCLA Institute for Planets and Exoplanets.

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Elliot Sefton-Nash explains the infrared camera to interested onlookers.

Michael Aye discusses his research at the Diviner outreach exhibit during UCLA's Explore Your Universe event.

Michael Aye discusses his research at the Diviner outreach exhibit during UCLA's Explore Your Universe event.

Michaela Shopland tells members of the public about the Lunar Reconnaissance Orbiter and the Diviner experiment.

Members of the public learn about the Lunar Reconnaissance Orbiter and the Diviner experiment.

Thanks to Diviner team members Paul Hayne, Raquel Nuno, Michael Aye, and Elliot Sefton-Nash for volunteering their time!

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