Monday, 31 October 2016

Anatomy of a Martian Crash

Schiaparelli’s Crash Site
Crash site of the Schiaparelli lander as viewed by  the 
High Resolution Imaging Science Experiment on the
Mars Reconnaissance Orbiter,
imaged on October 25th, 2016.

Image Credit: NASA/JPL/University of Arizona

The planet Mars has seen its share of mechanical disasters. An interesting look at this phenomenon is presented in a Universe Today article written just this past April. But never before have we had the capability to scrutinize a distant crash in such detail.

The Schiaparelli Descent and Landing Demonstrator Module (EMD) crashed into the Martian surface on October 19th at approximately 3 pm (Greenwich Mean Time). The crash was viewed by no less than three instruments. Data from the lander’s descent was recorded by the ExoMars Trace Gas Orbiter (TGO), which had travelled to Mars with the Schiaparelli lander. Collection and transfer of data was also assisted by the ESA Mars Express orbiter, which has been parked at Mars since December of 2003, when it too lost its accompanying lander the Beagle 2. In addition, measurements were made from Earth, using the Giant Metrewave Radio Telescope (GMRT), an experimental telescope array located near Pune, India. Scientists and engineers are still poring over this glut of data to determine what happened. However, several details have already become clear.
Farewell Schiaparelli
Image Credit: ESA – B. Bethge

Schiaparelli’s 6-minute descent through the martian atmosphere was intended to proceed in three stages. The first stage was to be free-fall under the protection of two heat shields, at front and back of the module. In stage two, a parachute (12 meters in diameter) was to be deployed, reducing the lander’s descent speed. In the third and final stage, the parachute and back shield were to be released, so that a set of nine thrusters could fire, further slowing the lander down and bringing it to a soft landing at Meridiani Planum near the martian equator.

Preliminary analysis of the collected data indicates that, for some reason, the thrusters switched off prematurely at a height of 2-4 km above the martian surface. This resulted in a long free-fall for the lander module, much longer than had been planned, and the lander crashed into the surface at speeds of more than 300 km/h. The hydrazine propellant tanks, which fueled the thrusters, are expected to have still been fairly full when the thrusters switched off, so they may have exploded on impact.  The descent data is still being analyzed, so more accurate details may become available in the future.

But monitoring the lander’s descent was not the only observation that was planned for Schiaparelli. Two cameras on NASA’s Mars Reconnaissance Orbiter (MRO) spacecraft were scheduled to image the predicted landing ellipse, a 100 km by 15 km area where the lander was expected to touch down. This allowed the location of the crash to be identified and the aftermath to be studied.

Finding Schiaparelli
Crash site of the Schiaparelli lander as viewed by the Context Camera on the NASA Mars Reconnaissance Orbiter. Image on the left shows the full view, while the image on the right shows a zoomed-in view. Both images toggle between data collected on Oct. 20th, just after the crash, and data collected on May 29th, five months before the crash. The images are located at approximately 2 degrees south latitude and 354 degrees east longitude, are oriented with north towards the top, and have a resolution of 6 m/pixel.
To learn more about this image, go to this ESA website.

Image Credit: NASA/JPL-Caltech/MSSS
MRO’s low-resolution Context Camera (CT) was scheduled to cover the anticipated landing site on Oct. 20th, and so was the first to image the suspected crash site. Scientists compared these images to previous ones, collected by the same instrument less than 5 months earlier, and found exactly where the lander came down. Despite the fatal difficulties, the module landed very close to its intended landing spot, only 5.4 km west and well within the predicted landing ellipse.

The discovery image shows the locations of two distinct components of the lander module. The dark fuzzy patch in the upper part of the image is where the lander crashed, forming an impact crater. The crater itself is fairly small, while the bulk of the dark patch, which is roughly 15 x 40 meters in size, represents surface material that was disturbed by the impact. Below the lander crash site, a small white dot can be seen. This is the module’s jettisoned parachute.

A Closer Look
Higher resolution images of the Schiaparelli lander as viewed by NASA’s Mars Reconnaissance Orbiter HiRISE camera on Oct. 25th.  Zoomed-in views are provided for each identified impact point resulting from module’s crash.
In the image, north is up; west is to the left, and the resolution is 29.5 cm/pixel. The brightness of the zoomed-in sections have been individually adjusted to best reveal the features in question. In addition, the image is corrected to adjust for the fact that HiRISE acquired them at an oblique angle. As a result, the scale bar in the main image is only indicative.
To learn more about this image, go to this ESA website.
Image Credit: NASA/JPL-Caltech/University of Arizona
On October 25th, MRO’s High Resolution Imaging Science Experiment (HiRISE) took a closer look at the crash site.  Close inspection of the resulting image revealed several new insights. At the bottom of the image, the rear heat shield can be seen, still attached to the parachute. At the top right of the image, a new crater was identified and attributed to impact of the front heat shield. Finally, the crater formed by the main lander impact is resolved in the image centre.

The Schiaparelli lander’s impact site consists of a central dark spot, an asymmetrical deposit around the dark spot, and a long dark arc on the north-east side. The dark spot is about 2.4 m across, which is consistent with a crater made by a 300 kg object impacting at a few hundred km/h. The crater is predicted to be about 50 cm deep and it is hoped that more details will be visible in future images. This will be necessary to help explain the enigmatic asymmetric and arc features, which are currently not well understood.

Asymmetrical deposits are not uncommon around impact craters, but such craters are usually formed by meteors travelling at speeds of 40,000 – 80,000 km/h. In such cases, the presence of asymmetric debris around a crater implies that the meteor came in at a low angle (closer to horizontal), so material was ejected from the crater in a preferred direction, with more ejecta material deposited in the direction of travel. However, the Schiaparelli lander is thought to have been travelling at only 300 km/h and descending almost vertically at the time of impact, so directed ejecta would not be expected. Also, the lander entered the atmosphere travelling from west to east. Thus, even if the impact was not vertical, the preferred direction for ejected material would have been to the east of the crater, not to the west as is seen in the HiRISE imagery. It is possible that the module’s propellant tanks exploded in a westerly direction, producing the asymmetrical ejecta, but more analysis is required to confirm this idea.

The long dark arc to the north-east of the crater is also currently unexplained. One suggestion is that an exploding propellant tank may have created this arc by disturbing the surface soil.

Despite many remaining questions, the abundant data from the Schiaparelli EDM crash is allowing us to study an extra-planetary accident in more detail than has ever been possible before. We can only hope that more data will bring more insights into how to avoid such disasters in the future.

Mars Reconnaissance Orbiter views Schiaparelli Landing Site.
ESA ExoMars News, Oct. 21, 2016

Detailed Images of Schiaparelli and its Descent Hardware on Mars.
ESA ExoMars News, Oct. 27, 2016

Tuesday, 31 May 2016

Discover the Smithsonian Moon Exhibit On-Line

This February the Smithsonian National Air and Space Museum in Washington D.C. opened an exhibit titled “A New Moon Rises: New Views from the Lunar Reconnaissance Orbiter Camera.” The exhibit, which showcases some of the most spectacular images acquired by the Lunar Reconnaissance Orbiter Camera (LROC) since 2009, is scheduled to run until December 2016. If you live in Washington D.C., or are planning a trip there in the near future, I would encourage you to check out the exhibit, especially since admission to the museum is free.

For the rest of us, the Smithsonian has kindly provided an on-line version for us to experience. Like the physical exhibit, the virtual “A New Moon Rises” exhibit is divided into six themes (Global Views, Exploration Sites, Discoveries, Vistas, Topography and Craters), which can be accessed through the menu bar at the top of the page.

Within the virtual exhibit, you will find some truly spectacular images. Some of my favourites are highlighted below.

Unlike the Earth, the Moon’s axis is not tilted very much. This means that sunlight hits the lunar poles at a very low angle (like at sunrise or sunset on Earth) pretty much all of the time. Some high areas, like mountains and crater rims, will get at least some sunlight most of the year, while low areas, like crater depressions, will get effectively no sunlight, ever. This image of the south pole was created by combining thousands of images taken over a lunar year. It shows what percentage of the year each area is hit by sunlight. The shading is scaled so that areas that get sunlight 100 % of the time show up as white, while those that never get sun are black.  The black areas, known as permanently shadowed regions, get very cold and so are believed to be places where water ice is trapped and preserved from evaporation by the hot sun.
Image Credit: NASA/Goddard Space Flight Center/Arizona State University 

Pairs of stereo images from the LROC Wide Angle Camera, along with altimetry data from the Lunar Orbiter Laser Altimeter, allow topography to be determined for the entire lunar globe.  This image shows the topography of the western limb of the Moon, centred on the Orientale basin.  Orientale is the youngest of the large lunar impact basins and has not been flooded by much lava. As a result, its topography is readily revealed, showing multiple impact basin rings. Here, reds and browns denote high elevation, greens and blues represent medium elevation, and deep blues and purples show areas of very low elevation. 
Image Credit: NASA/Goddard Space Flight Center/Arizona State University 

Giordano Bruno is one of my favourite craters (of course, I covered it in one of my earliest Planetary Geolog posts). This image shows the crater from an oblique angle, which highlights the topography of the rim and floor features of the crater. The sunlight also shows off the interesting landslides on the crater walls.
Image Credit: NASA/Goddard Space Flight Center/Arizona State University 

I hope these few examples will inspire you to explore the virtual “A New Moon Rises” exhibit yourself and find your own favourites.

A New Moon Rises: New Views from the Lunar Reconnaissance Orbiter Camera. Smithsonian National Air and Space Museum On-line Exhibits, Accessed May 31, 2016.

Thursday, 31 March 2016

Many Small Nuggets from the 47th Lunar and Planetary Science Conference

Tuesday Night Poster Session at the LPSC 2016.
I might be in there somewhere...
Image credit:  Lunar and Planetary Institute. 

This year's Lunar and Planetary Science Conference (LPSC) was another success. I again went as an independent researcher, but this time I was also looking for employment opportunities. I got a few leads, which I will follow up in the next few weeks.

I also rejoined the official LPSC microblogging crew. Some of you may have followed my short posts on Google+ during the conference. As usual, I am reproducing my entire complement of LPSC microblogs, plus appropriate links (if available), here on the Planetary Geo Log. Again, the intent is for you to digest a few small nuggets at a time. I hope to write up some of these in future blogs, so keep an eye out. If you would like to learn more about any of the posted topics, please feel free to make a request in the comments.

Sunday March 20, 2016
1)  Hello folks. I am at the Lunar and Planetary Science Conference again this year and will be microblogging on Google+. I hope you enjoy my observations of the conference.  

2)  Attended this year's #Microsymposium57 before #LPSC2016. I'll be posting some highlights......

3)  David Paige has found that there are more volatiles in low latitude craters at the lunar poles, because those craters catch the poleward-migrating volatiles before they can reach the high latitudes of the poles. #Microsymposium57 before #LPSC2016.    

4)  Barb Cohen is looking for "operationally useful amounts of water" on the Moon, which means large quantities. She proposes this can be done using cube satellites. #Microsymposium57 before #LPSC2016.    

5)  Mahesh Anand tells us that ESA considers the Moon to be the primary target for human exploration after the ISS. #Microsymposium57 before # LPSC2016.    

6)  Tony Colaprete and Jen Heldmann told us about the proposed Resource Prospector mission. It consists of a rover that will take measurements and samples at several locations on the lunar pole. #Microsymposium57 before #LPSC.    

Monday March 21, 2016
1)  Catherine Johnson shows that the magnetic field on Mercury is strongest in the Caloris basin and the magnetic field is at least as old as the Caloris basin.   

2)  L. Hood noted that you need a long-standing magnetic field to explain the magnetic signatures seen at Caloris and Sobkou basins on Mercury. So, Mercury would have had a magnetic dynamo at the time these basins formed.    

3)  The models of P. James suggest that the lithosphere of Mercurry is 32 (+/-15) km thick.    

4)  C. Fasset shows that crater degradation on Mercury happens much faster than on the Moon.    

5)  Robbie Herrick noted that Mercury has more craters <10 km in diameter than would be expected for the number of craters >10 km in diameter. This would be due to a larger number of secondaries. If so, the oldest surfaces on Mercury could be 100 m.y. younger than previously estimated.    

6)  Congratulations to last year's Dwornik student award winners:
      Robert Jacobson - U Tennessee,
      Hanna Susorney - John Hopkins,
      Johnathan Oulton - Florida State,
      Hank Cole - Colorado School of Mines.   

7)  Alan Stern reported on the New Horizons mission results so far. Although the flyby of Pluto is complete, only half of the data has been transmitted, because lower transmission rates were selected to keep costs down. The other half of the data is still to come. What additional exciting things will we learn about Pluto?    
(PDF Presentation of Alan Stern's Talk)
(Video of Alan Stern's Talk)

8)  Pluto has 4 small satellites in addition to Charon. The outer-most, Hydra, rotates 100 times about its axis for each orbit around Pluto. It's quite mesmorizing in this animation that Alan Stern showed.
(Animation of Pluto's Satellite's Orbits)
Comment on Google+: Wow. Any particular reason for that? (spin:orbit resonances?)
My reply: No, they're not quite sure. Just sat in on a talk by S. Porter, where they discussed the small satellites. All have retrograde rotations, which is odd, so they suspect this may be related to some kind of tidal state.

9)  Pluto's large, bright, smooth plane, called Sputnik Planum, is thought to be an ancient impact basin that is filled with nitrogen ice. This ice shows evidence of glacial flows at the northern edges according to Alan Stern.    

10)  Using GRAIL Gravity data from the Moon, Maria Zuber showed that cryptomaria (hidden mare deposits) in the Schiller-Zucchius basin do NOT extend to a depth of 10 km. This is not a surprising result, but it's good to have a confirmation of this.   

11)  Tony Colaprete reported on LADEE data for the thin lunar atmosphere, or exosphere. Titanium and magnesium concentrations in the exosphere are somewhat correlated with mafic deposits on the surface and aluminum deposits are somewhat corelated with surface highlands, though the surface compositions cannot completely explain the exosphere compositions.

12)  The Pluto/New Horizons research articles in Science are all open access!! Enjoy...    

13)  S. Porter tells us that the moons of Pluto are in extremely stable orbits and their surfaces (as far as we can tell with the limited available data) are cratered and old. So, these moons are not new or ephemeral objects, but have been orbiting around Pluto for a long time.    

14)  NASA Night at #LPSC2016. NASA is looking for community input on how we use NASA data. Foreign input is also welcome. There will be a link posted on the LPSC webpage with instructions on how to submit your input. I will update this microblog post with the link as soon as it goes up.
Instructions for submitting input can be found at: (

15)  NASA Night at #LPSC2016. Cosmoquest was mentioned as one of the organizations that won an Education and Public Outreach grant this year. Congratulations #Cosmoquest!

16)  NASA Night at #LPSC2016. Jim Green tells us that the NASA planetary science budget got $270 million more than was requested this year!!
Total budget is $1.63 billion.    

17)  NASA Night at #LPSC2016. This was Jim Green's closing slide for questions.

18)  Really enjoyed meeting old friends and new at the Students Reception.    

Tuesday March 22, 2016
1)  Jeff Plescia told us that impact melt flows on the Moon show evidence of multiple pulses of material from the same impact.   

2)  Jason Cook talked about the distribution of non-volatiles on Pluto. Apparently this means water, which I think of as a volatile. But water does not act like a volatile on Pluto, because of the extremely cold temperatures. Jason finds that water is widely destributed on Pluto, predominantly as fine particles.    

3)  Misha Kreslavsky found large-scale dendritic patterns, with a topographic range of 20 meters, in parts of the lunar maria.    

4)  Lisa Gaddis showed that M3 data can be used to identify volcanic pyroclastic deposits on the Moon.    

5)  Tom Giguere suggests that the floor of Gassendi crater, a floor-fractured crater on the north-west shore of Mare Humorum on the Moon, shows evidence of drained lava lakes.    

6)  Carl Allen used Diviner data, collected during a lunar eclipse, to show that pyroclastic deposits in the Aristarchus region of the Moon cool faster than other materials in sinuous rills, maria, or mare rays. The thermal inertia of pyroclastic material must, therefore, be lower, possibly due to a much finer grain size.    

7)  Carolyn van der Bogert showed that the Dark Mantle Deposits of Taurus Littrow are actually older than the surrounding maria, even though they look younger. This is because small craters in the dark mantle deposit are in saturation and have experienced preferential degredation, while the small craters in the nearby maria are still in production, resulting in more craters at that size.    

8)  Tuesday poster sessions were such a whirlwind, I didn't get a chance to microblog about anything.

9)  30th annual Hawaii Party was it's usual fun. Really enjoyed chatting with Tom Giguere and Steve Ruff.   

Wednesday March 23, 2016
1)  Daniel Moriarty and Makiko Ohtake presented back-to-back competing interpretations for the interior of the South Pole-Aitken basin on the Moon. I confess, I am confused....    

2)  Noah Petro presented work that supports the presence of cryptomare deposits in the Bhabha region of South Pole-Aitken basin on the Moon. During the question period, Apollo 17 astronaut Jack Schmidtt noted that one of the flat-floored irregular craters in the region may not be a flooded impact crater, but rather a volcanic caldera related to the cryptomare volcanism period.    

3)  Paul Spudis identified a number of units around the edges of Mare Crisium on the Moon. These units poke through, and so pre-date, the mare material of the basin. Paul suggests that these may be remnants of the Crisium impact melt sheet and so would make good targets for future sample-return missions.    

4)  Based on low-angle impact experiments, Pete Schultz proposes that so-called "double impacts", which have been identified in GRAIL gravity data from the Moon, may actually be due to a single low-angle impact. What happens is the approaching bolide hits the surface at an oblique angle, causing the top of the bolide to decapitate and hit the surface in a second location down-range, producing what looks like a double impact.    

5)  Shared from Stuart Robbins.
Lisa Gaddis: NASA’s Cartography & Imaging Sciences Node contains >850TB of data, growing at ~120TB/yr.    

6)  Just uploaded the electronic version of my #LPSC2016 poster. You can see it here...    

7)  Pamela Gay told us about the exciting funding developments happening for the #Cosmoquest project during our Cosmoquest community meeting at #LPSC2016.    

8)  At the #Cosmoquest community meeting (during #LPSC2016), Andrea Jones encouraged us to spread the word about International Observe the Moon Night, happening this year on Oct. 8, 2016. Now is the time to start planning your event. Don't forget to register your local event, whether it's a big museum function or a small neighbourhood get together, so InOMN can highlight how global this celebration truly is! Instructions on how to get involved can be found under the Get Involved tab on the web link below.    
Image credit:  Wikipedia. 

9)  New Vocabulary Word from R. Beyer's talk at #LPSC2016. Frustum: A diagram illustrating the angle a camera is pointing towards the target surface.    

10)  Planetary Spatial Infrastructure session at #LPSC2016 was very interesting. Best quote has got to be "Cartography is important to cartography." This means that Cartography, as the manipulation of digital data so that it can be presented in a map, is important to Cartography, the process of creating maps.     

11)  LEAG Networking Session at #LPSC2016. A group of young scientists are gathered around Apollo astronaut Jack Schmidtt, soaking up his wisdom.    

12)  Smart people tend to be more prone to unintentional bias. They tend to feel they are immune to this bias, because they are smart. So recognize that you have biases, know what they are, and work to overcome them. #WomenInPlanetaryScience and #LPSC2016.    

13)  Being self-aware of your own biases and working on those is not enough. The culture and institutions in the community need to be changed too, to help overcome this bias problem. Senior and mid-career members, who are less vulnerable, need to take the initiative in this regard. #WomenInPlanetaryScience evening at #LPSC2016.    

14)  Discussion section of the #WomenInPlanetaryScience evening at #LPSC2016. was great.    

Thursday March 24, 2016
1)  Systems engineering is ensuring that you don't design misunderstandings into your system. #NextGenWorkshop Scientists and Engineers: Learning to Work Together at #LPSC2016.    
(Video about system engineering, recommended by the presenter, Lee Graham )

2)  Think of mission requirements as dollars in a different form. You want the minimum necessary requirements to cover the scope and objectives of your entire mission, no more and no less. #NextGenWorkshop Scientists an Engineers: Learning to Work Together at #LPSC2016.    

3)  Totally amazed by the interesting people who stopped by my unconventional planetary poster about using financial modeling techniques for identifying basalt spectra.    

4)  The annual Arizona Party was fun, but I was too beat from my poster session to take advantage of the dance floor and DJ. Does anyone know if there was much dancing this year?    

Friday March 25, 2016
1)  Michael Nayak found that magnetic data from the South Pole-Aitken basin suggests the existence of several new magnetic paleo-poles on the Moon, which had not been previously identified.    

2)  Lon Hood suggested that the absence of magnetization on the rims of large lunar impact basins may be due to their being erased by subsequent volcanic flooding. However, Mark Wieczorek pointed out that his earlier work shows that mare layers cool too quickly for their heat to be able to erase the magnetic signature.    

3)  Rona Oran used simulations to model the behaviour of the lunar magnetic field during large-scale impact events. Her work shows that the magnetic field is increased all over the Moon during an impact event, not just at the antipode. However this increase is too small to explain observed magnetizations, thus supporting a stable core dynamo as their source.    

4)  Mark Wieczorek gave a fascinating talk about the depth of lunar magnetization. Almost the entire Moon is magnetized and most of it has a deep origin. This means that impact magnetization, which only affects the surface, is not the dominant magnetizing process on the Moon. Similarly, volcanic intrusions cannot be used to explain magnetism on the far side, where volcanism is very limited. Therefore, most of the magnetization seen on the Moon must have been accumulated during slow cooling of the primordial crust in the presence of a stable dynamo. Magnetization of the farside crust would have been locked in by 230 million years after the formation of the Moon, so the dynamo must have been in place by then. This is even earlier than the oldest magnetized samples we have from the Moon, which have been dated at 4.25 billion years old (~250 million years after the formation of the Moon).    

5)  D.A. Patthoff mapped two populations of ridges on Enceladus, one old and one recent. Based on these, the following tectonic history was proposed: compression of the crust associated with its formation, followed by a long tectonically quiet period, culminating in a recent period (<100 m.y.) of compression possibly associated with thickening of the crust due to cooling of the underlying ocean. What is not known is what are the implications of this history or the evolution of life and how long before the ocean completely freezes over.

6)  Mike Bland proposes that the grooved terrain of Ganymede is formed when magmatic intrusions heat the overlying crust. This allows convection in the intrusion to push the overlying crust and bunch it up (like a table cloth) to form sets of parallel grooves.    

7)  Audience request for some Game of Thrones names on Charon.   

8)  We have reached the end of #LPSC2016. Thank you so much for letting me bombard you with my observations. I hope you enjoyed it, I know I did. Until next year....