Posted on Jun 26, 2013
So I’m probably Jack Swigert.
As a fall-back, last-minute replacement for an oversubscribed colleague, I have no illusions of my role on this mission – Rover Module Pilot and Bag Carrier. A job that I have undertaken with quiet stoicism and gin.
It is now Day 2 of our 10 day mission to our Mars (analogue) field site. After a routine launch from Cape Gatwick and a 3 hour cruise phase we touched down on a terrain showing definite signs of life. Our launch mass limit was overcome by a very helpful close-out crew member combining our 9 bags and boxes and taking the average.
The post-landing checkouts took longer than expected, with calculators needed for the complicated three-way conversion of alcohol to Krona to pounds. With breakfast now sorted for the mission, we turned our attention to pulling the release cables on our pre-booked rover. As with all space missions, some things never go to plan, and tasks that would be simple back home actually take much longer (and a V8 engine) when tested for real.
The original Rover was quickly judged to be woefully too small for all of our instruments, and so we had to drive to a depot – definitely not with the hand brake accidentally left on – to have a roof box fitted. Which still left all of our essential boxes on the floor. What is the Icelandic for balls? So despite having a big loud exhaust vent and a proud rallying history (probably literally in the case of this rover), the original Rover had to be upgraded in situ – an ability I highly recommend for future Mars missions.
So our current Rover is now a monster four wheel drive monster V8 monster (plus a roof box), which might have a fuel issue on longer missions. I think I spent more time watching the fuel gauge move in real time than on the road, but it was an absolute necessity for this trip. The upside is that I’m still daydreaming over the noise from in front of us.
We are now at base camp for the mission in Myvatn, and it’s beautiful. Not quite magnificent desolation, as there is way too much energy here, but mesmerizing all the same. We prepared and ate our first meal of the mission (never dehydrated veggie curry), and then headed for high ground for some geological context. And a mega-stitcher photo opp.
It’s now late, just time for us to send our communications back home, which with the time delay gets there one hour ahead of us here. And now we have to plan for tomorrow.
We will probably do a reconnaissance drive and walk before deciding where to actually deploy our instruments. We have a visible and near-infrared “portable” field spectrometer (think Ghostbusters), the latest version of the test ExoMars PanCam stereo and high-resolution cameras (think Wall-E without wheels), and a rock hammer (think handsome and clever geologist). Oh and I’ll be doing some fancy 3D stuff with cameras too hopefully.
I’ll explain the science of the mission later on I think. Or I strongly suggest you check out my fellow analogue-astronaut Dr Claire Cousin’s field blog. She’s talking way more sense than me.
So I’ll sign off this mission log with a photo of our field base. Iceland – I love you almost as much as Mars.
Posted on Oct 8, 2012
Since my last post I’ve had a few requests for maps of the Bradbury Landing site, and the larger Gale Crater area. So I thought I’d share some of these maps as best I can.
The maps are just screenshots from my Gale GIS project, showing different data at different zoom levels. I’ve omitted grids, scale bars and keys in the hope that people can use the images as they wish, basically crop at will, and so hopefully be of some use to them.
The data all come from NASA’s Planetary Data System and so credit should be given to the specific teams who collected the awesome data:
All data were imported into a GIS and georeferenced, although the elevation data have not been normalised (hence some near-vertical ‘stripes’ in contours etc.). Links to GIS-friendly PDS data can be found on the fantastic USGS MRCTR GIS lab page (the old, but still active, page is called PIGWAD). These are a great place to start looking for planetary data and instructions on how to get started with them.
I made maps at 6 different zoom levels, to bring out different features. Level 1 covers the largest area – all of Gale Crater – whereas level 6 concentrates on the landing site itself. Topography data come from either MOLA (levels 1-3) or HiRISE stereo DEMs (levels 3-6), with coloured contour intervals at 500, 100 and 10 m. Click on the levels to download the whole of that folder, or individual images for a single file.
Level 1 (12 MB)
– THEMIS (day IR) (1.5 MB)
– THEMIS (night IR) (1.5 MB)
– THEMIS (day IR) + MOLA contours (2.9 MB)
– THEMIS (day IR) + MOLA colour + contours (4.3 MB)
– THEMIS (day IR) + MOLA slope (2.1 MB)
Level 2 (34 MB)
– THEMIS (day IR) (0.9 MB)
– THEMIS (night IR) (0.9 MB)
– THEMIS (day IR) + CTX (6.3 MB)
– THEMIS (day IR) + CTX + MOLA contours (8.2 MB)
– THEMIS (day IR) + CTX + MOLA colour + contours (11.2 MB)
– THEMIS (day IR) + CTX + MOLA slope (7.0 MB)
Level 3 (140 MB)
– CTX (18.7 MB)
– CTX + MOLA contours (17.6 MB)
– CTX + MOLA colour + contours (23.7 MB)
– CTX + MOLA slope (18.8 MB)
– CTX + HiRISE contours (16.6 MB)
– CTX + HiRISE colour + contours (23.7 MB)
– CTX + HiRISE slope (27 MB)
I hope that these are of some use. Feel free to contact me if you have any questions about the data or maps.
Posted on Aug 20, 2012 5 Comments
Well, here we are then…
Curiosity has landed safely in Gale Crater on Mars. You know, I’ll never get tired of writing that. So much has been already written about the mission, the people, and what’s going to happen over the next few days, weeks and years. And I loved reading them all.
But I thought I’d try and offer here a bit more on the area that Curiosity is going to explore over the next martian year (and hopefully beyond). Now we know where Curiosity is on the surface we can take a look at the surrounding terrain and figure what’s there and where’s interesting. The science team are probably having a great time right now doing just that.
But before I start, I should make a disclaimer: Gale was always my favourite.
No honestly. It wasn’t really anything to do with the science, rather just from sitting back and imagining what the view would be like when we got there. And do you know what? It’s even better than I could have imagined. Even the first low-resolution hazcam, that showed the mound in the middle of the crater (more on that later), left me speechless.
And the view will only continue to get better as more images are returned and new vistas open up. More than that though, the science will be fantastic.
It’s worth pointing out that all of the landing sites that made it through to the final stages would have been amazing too. I was lucky enough to go to one of the later MSL landing site discussion meetings, where the case was made for each of Gale, Eberswalde, Holden and Mawrth. I wasn’t there representing a particular site and didn’t give any presentations. Instead I was there to take part in the overall discussion, and as an early-career researcher learn how processes like these happened. After each site’s session, typically a whole morning or afternoon, I was swayed by the science case that had been made. Each had amazing geology to offer, their own reasons for going there. And I don’t doubt that any of them would be fantastic field sites for Curiosity.
But in the end Gale was chosen. To my own mind, one of the reasons for this might be that there seems to be a coherent story behind how we think Gale might have formed and evolved. It offers a nice hypothesis that can be tested. And that’s science, right?
So let’s get on with it – time to try and flex some GIS muscles. Let’s start with a base map of the area that we should get very familiar over the next few months.
So we know that Curiosity was always targeted to land in the safe, flat floor of Gale Crater. But Curiosity has in fact landed very nicely close to the front edge of what is thought to be an alluvial fan, which are common features on Earth formed by water and debris. More than that, this frontal lobe of the fan also has a high thermal inertia – Emily Lakdawalla explains what that means here.
So here’s Curiosity, with a little dark area around it kicked up during the descent, and the recently-announced first drive target of Glenelg. It’s not that far away, about 400 m, and sounds like a perfect place for the rover drivers and scientists. The drivers can see how Curiosity handles on another planet with this not-too far drive, whereas the scientists get the advantage of three different units for the price of one. A triple junction like this is a fantastic place to work out the relative stratigraphy of the units.
And the stratigraphy should be interesting. The high TI unit, part of the alluvial fan is actually lower than the unit that Curiosity is sat on currently. Now that either means that the fan formed later, but then why is it lower? So it more likely represents a lower unit that has been exhumed (effectively exposed by erosion of material above). The third unit could lie stratigraphically between the two other units, but to be honest, this is just one idea and I’m guessing – the science team will have lots of ideas that they’ll want to test.
So, can we see Glenelg from the landing site? Well, probably not. The image above uses the HiRISE digital elevation models (DEMs) to show the areas that should be visible from 2.1 m above the landing site – i.e. from Curiosity’s mast cameras. In the past I’ve found these predictions to be very sensitive to the exact location of the point I put down, but it does show that the slight ridge to the west of Curiosity obscures the view that way, which seems to match the images so far.
Taking a closer look at the possible traverse to get to Glenelg shows that it shouldn’t be too tricky. It’s downhill by about 20 m, with slopes no greater than about 8 degrees (and which could be avoided if need be). We’ll probably see that target area after about 180 m of driving, once over that little lip. And then it’s off to explore the edge of a probable alluvial fan.
But let’s get back to the bigger picture. The alluvial fan is just an added bonus study site upon landing – the main goal has always been the mound in the middle of Gale Crater, called Aeolis Mons (and given the informal name Mount Sharp by the mission team). The part of the mound that looks (1) the tastiest and (2) free of nasty dunes is to the south-west of Curiosity, about 8 km away from the landing site.
And the reason that this part of the mound is so interesting comes from evidence provided by orbiting spacecraft, particularly the Mars Reconnaissance Orbiter (MRO). That isn’t to say that Gale hasn’t been of interest before that mission – it really has – it’s just that only the technology on MSL has allowed the landing ellipse to shrink enough to touch down safely in the crater floor. In fact Gale is just one, great, example of a group of craters that all have been filled to some extent and then eroded back to reveal stacks of sediments. And sediments are interesting to geologists because they often reveal, amongst other things, detailed information about how they formed and the timescales involved.
In the case of Gale, there are hundreds of spectacular layers exposed in the mound, many of which are directly accessible to Curiosity. But the most intriguing part of the mound, to my mind at least, is the geochemistry revealed by the CRISM instrument on MRO. In 2010, Ralph Milliken and colleagues found a diverse suite of mineralogies locked up in the rocks in the mound. They saw the olivine-rich material that makes up those beautiful dunes skirting the base of the mound, but then a composition within the exposed bedrock of the mound itself that not only provided evidence of water, but also of changing environments. In a word: diversity.
At the lowest parts of the mound there are phyllosilicates, or clay minerals, which then transition to more sulfate-rich minerals at slightly higher elevations, before a whacking great big unconformity marks the transition to anhydrous minerals. So here was a sequence – clays to sulfates to dry – exposed and within reach of an in situ mission.
Now this was fascinating, because the paradigm that had emerged over the previous decade or so, and formalised by Jean-Pierre Bibring and colleagues in 2006 with data from Mars Express, was of seeing that same sequence exposed all over Mars. The OMEGA instrument showed that phyllosilicates tended to be found in the oldest exposed bedrock, with younger, usually light-toned deposits, containing sulfate minerals, with the ubiquitous dry dust and sand prevalent ever since (albeit with periodic climate change and possible brief phases of water). Mapped onto the geological timescale of Mars it looked something like this.
The neat thing about this observation was that it could also be explained nicely too. Phyllosilicates tend to form from the alteration of rock, say a common basalt, when neutral water is involved. But towards the end of the Noachian period a few things happened at the same time. The magnetic field of Mars, if it ever had a substantial one, died out and the atmosphere was thinned by the solar wind. The massive volcanoes of Tharsis and elsewhere were spewing huge volumes of lava onto the surface and acidic, volcanic gases into the atmosphere. These acidic gases combined with the now reducing amounts of water to alter the rocks on the surface in a different way and produce sulfate minerals. The planet continued to get colder and dryer until it became the place we know today. Although without a massive moon like at the Earth, Mars has been subject to some extreme changes in its obliquity, or tilt, which has probably had a massive effect on the distribution of ice and possibly liquid water over the last few, maybe hundreds, of millions of years.
So that’s the paradigm in a nutshell. And determining whether the sequence revealed in the mound in Gale Crater reflects this paradigm is one of the most interesting questions that Curiosity can address. This is the neat hypothesis that I always thought would be great to address with Curiosity. It might be that Gale doesn’t reflect this apparent global trend – just because two regions have the same relative stratigraphies doesn’t mean that they formed in the same way at the same time.
But to me this is one of the joys of geology – trying to figure out the story told by small, individual areas, and then piecing them together to form a bigger picture. And that will come with time.
A final point though. One of my favourite images from the whole of planetary science comes from Spirit. Now Spirit had a tough life, always the ugly sister to the golden-child Opportunity. But one day, while driving backwards, dragging its broken wheel behind it, Spirit accidentally dug a little trench with its immobile wheel. And revealed in this trench, just centimetres below the ubiquitous red dust and sand, was a bright white material completely at odds with everything around it. This white material turned out to be almost pure amorphous hydrated silica, which on the Earth we call opal. So Spirit had, purely by chance, found a mineral that not only forms with water but also contains it locked up in its crystal structure.
So that’s why I’m excited about Curiosity. It will address the large science goal, and many more too, but the serendipitous findings that happen along the way could well end up being the most important. The fact that we’re here and looking means that this endeavour will always be full of discoveries.
EDIT 22/08/12: Deleted “Skycrane” from explanation of shrinking the landing ellipse. Thanks to those that spotted – I knew this, but apparently my fingers didn’t!
Posted on Jul 30, 2012
Well, it’s time to get tooled up for the upcoming landing of Curiosity on Mars.
I’ve been putting together a GIS of the landing site, using as many data products as I can find, which hopefully will come in handy later on. Everything was done by importing all the HiRISE data into ArcGIS 10, fiddling with the format slightly (using the USGS instructions here), and combining with other Mars data products (see here for loads of information on where to get them).
After posting pretty small elevation and slope maps to unmannedspaceflight.com, I was asked for larger versions…so here goes.
Followed by a derived slope map, made using the above elevation map. Again, small version below, larger version (~69 MB) here.
A word of caution – I have just used the HiRISE DEMs as they were provided. I haven’t normalised the DEMs (you can see the straight lines marking the boundaries) or georeferenced them (there might be slight offsets – I haven’t checked in detail). That said, they still look fantastic to me – thanks to everyone that put them together and put them out there, I know the work involved.
Finally, these are only exported maps of the actual data, which are just huge. Consider that each DEM is between 300-700 MB, so the final mosaic is something like just over 2 GB. I’ll try to think of ways to share that too, should anyone want to use it, although it won’t be through here unfortunately.
Posted on Jun 15, 2012
An easy one for my first project in the new flat. Spice jars seem to take up a lot of room for their individual small size, and normal spice racks are usually pretty rubbish-looking.
I quite liked the idea of magnetic spice racks, but balked at the idea of paying something like 40 quid for 8 jars. So I decided to make one myself, as it only involves a bit of super glue and a couple of screws.
In this case the sheet metal came from some scrap at work that I cut to size and drilled a couple of holes in that lined up with where there were already rawl plugs in the wall. I got the magnets online, unfortunately I didn’t record where from, but they were much much cheaper than anywhere else I could find on the high street. And in the end I ended up spending a small fortune on empty spice jars from habitat because, well, they looked nice.
Here is the underside of a couple of jars – the magnets are just superglued on, and as long as you don’t go lifting up a bin or something, they stay on just fine.
And here’s the final thing attached to the wall. still need to get another six jars to complete the OCD collection.
The best thing about it? it makes a really satisfying “tunk” when the magnets grab the metal and the jars flies out of your hand.