Tuesday, November 21, 2006
Just as I'm leaving, things are warming up in the Inner Basin and Spirit is getting the chance to stretch a little and look at some of the rocks and soil targets around her. She's looking at the white soil the wheels churned up on the way to where she is now. The white soils usually mean some kind of salt, and that usually means involvement of water. We're also looking at a rock layer that protrudes from Low Ridge like a fin. You can floow it all along the ridge to the rover. We tried to get the rover to move to break a piece off, but the sandy area where we are prevented the rover from doing that. Next week, we hope to actually drive a couple of meters to a basaltic rock and do a nice campaign there, looking at the vesicles (holes caused by escaping gas) in the rock and a detailed chemical analysis to see if these kinds of rocks are related to Home Plate. Then, it'll be off to Home Plate itself, a tantalizing feature we only zipped past last fall.
Opportunity has begun circumnavigating Victoria Crater, and every day there's a new, breathtaking vista. The team hasn't yet decided how far to go or when to try to go into the crater, so it's difficult for me to leave now knowing Opportunity could dive in at any time!
While you're missing me on this blog, keep up on what the rovers are doing through Steve Squyres' mission update, sites by passionate amateurs: MartianSoil, Mars Rover Blog and MarsGeo, and of course, the latest images direct from Mars are easily accessible from the Exploratorium web pages.
For other burning questions about all things planetary, spend some time at Planetary Science Research Discoveries, a fantastic site with very readable articles about current science.
Happy Holidays, everyone, and see you in February!
"Riddle me this Science Girl: Does the moon have magnetic fields? I read somewhere that one problem with putting an outpost on the moon will be shielding astronauts from radiation. Is this true? I also read that future lunar missions would be longer than the Apollo program, but that they would not run into lunar night. Does being on the surface of the moon during lunar night bring about special problems for astronauts and jet setting planetary scientists? I hate to bring up the whole digging thing again, but what about putting in a subterranean bunker? I am just curious; after all, the new JB movie is out and "Moonraker" was one of my favorites! Are there natural caves on the moon? What about unnatural ones?"
The Moon doesn't have its own magnetic field like the Earth does. The Earth's magnetic field comes (very basically) from its spinning liquid core. No spinning liquid core in the Moon = no magnetic field. There are some rocks on the lunar surface that are magnetized though - these might have been magnetized by large, ancient impact events in some weird way of physics I won't even try to get into. Anyway, the upshot is that the Apollo astronauts were very lucky. They received low-level doses of radiation during their sorties, which is entirely recoverable, but by pure luck, did not encounter a solar flare that would have really dosed them. Now that we understand both the lunar radiation environment and the effects of radiation on humans better, you can bet there's a lot more work going into how to deal with this issue.
I have a great T-shirt that says, "I'm taking a lunar day off." Would be nice! A lunar day is a month long - the time it takes from full moon (which would be high noon if you stood on the near side) to full moon. So if you're on the surface, you've got pretty much 2 weeks of sunlight and 2 weeks of darkness. On the Earth, our atmosphere does a lot to keep our temperatures even. Think of cloudy nights that are warmer than clear nights, or the fact that when you're in the desert, the days can be very hot but the nights a lot colder because of the clear dry air. On the Moon, there's no atmosphere, so you've got the sun beating down on you during the day (surface temperature +100C) and absolute darkness at night (surface temperature -150C). So whether you plan your surface sortie during the day or the night, you have some extreme temperatures to deal with. It would be extra difficult to try to plan for both extremes during a single sortie.
What can you do to protect against both radiation and temperature extremes? A subsurface habitat will have a constant temperature equal to the Moon's mean surface temperature (-23°C) and protect against radiation and solar flares. People have speculated on how to construct these kinds of things for decades, and some people want to build habitats in lava tubes, the only kind of natural cave on the Moon. But don't expect to see them anytime soon. Excavating and building subsurface modules are the kinds of incredibly expensive architechture you'd be looking at for permanent bases, not for sorties like we're currently planning.
Monday, November 06, 2006
Another part of the comment is: "We could slowly develop mining on the moon using the iron and ore to build and launch future space missions." Well, yes and no. In-situ resource utilization (ISRU) on the Moon is a hot topic and many people are working in this area - they even holdan ISRU conference every year. One of the obvious ISRU uses is, of course, to support astronauts, bases, and continued missions. But, the Moon's resources are not like the Earth's. Here on Earth, many metals are concentrated in ore deposits. To make an ore deposit, you need a source, a transport mechanism, and a concentration mechanism or trap (hmmm, not unlike meteorites!). On Earth, by far the most common way to get these is by moving metal around in water, or less commonly, through igneous and metamorphic processes (for more, see the wiki on ore genesis). The Moon has been bone-dry since it formed and doesn't have plate tectonics, so both these major modes of ore formation are inoperable on the Moon, and there's no chance that we'll find metal deposits to mine. But, resources like oxygen and hydrogen do exist and may be able to be used to sustain humans and create rocket propellant. Read more about what the ISRU community is doing at the ISRU website.
Monday, October 30, 2006
To celebrate Sol1K, check out the awesome panoramas of Spirit's winter haven. If you have red-blue glasses, I highly recommend the red-blue anaglyph.
Red-blue-green: Why do some comet atmospheres glow green? The coma contains cyanogen (CN) and diatomic carbon (C2), which glow green when illuminated by sunlight (called "resonant fluorescence”) (from Science@NASA).
Some of the fundamental science that we can do at the moon is near and dear to me. We know that large impact craters are ubiquitous on planetary surfaces. One rather small crater on Earth, the Chicxulub crater in Mexico, was largely responsible for wreaking havoc with the Earth’s climate and food chain, triggering a mass extinction of many species on Earth, including the dinosaurs. When you look up at the Moon, the large dark patches are lava flows filling giant impact craters. These craters are 1000 km across and formed in collisions with thousands or millions of times as much energy as the collision that created Chicxulub. To an incoming asteroid or comet, the Earth and Moon appear as a system with a single center of gravity, so whatever hits the Moon has an equal or greater chance of hitting the Earth. So it’s logical that if the Moon experienced these huge collisions, the Earth did too. But where is the evidence on the Earth?
The largest craters on the Moon are very old (4 billion years or more) and they reside in a crust that is 4.5 billion years old. In contrast, the Earth recycles its surface all the time, through erosion, burial, mountain building and subduction. Very few rocks on the Earth are older than 3.5 billion years, and the oldest recognized rocks are a bit of outcrop in northwestern Canada at just about 4 billion years. There are certainly not enough rocks to recognize giant old impact craters at 4 billion years on the Earth. And yet, it was at this time that life was just getting started on Earth. If one medium-sized crater killed more than half the flourishing species in the Cretaceous, what would a hundred giant impacts do to primitive life on Earth?
Some of the outstanding questions about the effects on Earth have to do with how many impacts, how big, and how closely spaced in time. We can’t figure that out on the Earth, because we don’t have the rocks that recorded that information. But the Moon preserves all the evidence if we can just get there and look for it. Moon rocks tell us the timing of large impact events, when and how many, and can even tell us what made the impact, what kind of meteorite. And just like pieces of the Moon get knocked off onto the Earth, large impacts should knock pieces of the Earth onto the Moon, and we might be able to find some very ancient Earth rocks on the Moon (though they will be exceedingly hard to find).
Other way cool science at the Moon has to do with the Moon’s unique atmosphere, which is a combination of outgassing from the planet, solar wind interactions with the surface, and levitating dust; the environment at the lunar poles, where permanently-lit peaks might be good places for solar panels and permanently dark craters might act as cold traps that store volatiles like water; and deploying a network of monitoring stations that can measure moonquakes, the magnetic field, and heat flow from the Moon. It’s also neat to think about the opportunities for new robotic capabilities – with a round-trip communications time of less than 5 seconds, we’ll have a chance to explore as scientists on the Earth interacting with robots on the surface.
Friday, October 20, 2006
I swear again, I do not plant these questions, but I just put up a new web page a couple of weeks ago, on New Mexico Meteorites, because we get a lot of questions about how to go meteorite hunting. Basically, it takes a lot of patience and time, and you need to be super-careful about whose land you’re on. Other than that, anyone can hunt meteorites. They’re basically irregularly shaped rocks with a black fusion crust and are heavy and magnetic. Unfortunately, that description also fits an awful lot of terrestrial rocks, so check out my other web page on How to Identify a Meteorite, including some easy tests you can do at home. And no, ANSMET team members don’t need to be familiar with meteorites to find black rocks on the ice, but the ANSMET program is funded for scientific purposes by NASA and NSF, so meteorite scientists get first crack at being team members, and as you might guess, there’s no shortage of volunteers from our community, though the project has also taken teachers, writers, photographers and astronauts.
What do you do with a meteorite when you find it? There’s (usually) nothing sketchy about private meteorite hunters. There are lots of people willing to pay for meteorites and if you take the time and money to find one legitimately, you can sell it on the open market. Meteorite hunters and scientific institutions have historically formed a partnership that benefits both of them – scientific institutions will classify and certify the meteorite’s authenticity in return for 20g or 20% of the mass of the meteorite, whichever is smaller. This allows hunters to sell authentic meteorites and scientists to retain pieces for study. In recent years, however, there’s growing concern about private meteorite hunting and selling both from a scientific point of view (frequently, the piece in scientific hands is unrepresentative and we don’t have the money to buy more pieces to really understand the rock) and from an ethical point of view (many meteorites are smuggled out of developing countries in Africa and the Arabian Peninsula by bribing local militias).
I’ll be going down to Texas in a couple of weeks (with explicit, written permission from the landowner) to field test some new equipment we here at the IOM got for meteorite recovery efforts if someone calls us and says they saw a fall, which people often do because the southwestern skies are big and clear. Metal detectors are good at finding meteorites among terrestrial rocks, but can be a pain because they also pick up a lot of spent ammo, aluminum foil and cans, and smelter slag. We’re also bringing a quick chemical test for nickel, with which we’ve had mixed results in lab testing, and a magnetic susceptibility meter, which measures the percentage of magnetic metal in the rock and seems to do a good job of distinguishing meteorites from slag.
Wednesday, October 18, 2006
Heatshield Rock, now an official iron meteorite named Meridiani Planum
Barberton, one of many rocks left as a lag deposits among the sand dunes of Meridiani Planum, and possibly a stony meteorite
Zhong Shan and Allan Hills, probably iron meteorites on Low Ridge in Gusev Crater
Why do we go to Antarctica to get meteorites? Meteorites fall randomly over the whole Earth throughout time. But, if a meteorite falls in the ocean, or fell 10,000 years ago, it's unlikely anyone's ever going to find it now. Once a meteorite lands, the Earth's forces of water and biology start breaking it down. There are some places on the Earth that are good for finding meteorites when there is a mechanism for concentrating many years' worth of falls in one spot and storing them under very dry conditions. The hot deserts are good for this, where meteorites land among the sand dunes and then when the wind shifts and starts blowing sand away, the meteorites are exhumed. Antarctica is also a good place because meteorites that fall on the glaciers get entrained in the ice (which is actually a pretty dry environment because the ice is so cold it never melts) and carried along the conveyor belt of the glacier. When the glacier runs up against a mountain, the winds convert the ice directly into the vapor phase (like leaving ice cubes too long in your freezer) and the meteorites are left behind. The ANSMET program has recovered more than 25,000 meteorites, or 85% of the world’s meteorite collection.
Why do we study meteorites? The basis of geology is that rocks hold information about the formation and evolution of their parent planet. On the Earth, we can hike around, study rocks in the field, and bring them to the lab for detailed analysis. But we've only collected rocks from only one other planetary field site, the Moon. So meteorites are especially scientifically valuable because they are the only rocks we have from Mars and the asteroids. Even lunar meteorites come from places on the Moon where human have never been and never sampled, and have given us a whole new view of lunar rocks. Remote-sensing techniques, like the spectrometers on our rover friends, are good at what they do but are still a far cry from being able to pick up a rock, crack it open, and measure its isotopic composition to, say, 1% accuracy.
Here's lots more about the scientific importance of meteorites, along with details on how they are collected and curated.
What's an ANSMET season like? You can check out last year's team blog or Linda's PSRD article written after the 2002 season. And, of course, you should tune in to my ANSMET blog to find out this year!
Tuesday, October 17, 2006
Pallasites are very rare meteorites. They are basically big crystals of olivine (in gemstone form, olivine is known as peridot) embedded in iron-nickel metal. Besides being incredibly beautiful, they’re scientifically interesting, but it takes a step back to explain why, so bear with me. Like the Earth, many planets heated up when they formed and the materials separated out roughly by density. We see that today on Earth as the crust, mantle, and core. Mars has a similar structure, and so does the asteroid Vesta, and probably so did many other asteroids that have since been blown into pieces by collisions. Pieces that fall to earth of these exploded tiny planets are recognizable as pieces of otherworldly crusts (achondrites) and cores (iron meteorites). We don’t have any meteorites that are definitely mantle material, but the Earth’s mantle is made largely of olivine, and remote sensing of Vesta and the Moon show olivine-rich material in deep craters, so by analogy, we think that asteroid mantles are made of olivine too. Where would olivine mix with metal? At the core-mantle boundary. So pallasites are samples from the core-mantle boundary of asteroids, a relatively narrow zone and so therefore relatively rare.
This specific meteorite, the Brenham pallasite, is one that has gotten amateurs excited for years. Smaller pieces of this meteorite have been found in farmers’ fields all throughout the midwest. Traditionally, meteorites are found by stumbling across them by accident or by systematically sweeping an area by eye or with metal detectors. In the case of Brenham, people suspected there could be more pieces lurking below the surface, and last year, meteorite hunters found the biggest piece of Brenham using a metal detector. The piece described in today's news story was found by combining two pursuits: looking for more pieces of Brenham and validating a hand-carried ground-penetrating radar instrument (that’s the “new” part of the radar) to find local buried resources, like meteorites and water (read more about that in the more explanatory AP story). OK, maybe white gloves are overkill considering all the other organic stuff that’s been crawling over the meteorite, but the recovery party (in part from the curation staff at the Johnson Space Center) was following standard protocol for recovering meteorites, which includes trying not to transfer any human skin oils to the meteorite. While it may have been on Earth a long time, it probably hasn’t been touched by humans ever.
Honestly, I did not plant this question, but it allows me a very graceful segueway into my next planetary adventure: the Antarctic Search for Meteorites. More on that in my next installment!
Friday, October 13, 2006
The Mossbauer team is excited that we'll be using this chance to collect some fantastic Mossbauer integrations. The Mossbauer spectrometer works by exciting the sample with gamma rays and measuring the emmision and absorption response of the sample. The gamma ray energy on the rovers' Mossbauer spectrometer is tuned to iron, so that the response is a fingerprint of the iron-bearing minerals in the sample we're looking at. This is good because so much of Mars is iron-rich, so the Mossbauer mineralogy has been very useful. But, the Mossbauer source natually decays, and at more than 10 times its expected lifetime, the MB source is fairly weak. This means that to get a good signal-to-noise ratio, we need to leave the MB on a target for something like 48 hours to even get the major mineralogy. To tease out the fine details, it needs more time, and we're almost never able to give it that time before moving on - until now. Both rovers have more than 10 days of Mossbauer spectrometry planned over conjunction. Spirit is looking at her magnet, which has collected magnetic dust along its traverse, to look at what iron-bearing minerals make up the Martian dust from the atmosphere and the ground that gets kicked up by wind. Opportunity is looking at a patch of rock at Victoria crater and I'm super-excited to see what minerals it can find in the rock here!
While we're letting the rovers do their own thing during conjunction, their timers will roll over sol 1000! Since nobody expected them to live this long, much of their software was built to only accept 3-digit sols (up to 999). It's like Y2K for the rover - quick, buy some bottled water and duct tape! The ground and flight software engineers did a fabulous job of either fixing or working around this issue and testing it thoroughly, so we don't expect any problems. Still, I feel like when we next see our little friends, they'll have passed this major milestone.
Space exploration is difficult. Space exploration is risky. Space exploration is expensive. Every time a mission fails (because it is difficult), the public demands that the next mission not fail (become less risky) and therefore the price goes up (becomes more expensive). Remember that 90's NASA mantra, "Faster, better, cheaper?" The inside joke was that you could only choose two out of the three.
During the era of Apollo, Viking, and Voyager, space exploration was driven by political pressure, not by science. Each Viking lander cost $1 billion in the early 1970's. That's something like $5 billion in today's money. The Apollo program is estimated at about $100 billion in today's money. Even the Russian Luna rovers are estimated to have cost $1-2 billion each back then. Of course, we have developed more and better technology, bringing the cost of missions down, so using today's technology, a Viking mission might cost $1.5-2 billion. Current Mars Sample Return estimates run from $2 to 4 billion. The reality is that putting a huge drill rig on Mars is not able to happen in the curent climate, where space missions are seen as being driven by science, and society just doesn't think it needs that much science.
I'll accept criticism that NASA, like all big government agencies, spends a lot of its money on bureacracy and could really use more imagination. But even if you were able to somehow cut the costs in half, billion-dollar Mars missions driven by science, however supercool and fantastic science it is, are going to be nearly impossible to fund until society sees them as valuable to them. Let's make a cynical comparison here: the movie Titanic grossed 1.8 billion dollars. Yes, the world's people spent $1.8 BILLION to go see one darn movie. That's three Mars missions right there, for one single movie.
OK, end rant. No more politics. Back to science!!!
Tuesday, October 10, 2006
I think the consensus now is that there is a lot of evidence of liquid water in Mars' past, but we're still a little fuzzy on the exact details - when, how much, how long it lasted, and where it was. Orbital photos have long showed things that look like branching river valleys and more recently, the MOC camera has captured many images of gullies in craters that might be caused by seeping subsurface water. There's definitely ice in the subsurface now, and presumably if you dug or drilled, you'd be able to get to it - the Phoenix mission will try to do just this - but it's likely to be mixed with rock or dust like the Arctic tundra, not like a subsurface glacier.
One of the biggest contributions to the story is Opportunity's view of the rocks at Meridiani Planum. There's pretty convincing evidence that these rocks are sediments that were laid down by flowing water on the surface. But, the environment that formed the rocks is probably more analogous to a braided stream or wash in the desert southwest than the oceanic shelf off the East Coast. We don't know exactly when these rocks were made, but we do know that at that time, there was a lot of sulfur and oxygen at the surface, making the Martian environment pretty harsh, acidic and oxidizing - very unpleasant for life as we unerstand it. We're just now trying to come to more understanding of the acidic/sulfuric environments vs more "clement" environments with CRISM, a mapping spectrometer on the MRO orbiter, which will be able to pick out areas with sulfates (acidic, sulfurous weathering) and areas with things like clays that we think formed under more neutral and less sulfurous conditions.
But having said all that, remember that Mars is an entire planet. Think about it - is the Earth covered with water? Well, yes and no, sometimes it was in some places and sometimes in others, sometimes the water is liquid and sometimes it is ice. The rocks exposed in the Grand Canyon were laid down by a vast ocean 500 million years ago, but southern Utah is now a windy, barren desert. Underneath the Pacific Ocean, the rocks are formed by erupting magma and have only trace amounts of water in them. The Earth is geologically complex and has 4.5 billion years of history complicating it, but we've been living here and studying the world around us for tens of thousands of years. Mars is also geologically complex and also has 4.5 billion years of history, but we've been studying it only remotely and for only three decades. It's a long process, figuring out Mars, and science is about getting more and more little pieces that we integrate into our understanding, rather than sending one spacecraft and expecting it to tell us the conclusive story. But, of course, each of our little pieces comes with a price tag and so we need to make sure we wring all the science we can out of it and tell everyone what pieces we are finding!
Friday, October 06, 2006
Here's a link to the MRO Press Release that tells you more about the image.
So this is approximately where Opportunity is now, and will be for the next couple of weeks. Right now, Mars is opposite the Earth in their orbits - For every year that it takes Earth to go around the sun, it takes Mars about two. So sometimes, like last spring and in 2004, Mars and Earth are near the same points in their orbits and close together on the same side of the sun. That's when you can see Mars brightly shining in the night sky (and when you get those email hoaxes that Mars looks the same size as the Moon). In the off years, Mars is on the other side of its orbit from us, and the sun is in between our line of sight, called "solar conjunction" because Mars and the Sun appear to be close in the sky. When this happens, we can't communicate with spacecraft there and everyone takes a two-week break. Last time, the rovers took two weeks off too, but this year, we're radiating 15-day plans to them to continue to do science on their own!
Wednesday, September 27, 2006
I know you've all been waiting for it as eagerly as we have .... today we're planning our last, cautious bump to the rim of Victoria Crater! Check out the images of Opportunity's approach via her navigation cameras: Tuesday and Wednesday. Today we'll be planning out the campaign that we'll conduct at Victoria. Basically, Opportunity will start with some spectacular remote sensing, so look for that later this week. Then, the team will decide which direction to start circumnavigating Victoria. We're expecting some fantastic orbital imaging from the HiRISE camera onboard the Mars Reconnaissance Orbiter that will help guide the team's decisions on where to stop and hopefully, where to think about entering this beautiful crater! Stay tuned....
It was a real treat to have a fellow MER scientist, proto-Dr. Shawn Wright from ASU (below, with me at the crater edge), join us there to show us some of the remote sensing he did of the crater. Shawn came fresh off field work looking at potential craters in South America and though tired, he was enthusiastic about guiding us to his favortite locations around the crater. At several stops, we could easily trace cliff outcrops and correlate specific ejecta lobes with remote sensing imagery because of Meteor Crater's unique (and fortuitous) target material: discrete layers of red siltstone, yellow limestone, and sugary white sandtone.
Wednesday, September 13, 2006
Opportunity, being near the equator, has my perfect life - sunny and warm year-round. She continues to zip along toward Victoria Crater, whose ejecta blanket turned out to look a lot like the normal Meridiani plains - flat, hard, some sand drifts. On sol 929 Opportunity almost got a hole-in-one by driving 100.31 meters to the small crater Emma Dean, where we are trying to look at what the bedrock in the ejecta blanket is. We got our last good look at the "normal" Meridiani rock at Beagle Crater (yes, another shameless plug for a caption I wrote). It's a really spectacular mosaic - and - there's a super-cool quicktime window you can open and scroll around the panorama from the center. Sweet!
After Ries, Rob & I spent a couple of days in Krakow and western Poland checking out my family roots, then drove to Prague for the IAU meeting. It was a timely meeting to attend because it was where all the planet-definition discussion was heating up, culminating in the vote that redefined Pluto. I couldn't vote, because I'm not a member of the IAU, so don't send me hate email. Honestly, I didn't think it would fly, because at a contentious lunchtime forum during the week, the panel asked for an informal show of hands and the proposals were soundly rejected. Basically, everyone is upset at different aspects of the proposal so there was no consensus. It's far from over and don't be surprised when the IAU takes this up again in 3 years at their next meeting.
(You're wondering how I would have voted? We now understand that Pluto is the prototype of this belt of icy objects in the outer solar system - it's a new discovery and reflects our new understanding of the solar system, and *that's* exciting. How to codify it scientifically seems less of a problem than dealing with the "public outrage." I did a radio interview last week on the topic and one of the other guests says he knows someone who learned the planets *before* there was Pluto. I wonder what that was like, did people protest that now all the textbooks were obsolete and how could they be expected to come up with a new mnemonic? Crazy.)
In Zurich, at the Meteoritical Society meeting, I had a great time talking with some of our European APXS/MB colleagues including Christian Schroeder and Jutta Zipfel. We're all very excited that both rovers just uplinked a flight software update -an amazing thing to do so late in the mission - that includes some fantastic new capabilities for our little buddies. The most exciting thing for us IDD types is the ability to go-and-touch. Up til now, we need a full sol to approach a rock and downlink images from the hazard-avoidance cameras, then there's a human in the loop to assess the images and determine how safe it is to deploy and extend the arm out to touch a rock that we want to look at, then then next sol we uplink the touch command and can start taking data. Because of the vagaries of the planning process, this can actually take more than one sol sometimes. The new software will (hopefully) allow the rover to make an independent determination of a safe place to put the arm instruments and go and do it without us, saving us a sol (or more) of real time.
Also in Zurich, I found out to my surprise and infinite delight that the asteroid formerly known as 1981 EB28 is now officially 6816 Barbcohen! How cool is that! Read the UNM story about it here. It's only a tiny speck of a rock in the main belt, but this is where it was on Aug. 10, the day I found out!
You can see where it is any time by going here. Of course, Spirit and Opportunity already have theirs too!
Thursday, July 27, 2006
This summer, I've been focusing on trying to understand Martian impact glass. A couple of the rock types in the Columbia Hills appear to have a glass component in some of the infrared spectra. But, when glassy rocks form on the Earth, they are very easily altered and weathered away. So, it's a little bit of a paradox as to why ancient Martian rock that look weathered still have glass in them. Plus, we don't really understand what the glass is or how much is there. Fortunately for us, we have a couple of examples of Martian glass here on Earth contained in the Martian meteorites. It may not be exactly the same glass, or even formed the same way, but I can do a lot more with a sample in my lab than the rovers can do on the surface. So, I'm trying to characterize the meteorite glass using various lab methods and compare it with our rock data from the mission. I'll be presenting my progress so far at two meetings in August: the Meteoritical Society meeting in Zurich and the International Astronomical Union in Prague. Yes, it's a rough life I lead this summer :)
Thursday, June 29, 2006
It was with that comment fresh in my mind that I was asked to write a caption for this week's public image release for Spirit, which has been working on this really interesting rock. We had to do a little bit of work to strike the right balance between getting the interesting part to the public while still being cautious because the results come out so fast that we scientists don't always have time to keep up with the data before moving on, and so our detailed science can lag behind the rovers' discoveries. The chemical and mineralogical data, in particular, take a lot of time and attention to be sure the calibrations and interpretations are the best we can do. In the case of Halley this week, I was pleased that we were able to give some specifics that the team agrees on.
Sunday, June 18, 2006
But speaking of Pancam, last week I found myself in upstate NY for some family things and took a slight detour up to Ithaca for a couple of hours. I spent part of Opportunity's planning day with the Pancam crew at Cornell, which was fantastic (in that inner geeky way). I met several of the payload uplink people, with whom I've interacted on the telecon line many times, and got to see where the polycon shows them hard at work. I also was able to ask lots of questions about compression algorithms and other super geeky things I wonder about during the planning process. I don't think I'll be an expert remote senser anytime soon but the more I am able to actively interact, the more things soak in eventually.
Finally, my idol Steve Squyres was on the Colbert Report on Comedy Central last week; you can see the video clip there or download the entire 06/07/07 episode from iTunes. The more Steve does on this mission the more in awe of him I am and the more nervous I get around him! But Stephen Colbert does a great interview - he had a similar idea as mine - to drive the two rovers toward each other. OK, my idea was to have Robot Wars (verrrrrry sloooooowly) and his was to mate them and create a race of robot overlords, whatever. Each rover only has to travel 5336 km to meet in the middle; Spirit has driven 6.9 km already and Opportunity 8.1 km. At an average speed of 3.8 km/year, it'll only take another 1400 years or so. Stay tuned!
Friday, June 02, 2006
Friday, May 26, 2006
Victoria punched a deeper hole into the Meridiani Planum surface than the last big crater Opportunity visited, Endurance crater. Endurance crater was where we got to check out Burns Cliff, a fantastically well-preserved set of sedimentary layers in the inside crater wall that showed crossbedding, evaporite mineral casts, and the little hematite blueberries. Craters are nature's roadcuts, the way these little mechanical geologists will be able to check out what's underneath the surface of the plains, and we're all hoping that the inside walls of Victoria show us more wonders.
Right now, Opportunity is about to roll up onto Victoria's ejecta blanket, which is the apron of material that was thrown out of the crater and rained down around it. When craters form, a lot of stuff gets thrown out from a depth roughly as much as the drater diameter. As the rocks deform and fail with the crater shock, the final crater is much shallower, only about a tenth as deep as the diameter. So, the rocks in the ejecta blanket come from much deeper down than the rocks at the bottom of the crater now. If you want to look for the deepest rocks, you look at the edges of the ejecta, which is what's next on our journey. We're stopping nearly every weekend to check out our surroundings to see if anything is different yet.
It's a little ironic - we're now interested in changes in the rocks but all we see are really large expanses of the same Meridiani Planum bedrock. One of the science team members remarked that last year, huge expanses of crossbedded bedrock would have been nirvana for this rover. But the scientists were so good at eking out the geologic history from what small outcrops they had that now we are just enjoying this area for the ease of driving over lots of flat material.
Tuesday, May 02, 2006
In terrestrial analog news, I will be heading to the Ries Crater in Nordlingen, Germany, after the Meteoritical Society meeting this summer. Ries is a well-preserved 24-km diameter, 15 Ma crater with post-impact lacustrine layers inside and fantastic outcrops of ejecta. The Ries ejecta may be a good analog to Martian double-layered ejecta deposits. There is an upper ejecta layer (suevite) which is a mix of deep material and impact melt, overlying a lower layer (the Bunte breccia) which is an interesting unit formed when the first (shallow) ejecta was ballistically emplaced and churned up the substrate, mobilizing it and causing a radial flow. It is rumored there are distal parts of the Bunte breccia containing crossbeds and lapilli that may be potentially interesting to compare with proposed origins of Meridiani and/or layers in the Inner Basin. Cool!
Monday, April 24, 2006
Spirit is definitely nestling down for a long winter in her present location. Unfortunately for me, there's no good rocks right in front of the rover, so my grand plans for multi-rock analysis campaigns will have to wait until after the southern Martan winter solstice (August 8). The soil and remote sensing people are kicking into high gear for the first part of winter and have some really cool plans for looking at different levels in the soil and acquiring the McMurdo Pan, a grand 13-filter panorama of everything around us. Opportunity is still zipping along, less than 1500 m to go to Victoria crater!
So, while I am supporting operations, I'm trying to dig into some data analysis, including multivariate analysis. I took linear algebra in college as an elective because I am such a geek. It was one of the few classes where I succumbed to the whining refrain, "When will I ever use this in the real world?" Well, 15 years later, it's come round to haunt me with whispers of eigenvectors.....
Friday, April 07, 2006
Here on Earth, we had a fantastic turnout for the MER sessions at the Lunar and Planetary Science Conference, where the team updated everyone on the current science and other members of the community got to offer their own interpretations. Always lively, sometimes contentious, never boring. It's an exciting time to be looking at this data! I presented my poster on my ejecta calculations - how much ejecta from far-away terrains should we expect to find at the MER landing sites? I'll give you a clue: not much. But you can see the whole paper here. It's my first single-author paper and it was published on my birthday this year!
Up on Mars, Spirit is dragging a wheel. It's the right front wheel, the one that went gimpy early in the mission. At this point, it is steerable but not driveable and so it's just dragging behind us. In principle, that's fine and the rover is totally ok driving with 5 wheels. In practice, we got terribly bogged down in some soft, sandy soils and had some real scary days where the rover wheels dug in and we watched our power sink lower and lower. We re-evaluated our plans to get to north-facing slopes and decided to retreat back the way we came to better ground.
We chose a Winter Haven along Low Ridge, a small feature possibly connected to Home Plate, with nice slopes and lots of rocks. We're now developing plans for what to do there as Spirit waits out the winter. I think it's going to be a really exciting time because we will finally have time to sit in one place and do some detailed analyses of rocks and soils, so I'm actually very much looking forward to the winter, despite the scary power numbers!
On the other side of the planet, things are looking zippy - literally. Being nearer the equator and dust-free, Opportunity continues to have a favorable power situation even into the wintertime and is making amazing mileage along dune troughs and outcrop rock. We're only 2 crater radii away now from this humongous crater, Victoria, which is Opportunity's destination. It's old and eroded but probably dug pretty deeply into Meridiani Planum, so it should be super interesting when we arrive.
Tuesday, March 07, 2006
LPSC is our big planetary science conference, held annually near the Johnson Space Center in Houston. It started as the Lunar Science Conference back in the day, then expanded to become the Lunar and Planetary Science Conference. For the last couple of years it might as well have been the Martian and Other Planetary Science Conference. There's at least one Mars session every slot, and sometimes Mars goes head-to-head with itself. I'm looking forward to seeing what everyone has been up to!
Friday, March 03, 2006
For the first time since I joined the team, I've been way too busy for the last three weeks with other aspects of my job to really keep up on what one rover is doing, much less both of them. It's much more clear to me now why they need new, enthusiastic people to come in and put the time into the rovers. I was glad to have a specific job to do this week that forces me to look at the data coming in and participate in the process. It's easy to get overwhelmed after missing even a couple of days!
Monday, February 13, 2006
Both the APXS and the MB were designed and developed by German teams as contributions to the MER mission, and they are led by the Payload Element Lead scientists in other countries. They are the ones who know the real ins and outs of these instruments. But, in the current mode of remote operations, two people at JSC know an awful lot about the day-to-day operation of the instruments, and Houston is a lot easier to get to than Germany.
These three days were really rewarding for me. Days like that are the ones that keep me going through the slump months. It was the busiest couple of days on both rovers that we could have asked for, as both were using their arm instruments on interesting outcrops. I got to see lots of friends and meet new colleagues, learn something really interesting that only a few people in the world can do, feel confident that I can do it well, and talk about the science with a collegial bunch of planetary scientists. As an extra bonus, while there, I also got to see the Stardust samples making tracks through their aerogel collectors, just a few weeks after their return from Comet Wild/2.
Friday, February 03, 2006
On my commute home every evening, I head up La Bajada hill, an abrupt fault face capped with spectacular columnarly jointed basalts of the Caja del Rio field, where I live. It's usually getting on dark when I creep up the hill, but this week I happened home early and saw my passage through the tumbling basalt boulders, steep arroyos, and deep red soils. I really paid attention to the illumination, the relationships between boulders and layers, to what I saw and what my brain filled in as "normal." It was one of those great moments when I'm so happy with my own brain. Then, later in the evening, it got dark and there was Mars itself, a shining orange point.
Monday, January 30, 2006
Gusev Rocks Solidified from Lava
In recent weeks, as NASA's Mars Exploration Rover Spirit has driven through the basin south of "Husband Hill," it has been traversing mainly sand and dune deposits. This week, though, Spirit has been maneuvering along the edge of an arc-shaped feature called "Lorre Ridge" and has encountered some spectacular examples of basaltic rocks with striking textures. This panoramic camera (Pancam) image shows a group of boulders informally named "FuYi." These basaltic rocks were formed by volcanic processes and may be a primary constituent of Lorre Ridge and other interesting landforms in the basin.
Spirit first encountered basalts at its landing site two years ago, on a vast plain covered with solidified lava that appeared to have flowed across Gusev Crater. Later, basaltic rocks became rare as Spirit climbed Husband Hill. The basaltic rocks that Spirit is now seeing are interesting because they exhibit many small holes or vesicles, similar to some kinds of volcanic rocks on Earth. Vesicular rocks form when gas bubbles are trapped in lava flows and the rock solidifies around the bubbles. When the gas escapes, it leaves holes in the rock. The quantity of gas bubbles in rocks on Husband Hill varies considerably; some rocks have none and some, such as several here at FuYi, are downright frothy.
The change in textures and the location of the basalts may be signs that Spirit is driving along the edge of a lava flow. This lava may be the same as the basalt blanketing the plains of Spirit's landing site, or it may be different. The large size and frothy nature of the boulders around Lorre Ridge might indicate that eruptions once took place at the edge of the lava flow, where the lava interacted with the rocks of the basin floor. Scientists hope to learn more as Spirit continues to investigate these rocks.
As Earth approaches the Chinese New Year (The Year of the Dog), the Athena science team decided to use nicknames representing Chinese culture and geography to identify rocks and features investigated by Spirit during the Chinese New Year celebration period. In ancient Chinese myth, FuYi was the first great emperor and lived in the east. He explained the theory of "Yin" and "Yang" to his people, invented the net to catch fish, was the first to use fire to cook food, and invented a musical instrument known as the "Se" to accompany his peoples' songs and dances. Other rocks and features are being informally named for Chinese gods, warriors, inventors, and scientists, as well as rivers, lakes, and mountains.
Friday, January 27, 2006
On the Spirit side, I've been dabbling in speculative volcanology, a new discipline I could really get into. Basically, we're seeing lots of volcanic rocks and the orbital maps seem to show lava flows as well. But, we haven't gotten any decisive data yet, and I'm not a volcanologist. It has been fun (for me, anyway) to learn about various modes of volcanism from my officemate and from other members of the team who are willing to listen to my latest crazy idea!
Wednesday, January 18, 2006
The first two days, I shadowed the Keeper of the Plan, a job I hope to start in a month or two. This job is to keep track of all the science activities people request for the day. Like Doc, which I’m doing right now (right now!), it’s a good way to keep my interest in the day-to-day activities of the rovers. It’s like the difference between taking a class for credit or audit – when I audit a class, it’s more difficult for me to find the time to devote to it than if there’s something riding on it. During the first part of the week, I spent the mornings in the science meetings and the afternoons with the planners and learned more about the process. Steve Squyres himself was there as chair, so it was wonderful to sit through the process with him and pick up bits of knowledge.
While we were all at JPL, we had some very crowded planning meetings and happened across a white sand patch that turned out to be packed with sulfur. My roommate Aileen and I were up very early in the mornings to get in and help with picking targets! I know things are busy when they cut into my precious sleep time.
The last three days were spent with the entire Athena team, gathered in the auditorium to talk science. I was very intimidated at first, had to introduce myself to everyone and felt like I should justify my addition to the team. But everyone was super, very welcoming and interested. I gave a talk on my interests that went ok - I wanted it to be fabulous, but it was just ok. I couldn’t think of anything funny to put in it so just gave it straight. One thing I resolved on the second day was to speak up when I had a question or comment instead of asking my neighbor quietly. Surprisingly to me, I did that 5 times! Ultimately, the talks and the time to meet with people were great for me to see what we are still struggling with, what new ideas can be generated, and what I have the tools to jump into.
Sunday, January 08, 2006
(With apologies to Sir Mix-a-Lot and to you, dear reader)
I like Big Basins and I cannot lie
You scientists can’t deny
That when a crater formed 4 billion years ago
And that’s where the spacecraft goes
You’ll get sprung! Wanna land your stuff
Cause you’ll notice that basin’s stuffed
With climate records in the sediments
And ejecta in the pediments
Ooh ring of mountains
Of knowledge it’s a fountain
Push that record later, later
Cause this ain’t no average crater
Tuesday, January 03, 2006
This week I have my first shift as a science theme group lead. The operations of this mission were carefully structured by Steve and his management along science lines where the team thinks of the rovers as integrated instrument packages. That may sound mundane, but in the world of missions, frequently instrument teams find themselves pitted against each other for time and power resources. The science-based approach has worked well on this mission and encourages us all to work together toward our common goals of exploration and discovery.
The science groups are centered around geology, mineralogy & geochemistry, atmospheres, and physical properties. Scientists from each group are responsible for ensuring that activities get planned that support these areas of Martian science. My interests are mainly in geochemistry and mineralogy, so I am in that science group, and this week I am the lead advocate for the group. In practice, this isn't a lot more time than I'd normally put into looking through the data and taking an interest in what's coming up, but there are a couple of systematic observations I'm responsible for suggesting, and of course, I'm a little nervous about not making a fool of myself :)
Most of the MER scientists and engineers got a well-deserved break over the holidays. But the rovers wouldn’t know what to do with a day off. They get so much new energy every morning, like my cat! So a few people were busy right before both holiday weekends putting together multiple 3-day plans to keep the rovers busy while we went home to families and celebrations. The University where I work is closed all week between the holidays, and it’s a pleasant break to not have to drive the hour+ to get there, so I was happy to bring my speakerphone and laptop home for the week and keep up remotely.
I get to the Starbucks closest to our house (it’s about a 15-minute drive into town) for an hour in the morning while Rob’s still asleep and just download what’s available – images, documents, everything. Then I bring it home and sort through it, make mosaics and false-color views, read what actually got accomplished in the last plan, see if I can spot interesting targets where we are, make sure I understand where we’re going and what people think we should do. Then, I call the telecon line from home and participate in the science planning process for the day. It’s total about 3.5 hours for the day if I want to really get into it. There are summaries and other ways to stay abreast of developments on a weekly basis, like this great web site at JPL that I use to check on Opportunity while I am focused on Spirit.
But for the rest of the week, I did take vacation. Rob also had the entire week off and my brother came into town for Christmas and the first part of the week. He’s super fun and we had a fabulous 5 days. Rob and I had big plans to be tourists in our own state for the rest of the week, but those all got canceled when we both got sick and spent the next 5 days cooped up at home sleeping, reading (me), and playing computer games (Rob). Objectively, that’s probably the vacation we needed.
We had a team meeting to decide whether we wanted to spend a couple of weeks heading for one of these dunefields near us, called El Dorado. There are several members of the team interested in aeolian processes (how sand moves) and physical properties of the martian surface (which might be very different in fresh dunes vs old soil), who are eager to go. But what convinced me to get on board was the fact that El Dorado is visible from several orbiting spacecraft. It’s an exceptional opportunity to collect real Martian ground-truth to help interpret orbital data, a topic about which I’ve been known to kvetch.
So down through the rocky, desolate Indian country Spirit went, trading among the Apaches and Comanches, heading southwest on the path to El Dorado. The rover planners outdid themselves again, with some lengthy beauties of drives topped off with a scuff right on a dune face. And here we'll spend a long holiday weekend with the arm out, using all our instruments in chorus on the black sands of El Dorado.