Meanwhile at Europa, The Plot Thickens

 Divide and Conquer!
A concept for cutting JEO into two pieces brings an Europan Mission back towards the realm of the possible!

VK over at futureplanets reports on two mission proposals to Europa that were delivered to the recent OPAG meeting. The upshot is that by taking a page from the Mars Exploration Program, the outer planets folks have found that they can divide and conquer to explore. By cutting up the science goals and objectives of the US part of EJSM (known as JEO) into two missions - an Europan Orbiter and a Fly-by vehicle - it is possible to reduce the cost of the total missions by over $700 million. More importantly, it divides the program into much more manageable chunks, each of which costs less than $2 billion.

Each according to his gifts: Analogues, A Canadian Contribution

This beautiful image taken by U of T's Tim Barfoot shows the ROC-6 Rover that will be used to simulate a Lunar Rover this summer as part of an Analogue Mission. It is shown here at one of the CSA's 10 Analogue Sites: Lake Orbiter, Devon Island.

How can Canada best contribute to Planetary Science and the development of Space Missions? Should we launch our own superior spacecraft? Develop our own cadre of scintilating supporting scientists? Engineer the finest quality instruments? Well, we do currently do all of these things. But while we do posess high quality in each domain and make valuable contributions to missions, it is unlikely that we will become the largest source of either.

However, there is one domain in which we have a distinct advantage. Ours is a large country with many different environments. These provide excellent places to check-out landed spacecraft equipment and develop techniques to command them. If this testing is done in what we call a "flight-like" manner (that is to say that we force upon ourselves the constraints which would exist were the mission actually occuring on another planet) then we have a special name for the exercise: an Analog Mission.

Such a Mission should have all the necessary simulated pieces in place to mirror an actual mission. These include a realistic instrument platform (i.e. a lander, rover or other spacecraft simulator), realistic instrumentation, realistic communications and a remote mission operations team which works on a schedule that is itself suitably "flight-like."

Conversations at the LPSC: Dr. Michael Bland

Dr. Michael Bland surveys the landscape
in this photograph taken in 2006 in Death Valley, CA by Catherine Neish.

Tonight we move a little bit away from the Decadal survey on Astronomy.fm 's Live from York U. While the topic still comes up in reference to EJSM/JEO I focused on speaking with Dr. Michael Bland about his work studying the icy satellites of Jupiter and Saturn. Mike is a tectonics expert who looks at the geophysics and geomorphology of surface features to glean information about the interiors of these satellites. His specialty is the Jovian moon Ganymede, the largest of all satellites in our solar system and really a world in its own right with a diameter almost 400km larger than that of Mercury. Ganymede may not be the first body you think of when tectonic features come to mind. Certainly, the cracks formed on the surface by internal stresses are less dramatic than they are on Europa and less explosive than on Enceladus. But the terrain is more varied and perhaps less understood on this world.

Hope and a Call to Action: Planetary Decadal Survey Released

Steve Squyres (left) and Jim Green (right) answer questions Monday Night at LPSC following the unveiling of the Planetary Decadal survey. Image is a screen capture from the live feed recap (I attended in person).

I can remember when I first met Steve Squyres. It was way back in May of 2004 when I was unbelievably green and doing a two week internship on MER at the behest of my advisor, Peter Smith. I was in the microscopic imager room in Pasadena with Nicole Spanovich (now at JPL) and he stuck his head in to see what was happening. Nicole introduced us and I remember him saying hello to me. I don't remember what I said in return, but I do recall that before I could think of something clever to say, he was off again to the next instrument room.

LPSC Notebook: Trouble Ahead

An artist's conception of a submarine exploring the Europan Ocean is shown in this NASA-JPL illustration. Currently, I'm not even 30 and the chances that I will see pictures like this in my lifetime looks like they will decrease tomorrow once the planetary decadal survey is released.

Something's in the air here in the Woodlands, and it's not pleasant. I certainly got my week off to a bad start with some hotel snafus here at the 42nd LPSC that have seen me in a different room each night. I must also report that I'm a bit disappointed in the location. Basically, we're located at a pedestrian-unfriendly high-end strip mall, though I do understand that this location is cheaper and more accessible for many. Oh, and now this: leaked details of Steve Squyres' Planetary Decadal Survey as described by Space News.

Dr. Britney Schmidt (Conversations at the DPS, profile 4)

Dr. Britney Schmidt poses in front of a combination of rocky and icy material, sadly not at Death Valley.

Britney Schmidt is a rising star of planetary science, as many of us have known for a while now. I first encountered her in Bob Brown's lab at LPL where she worked as an undergraduate. At the time, she was performing lab experiments on isotopic systems in sublimating ices, and cutting her space mission baby teeth on Cassini. I also had the opportunity to participate in a JPL Team-X exercise (aka Planetary Science Summer School) with her in 2005. While we butted heads a bit on that project, we gained a mutual respect for one another (or so I'd like to think) and our group put out a solid proposal for an Europan Orbiter.

Britney would later follow-up on what is perhaps the most critical part for such a spacecraft, an ice-penetrating radar, which is something she looks into in her current position as a postdoc at University of Texas at Austin. In her spare time she is also the director of the Education and Public Outreach effort for the Dawn Mission. Dawn will be the first robotic spacecraft to enter into the gravitational well of a body as an orbiter, break orbit and go on to another body, in this case two of the largest main-belt asteroids Vesta and Ceres.

This expertise with asteroids is something that Britney picked up during her doctoral work at the University of California, Los Angeles. Like me, she is a bit of a jack of all trades with experience running lab experiments, doing theory and observing other planets in their natural environments. In particular, she has used the Hubble Space Telescope to look at asteroids, revealing that there are examples which bear the spectral signs of water ice on their surfaces. I find it facinating that the more we look at comets, the more they look like asteroids (the flyby of comet Hartley-2 showed a very "asteroidal-like" body) and similarly, the more we look at asteroids, the more some of these look like comets. Britney's work was published in Science last year and won her acclaim. At the time of her interview, I hadn't seen her in person for over five years and it was good to catch up.

Britney's interview runs tonight (Monday) at 8:00 PM EST over on Astronomy.fm's "Live at York U" program. Unlike for the previous interviews, I am off tonight - but not to worry, Jesse and Paul will keep you entertained with the latest news from the Observatory and commentary on what Britney has to say, so feel free to pop by yorkobservatory.com and ask questions in the OPV chat room!

DPS Notebook, Odds and Ends

Still emptying the DPS journal folks, one more to go after this one, but that one won't be about DPS per se, just general musings on the profession, conferences, etc. (something I wrote at 4AM on the plane home, so I've yet to decide whether to throw it up).

The first thing to mention is that I was lucky enough to get a total of six interviews with early career folks at the DPS and I feel they went rather well. After speaking with my colleagues at "Live at York U" over on Astronomy.fm, we have come to a decision regarding the schedule. Things kick off with a little introduction from me on October 18th, including some clips from talks by Ray Arvidson, Bob Pappalardo, Steve Squyres and Jim Green, then we get into the meat of things:

October 25th - Dr. Jason Barnes (Idaho)

November 1st - Dr. Catherine Neish (Johns Hopkins/NASA-APL)

November 8th - Dr. David Minton (SwRI/Purdue)

November 15th - Dr. Britany Schmidt (Texas)

November 22nd - Dr. David Choi (Arizona)

November 29th - Dr. Jonathan Fortney (Santa Cruz)

Note that all interviews will run over on Astronomy.fm at 8PM Eastern, 5PM Pacific. I believe that we will be shifting with the clocks when that happens, so for listeners in Arizona, note that time change. I am also happy to report that all the interviews will run in complete form, and have only been slightly cut. So look for 20-30 mins for the interviews.

I'm planning on doing a little blurb about each of the subjects on the day their interview airs. But I will reveal this much now: in addition to planetary science we all share a connection to the Lunar and Planetary Laboratory at the University of Arizona. Some of us are still there (Choi) and most of us got our PhD's there (exception: Schmidt [UCLA]). In part I picked these people because I was familiar with them, even if I don't know them that well personally. But it is a testament to the program at LPL that I didn't have to look outside to find a wide range of expertise and planetary targets for study. We will be spanning the entire solar system both in time from its formation to the present day, and from the Earth, through the Asteroids, Jupiter, Europa, Saturn, Titan, the Ice Giants, the Kuiper belt and on to Extrasolar Planetary Systems.

Are you a Planetary Scientists and would like to be the subject of a future interview? Drop me a line in the comments! If you're located in the Greater Toronto Area or will be at next March's LPSC, we can arrange something taped, otherwise we can do a live interview. Either way we'd love to hear from you!

Other interesting tidbits (based on my #DPS2010 posts):

(1) Mars just keeps getting more warm and wet in the past - we've found exposures of the missing carbonates exposed by impact craters all over the place. The absence of carbonates was a major mystery for a long time. However, it seems that much in the same way that most of the water-altered minerals at Gusev were buried by later deposits, the carbonates are not absent, merely covered up! I was less impressed by the atmospheric modelling teams who used today's martian terrain and obliquity to describe the movement of volatiles 4 billion years in the past. While it's true that we don't know what that Mars would have looked like, it seems clear that Tharsis, at least, would not have existed. Since, in the current day, Tharsis is a major obstacle for a moving air mass and causes a great deal of atmospheric condensation through orographic cloud formation it should not be present in past models. Still, the authors did point out that it is difficult to support liquid on Mars with the faint young sun, even if you assume a very thick 5 Bar CO2 atmosphere.

(2) A consensus is emerging over lunar swirls - as someone who has done some geomorphology, I'm a sucker for an interestingly shaped surface feature. The lunar swirls have been a mystery for a long time since they were first seen in the 1960s. In an impressive series of talks in the lunar session, observations made by LRO placed brick after brick in the foundation that these are features in which variations frozen into mare lavas have been emphasized by differential space weathering. The anomalous magnetization of these features show that they deflect the solar wind. Thus, in addition to their differing magnetization they show differing albedos and a lack of solar-H implantation (so no hydrated water). However, Radar backscatter shows no difference in roughness, implying that the swirls are only skin deep (less than 15cm)!

(3) The disappearing exoplanets announcement - a great deal of excitement surrounded a talk called "Title Embargoed." After all, if we couldn't know the title ahead of time, it must have been a pretty big discovery! However, through the magic of delayed peer review, the presenters took to the stage only to announce that Nature would not permit them to speak about the work. Speculation as to what was to be reported was rampant, as were thoughts as to why the reviewers might be drawing out the process. In this highly competitive field, it could be that the reviewers are stalling until they can replicate the result. Or it could be that the discovery is itself uncertain and the authors are having difficulty satisfying the reviewers that their discovery is genuine, above the error bounds of their measurement. For an example, just take a look at the discovery (or not) of an earth-sized planet just this past week.

(4) Titan surface geology outpaces our wildest hopes - data from Radar and VIMS were presented in which wave height in the Titanian lakes was constrained both from specular glinting and backscatter. As well, the controversial proposition that the equatorial "coffee ground" sand dunes show interspersed liquid hydrocarbon seepage was debated.

(5) Faster computers make dynamical calculations better - some of the major problems in solar system formation are beginning to sort themselves out, in particular the long-standing puzzle of why Mars is so small. It seems that the solution may be that as the Giant Planets migrated inward then outward, they created a sharp edge to the disc of planetessimals which formed the inner planets. As well, the outward migration would have scattered a great deal of icy material in past the solar system's snow line, enhancing the amount of water delivered to the terrestrial planets. This is troubling from an astrobiological point of view, since to make this situation work you need two large gas giants which form early and in just the right places and then evolve until they hit a resonance with one another many millions of years down the road. How common is that type of formation? At the very least it adds another term to the drake equation.

Do we need “All of the Planets, All of the Time”?

A colleague of mine with whom I have written a paper or two, Andrew Schuerger, announced at LPSC one year the existence of life on Mars. While it was a little tongue-in-cheek, his point contained an essential truth: that given the decontamination procedures in use, viable microbial life had almost certainly been transported to Mars on the inside of spacecraft. This was not idle speculation, nor was it entirely novel; cameras retrieved by the Apollo astronauts from the Ranger Lunar Landers still carried culturable bacteria after years of exposure to vacuum and radiation on the surface of the moon.

Even so, this doesn’t mean that we can expect to see carpets of green radiating out from our landed spacecraft any time soon. In fact, what organism are present are most likely in the form of dormant and hardened spores since Mars remains a pretty harsh place for even bacteria to grow. Further, anything viable on the exterior of a Martian spacecraft or on the surface would be killed within at most a few months of exposure to UV, depending on where it fell (you can take a look at http://adsabs.harvard.edu/abs/2007Icar..192..417M for more details on these extreme cases).

This begs the question as to whether procedures used to decontaminate spacecraft and prevent forward contamination (not to be confused with reverse contamination by any extraterrestrial microbes, the type popularized by movies like the Andromeda Strain), collectively known as planetary protection and administered out of the Planetary Protection office of NASA in the United States, are really necessary.

One reason for wanting extra stringent sterilization is scientific. You need to have a very clean spacecraft to prevent any sensitive life or organic-detection equipment from inadvertently showing a false positive. To prevent this, severe decontamination measures are often taken. For instance, the Robotic Arm on the Phoenix Lander was enshrouded in a “bio-barrier” until after landing. But as we didn’t want to come to Mars to “discover” terrestrial organics on the scoop, this was an important precaution.

The specific level of sterility required varies by destination. The Robotic Arm employed by Phoenix needed to be as clean as it was as a result of its potential contact with the ice table in a region where life or its traces were possible. By international agreement, COSPAR has designated four levels of these regions which require progressively more stringent planetary protection measures (category five relates to reverse contamination http://cosparhq.cnes.fr/Scistr/Pppolicy.htm). The level of protection ranges from none, for a level one body like the moon to full sterilization for access to so-called special regions of Mars or Europa, the only two level four bodies in the solar system.

There are a few locations that may come as a surprise. Even orbiters of Mars are designated as level three, while a Venusian lander is rated at level one, mainly because there is nothing we can do to a spacecraft on Earth that is as destructive as what the venusian environment will do in-situ.

Either way, exploring a special region can be a costly or even a prohibitive burden on any space mission. Sterilization for the Viking Mission cost almost US$320 million, adjusted for inflation, or about 70% of the cost of an entire discovery-class mission.

More significant is the potential impact on mission operations. Often there are financial pressures which require reducing the functionality of hardware, a process known as descoping. This is true of nearly any mission, large or small. Cassini, a burly flagship, had its scan platforms eliminated while Phoenix, a bare-bones Scout, saw its Direct-To-Earth antenna and descent imager descoped. Thus, as a significant expense, one can cut costs dramatically by avoiding any region that requires special procedures altogether.

This is having a large impact on our exploration of Mars. Both ESA’s Exo-Mars and NASA’s Mars Science Lab, each a flagship-class mission, are avoiding special regions to pare back costs.

As well, it is arguable that an opportunity to study Europa might have been lost by the requirement of disposing of the Galileo Spacecraft in Jupiter’s atmosphere and not having it strike Europa. This could have been observed from the ground, or timed to coincide with the passage of the New Horizons spacecraft, which passed through the Jovian system on a gravity assist in February, 2007. The resulting plume could have told us a great deal about the composition of the Europan surface. Even if it had not been placed on a collision course for the moon, the spacecraft could have continued collecting data until it ran out of orbit-maintenance propellant and allowed to become derelict.

It is true that we do not want to contaminate these places to the point that we can no longer study them. But what makes these regions special is also what makes them interesting and desirable targets. As such, I have to wonder if the best is not the enemy of the good in this case. As much as we can learn incrementally from non-special regions, the rewards of exploring these other areas are potentially much greater. Space exploration is a public enterprise, and nothing grabs the imagination of our funding base more then uncovering more about the potential for life in the solar system and our place in it. If we continue to ignore these places because we set such a high bar for their exploration, we risk loosing this valuable support.

Perhaps we should be thinking in terms of resource management. Anyone who has had a cold can appreciate the resourcefulness of the little Von Neuman machines which are terrestrial microorganisms. But evolution cannot operate in the absence of reproduction and even in special regions, conditions are not exactly clement. The chances of terrestrial contaminants merely venturing beyond the level of dormant spores, not to mention thriving and replicating, anywhere on the Martian or Europan surface is low.

As such, perhaps we could consider setting aside areas where limited local contamination is permissible. This would preserve the special regions as a whole while allowing us to get answers to our biggest outstanding questions. As well, recall that any directly interacting part or life detection sensor will need to be incredibly clean to avoid false positives, so even this compromise does not increase the risk much. As Andrew has said, there is life on Mars within our landed spacecraft. But if it is confined to that barest of inhabitable niches, then the planet remains protected.

Either way, the point may be moot soon. With boots-on-the-ground human exploration planned for not long after the current pair of missions to Mars, contamination becomes inevitable. After all, it’s hard to sterilize a creature that is 10% by mass bacteria.

For more information, you can check out this helpful Nature News article: http://www.nature.com/news/2009/090520/full/459308a.html