Panorama of faulted Pleistocene sediments exposed in the Corinth Canal wall, Greece

Friday, 15 September 2017

Why Cassini had to Die

This morning, the 15th September, after 20 years in space, Cassini ended her mission exploring the Jovian and Saturnian systems, intentionally vapourising itself by crashing into the atmosphere of Saturn. Due to the huge distance they had to be relayed, signals of the data collected right up until the moment of destruction took several hours to reach Earth.

Artistic visualisation of Cassini starting her final plunge towards Saturn (Credit: NASA)


The death of Cassini was of utmost importance for the Planetary Protection of the outer solar system (see PPOSS.org). The more Cassini’s observations have taught us about the icy moons of Saturn and Jupiter, the more we have realised just how complex, interesting and important these extraterrestrial worlds are.

Enceladus, Europa and Ganymede are all now known to contain vast internal water oceans under a protective icy shell, Titan has a complex atmosphere full of organic molecules and lakes of hydrocarbons on its surface. There is a chance that these environments may harbour life or at least have complex systems of pre-biotic chemistry. In this respect Cassini created more questions than it answered, creating massive interest in further exploration of these bodies, with specific life detection missions.


Cassini discovered Enceladus has a subsurface ocean and water vapour plumes which contain organic matter and evidence of water-rock interactions - the building blocks and  a potential energy source for life (Credit: NASA)


Cassini saw through Titan's thick hazy atmosphere to discover  a hugely complex world with hydrocarbon lakes, methane rain and active geology (Credit: NASA)

In order for future missions to study these questions, we must not contaminate these bodies with terrestrial microbes or organic contaminants which may accidentally be detected and mistaken for indigenous alien life. This is where planetary protection comes in. Cassini was dirty, not having undergone strict contamination control cleaning procedures and so will have been carrying an unfortunate payload of microbes and organic molecules. If Cassini had been allowed to continue its orbit around Saturn unchecked, its orbit could have decayed over time leading to a crash landing on one of the moons which may have led to uncontainable and irreversible contamination.


Cassini’s fiery death therefore saves the pristine conditions on these fascinating moons for future generations of scientists to explore. 

Goodbye Cassini and thankyou

Artistic visualisation of the Cassini's final moments burning up in Saturn's atmosphere (Credit: NASA)

Wednesday, 23 August 2017

3 Days, 3 Rock Types and 100 Million Years: Climbing in Devon

This (extended) weekend just gone, Dan, one of our regular ex-Norwich climbing partners, took us on a climbing tour of his home crags in Devon. This was an excuse for me to look at some nice rocks and we managed to get on three different rock types, covering over 100 million years of the geological history of the UK, over the three days.

Simplified geological map of Devon showing the three locations (adapted from Kirkwood et al., 2016)


Day 1: Baggy Point - Sandstone

Saturday, starting off at Baggy Point near Croyde. The climbing here is on the 360-370 million year old, Upper Devonian Baggy Sandstone Formation. They overlie the Upcott Slates and are themselves overlain by the Pilton Mudstones, all together a making up a 450m thick succession of interbedded sands, silts, muds and thin limestones charting a changing river delta succession which at first built outwards as sea level fell and then retreated inland as sea level rose again.

Due to their age and the pressures and temperatures they have been subjected to these sandstones are slightly metamorphosed and so are much harder than more recent sandstone deposits (such as those known to climbers as the Southern Sandstones around Kent) and so are a lot more solid to climb on. Routes (such as the classics Lost Horizon and Shangri-Lai) follow angular fractured cracks up otherwise sheer faces while harder routes tackle the blank slabs themselves, relying on delicate footwork and careful movement with little means of protection.

Rob leading Lost Horizon following a steep crack system

The sheer faces plunging steeply into the sea that characterise the climbing here were originally horizontal as the sedimentary sequence was deposited on the sea bed. However, during the Late Devonian and Carboniferous Periods these rocks felt the distal effects of the mountain building event known as the Variscan Orogeny. The continents of Gondwana and Laurussia collided to form the supercontinent Pangea highly folding and faulting the rocks as they were compressed together. At Baggy Point this tilted the sequence very steeply to bring the ancient sea bed to a near vertical orientation and creating the sheer, almost featureless, delicate slabs which are a feature of the climbing here.

Dan leading while I belay on the second pitch of a route up one of the steeply dipping slabs at Baggy Point (credit: C. Wade)

Unfortunately due to the interbedded weaker muds and the highly erosive sea cliff environment a lot of the rock here is quite fragile and we pulled a few dangerous chunks off into the sea as we climbed.

Day 2: Daddyhole - Limestone

Sunday, now we’re climbing a little further back in time to the mid-Devonian at the cliffs of Daddyhole in Torquay. This is very close to the Devonian type section at Torbay (which I have written about before as part of the UEA Slapton fieldtrip). The plan was to climb on the lower part of the sequence at Daddyhole Main Cliff, however, due to the long commiting nature of the routes down there and the incoming rain we were forced to visit the uppermost part of the sequence instead at Daddyhole Upper.

The mid-Devonian Limestones here were deposited around 400 million years ago when the UK was located within the tropics and Devon was beneath a warm, shallow, tropical sea. The limestones here represent a sequence from a thriving offshore reef system, well away from any polluting terrestrial input, with corals, sponges, shellfish and other organisms being highly abundant in the fossil record. Overtime (up the sequence/cliff face) the limestone becomes ‘dirtier’ as more sand and mud reaches the area from the nearby landmass and the reef life is gradually choked out, a process helped by nearby volcanoes occasionally burying the reef in ash deposits.

Spot the Dan, he's pretty much at the boundary between the cleaner massively bedded limestones and the siltier, finer bedded sequence above

The impurity of the limestone and interbedded siltier layers mean that the climbing at Daddyhole Upper is somewhat ‘esoteric’ with plenty of loose, crumbly rock and so it is not the most popular venue. This does however mean it has not taken on the smooth mirror-polished quality of more popular limestone crags (such as much of the climbing in Portland or Cheddar) and the combination of weathered out juggy limestone cracks and grippy rock is a rare delight (as long as you don’t think about how sketchy all the gear placements are. Unfortunately rain quickly stopped play here and we only got a single route in before retreating for a seaside Devonshire cream tea.

Charlotte's favourite type of climbing


Day 3: Dartmoor - Granite

Monday and its back to the future on the granite of Dartmoor. This is part of the massive Cornubian Batholith (batholith = large body of magma) that welled up underneath the southwest of England around 300-275 million years ago, during the Late Carboniferous-Early Permian. This outcrops at various localities all the way from the Isles of Scilly to Dartmoor, but is known (from a low density gravity anomaly) to extend more than 100 km further southwest under the sea.

The formation of this huge body of molten rock is related to the same mountain building event as the folding of the Devonian sediments (that we climbed on the previous two days) it intruded into. Partial melting of the lower crust occurred at a late stage during the mountain building process (after the majority of the folding had already occurred) and extension of the crust allowed the batholith to rise irregularly as ‘blobs’ to higher levels.

Over time, the softer sedimentary rocks that were intruded into have preferentially eroded away, leaving behind these granite ‘blobs’ exposed as Tors on areas such as Dartmoor. As the overlying rocks were removed the granite was unloaded and expanded, fracturing both horizontally and vertically and peeling itself apart. This produced the horizontal breaks, vertical cracks and juggy flake systems that characterise climbing on the Tors of Dartmoor.

Dan wedging himself in a nice big crack, note the horizontal joints too (credit C. Wade)

Large, sharp phenocrysts (big crystals) of plagioclase stand out proud from the otherwise surprisingly smooth and slippery blank sections of granite face. These tell the geologist that the granite cooled in stages, the big crystals grew slowly at depth before the magma rose upwards to shallower, cooler levels and finished solidifying quicker so the rest of the crystals (the groundmass) are much smaller. For the climber, delicate, precise footwork or desperate crimping and hauling with the fingertips on these small protrusions is often the only way to make progress on the harder routes. The sharpness of these crystals tears into the skin restricting the number of attempts you can have at a hard move before bloody fingers stop play, but gives excellent friction allowing your climbing shoes to stick to the smallest nubbin.

Me climbing Vandal & Ann, run out and sketched out trying to figure out the best way of using a series of crappy little crystals to get to the safety of the next big break (credit C. Wade)

Clearly in three days it is only possible to scratch the surface of the number of different rock types and climbing venues available in the southwest and we will return soon to sample more of their esoteric delights. Although it’s back onto my favourite Peak Grit for the upcoming bank holiday weekend.

Sunday, 6 August 2017

Mars Sample Return

This week I’ve been at a NASA and National Science Academies hosted planetary protection workshop in Washington DC, representing the European Science Foundation and the Planetary Protection of the Outer Solar system  (PPOSS) team (everyone important was busy/on holiday). The workshop was focused on planetary protection for the Mars 2020 mission which has an extra element of complication as it is a sample return mission – well, the 2020 mission is actually a sample caching mission, they haven’t quite figured out when and how the collected samples will be returned by a future mission….

Mars 2020 Rover (nature.com)


Sample return is a double problem for planetary protection as we have to worry about both forward and backward contamination. Forward contamination is an issue for all life detection missions, this is when the spacecraft is contaminated by hitchhiking microorganisms and organic molecules which could confound the results of the scientific experiments. This may lead us to believe we’ve found life on Mars (or wherever we’re visiting) in what is known as a false positive, or, signals from contaminants could swamp the instruments so that we miss small crucial signals of extraterrestrial life, or prebiotic organic molecules (the building blocks of life) – a false negative. Backward contamination is the worry that a sample return mission may bring back dangerous microorganisms or other infective agents such as viruses or prions (what is a prion?). This is only a concern for sample return missions that bring back material from localities which are potentially habitable, including certain areas of Mars which may have just enough water to host microbial life under the surface where it would be protected from the deadly radiation on the surface (which is why both Mars 2020 and ExoMars will have drills for subsurface sampling).

The likelihood of a sample return mission bringing back something dangerous is incredibly low, we currently have no evidence of life on Mars (whatever the conspiracy nutjobs claim). It is unlikely that Martian life would be compatible with, and therefore able to infect pathogenically, Earth life as it would have either evolved completely independently or had billions of years since a last common ancestor. However, despite the low chances, NASA (amongst others) is still taking this risk very seriously as the consequences of a Martian pathogen could be catastrophic (think Andromeda Strain) as no life on Earth would have antibiotic resistance to it.



Because of this, a large proportion of this meeting was given over to US governmental policy makers to discuss how the spread of invasive species are stopped, how disease outbreaks are dealt with and current biosafety and biosecurity policies and procedures. The overall take home message from this is that even though there is a lack of data and low chance of anything dangerous happening, the public will be very concerned about back contamination and it is public opinion which will force policy change rather than the science. Because of this we need to get the public interested and on side, through risk communication and societal participation – such as citizen science type projects (as SETI have done in their search for extraterrestrial signals) – to combat scaremongering groups early on (there is already a committee against Mars Sample Return although they appear to be currently inactive). It was also made clear that we need an international input as consequences, however unlikely, would be global.

Lessons for preventing backward contamination from Mars Sample Return can be taken from looking back at how it was dealt with for Apollo 11, the first mission to bring lunar samples back. As we knew so little about the moon at that point the astronauts were immediately quarantined on return and the samples were tested for infectious or toxic agents by exposing a wide variety of plants and animals to them before they could be released to labs around the world and the astronauts could be let out (obviously there was nothing living in the samples as we now know that the moon is a very inhospitable place).

Crew of Apollo 11 in quarantine (NASA)


Other than this it was interesting to hear a recurring point, by the presenting scientists, on the Podium principle which was just how much evidence you need to have gathered to be able to stand up and say ‘Yes, we’ve found life’. The answer, it seems, is a lot, much more than anyone has found so far. This principle has not always been followed quite extensively enough. In the ‘70s, proof for life on Mars was claimed (and still is to this day by the lead author) after life detection experiments carried out by the Viking lander seemed to show an active metabolism in the Martian soil with nutrients being consumed and carbon dioxide given off when warmth, water and food were provided. However, the results of this experiment can be explained more simply by the presence of reactive oxidising minerals in the soil (such as the perchlorates I work on) which we know are definitely there from other analyses carried out. In the ‘90s structures in the Alan Hills meteorite were claimed to be fossilised Martian bacteria, although these were later shown to be abiotic (non-life) mineral structures the study of this meteorite really kicked off the field of astrobiology as interest in finding alien life was dragged into mainstream science.

Structures in the Allan Hills meteorite suggested to be fossil bacteria (NASA)


Outside of the meeting I had to go visit the Smithsonian Air and Space Museum to go and look at relics of the Apollo space missions which collected all of the lunar samples that I have been working on. Putting the work I do into context with the amount of effort that went into getting these samples was quite humbling although it was odd to see people queuing up to touch a tiny polished piece of moon rock when I’ve destroyed a fair amount of this priceless material. And of course I couldn’t miss a chance to get a selfie with a life size model of Curiosity!




Unfortunately the trip hasn’t gone completely smoothly as I’m writing this whilst stuck in Detroit airport where I spent last night sleeping (well attempting to) under a bench after I missed my connecting flight home to London thanks to storms delaying my flight leaving DC. So I’ll be spending 17 hours in Detroit airport before flying over to Boston to connect to Heathrow and getting home a day later than planned – fun times. 

Monday, 19 December 2016

Planetary Protection of the Outer Solar System workshop

PPOSS logo (www.pposs.org)
I started writing this post on the flight home from a few days in Cologne at a Planetary Protection of the Outer Solar System (PPOSS) workshop. The PPOSS project is a EU led international collaboration of academics and industry working toward a code of best practice for planetary protection for future space missions to the bodies of the outer solar system – such as the icy moons of Jupiter and Saturn and asteroids.

Planetary Protection (PP) encompasses our attempts to minimise the chances of contaminating another world with microbes (biological contamination) or organic matter (organic contamination). This is important as if microbes survived the journey through space (which experiments have shown to be possible) and the destination proved habitable for them, then they could colonise. This is bad for two reasons; the current or future development of any indigenous life could be affected and the scientific integrity of the results of future missions would be compromised. Even if just dead microbes or non-biological organic matter are transported to the study locality then the results of experiments would still be contaminated leading to false positives and masking the detection of indigenous molecules or life.

To avoid this forward contamination a lot of effort has to go into building landers in sterile environments, making sure they are clean to strict requirements and ensuring that the orbits of orbiters and flyby missions are such that they will not impact areas of interest. The level of PP necessary increases with the potential habitability of the body of interest, for example our moon and small, dry asteroids have much lower requirements than Europa and Enceladus - which are both now believed to contain significant amounts of liquid water (a prerequisite of all known life). Backwards contamination is also a theoretical problem to avoid. This is where extraterrestrial microbes are brought back to Earth by a sample return mission - raising the possibility of infecting our planet with alien life. And procedures must be put into place to quarantine samples because of this.

Enceladus is a high risk for forward contamination due to the presence of large amounts of liquid water (image: http://solarsystem.nasa.gov/planets/enceladus)

Imperial’s contribution (and my involvement) to this project is the writing of a chapter on‘Best practice of Organic Contamination Control’ as part of a handbook aimed at those working in space science and industry. This chapter will summarise the challenges involved in keeping the icy moons free from terrestrial organic (including biological) contamination and what lessons we can take (and adapt) from the planetary protection of Mars over the last 40-odd years. This is what my supervisor and myself have been working on for the last few months and was presented at the workshop.

This 2 day workshop at The German Aerospace Center (DLR) in Cologne was to get everyone involved in the project together to thrash out a proper structure to the handbook and discuss what had already been done. Participants included representatives from the European Science Foundation (ESF - who are leading the project); the Commitee of Space Research (COSPAR); the German (DLR), Italian (INAF), Chinese (CAST), Japanese (JAXA), American (SSB) national aerospace organisations and private aerospace industries.  All with varied experience and opinions on planetary protection of various past and current missions (some of whom have been involved with PP since the first missions to Mars in the '60s and '70s).

It was a productive couple of days with many issues being cleared up by the panel, mostly to do with things being done ever so slightly differently or having different names in Europe and the US. It does look, however, that our chapter is going to need a major rewrite to get everything in that all the partners want. We may have to visit some of the European space missions that are currently being built, (such as MOMA, due to fly on ExoMars 2020) to sort out some case studies for inclusion (it’s a tough job but someone’s got to do it).

I tacked an extra day in Cologne onto the end of the workshop as I’d never visited Germany before and it coincided with the Christmas markets being in full swing. The Christmas markets are very impressive and even I couldn't help to feel festive as they pervade the whole city with Christmas music, gl├╝whein and the smell of grilling bratw├╝rst. I was shown around by Honza who also did his PhD at the University of East Anglia and is now doing a post doc in Cologne. A trip to a Bier Museum and the sampling of many of the local (very good) specialty beers resulted in a cracking hangover for the flight home.



Unfortunately now I'm back in the lab and somehow the pyrolysis unit has developed a leak while I've been away................Merry Christmas!

Thursday, 29 September 2016

Mars by numbers

At the moment my current task at work is to wade through masses of data collected and sent back down by the Mars Science Laboratory (MSL) on the Curiosity Rover and try to figure out some of what’s going on up there and how it relates to our project (which I can’t talk about yet as we’re trying to get it published). 

One of Curiosity's selfies taken at Mount Sharp (from NASA


All of the data collected by the various instruments on Mar’s chemistry, climate, geology, etc are freely accessible to anyone. So far there are nearly 1130 sol’s (Martian day’s) worth of data, with hundreds of different experiments carried out over that period. That’s a lot to get through! Although so far I’ve only really been looking at a particular kind of geochemical analysis technique (again, can’t say which) but there is so much more, some of which nobodies probably had the time to properly look at yet. All of the big released photos of the Martian landscape are actually stitched together from many smaller shots taken by Curiosity and they are also all available to download in high resolution.

What I have been able to do is plot daily climate conditions from the Rover's weather station' to look at the changes in temperature and humidity over the Martian sol. This is a plot of the weather on the 183 sol since curiosity landed on Mars.



The nighttime temperatures going down to -70 C are not far off the coldest temperatures ever recorded at Earth's South Pole (around -80 C), however, this is a pretty typical Spring day near the Equator of Mars (Curiosity's landing site, Gale Crater, is 4.6 degrees south). And with daytime temperatures close to 0 C this is a huge range throughout the day.The measured relative humidities (RH) are much lower than the driest place on Earth, the Atacama desert, where the most arid parts have an average RH of around 17 %. However, Curiosity has recorded nighttime Winter RH values of up to 70 %, high enough for frost to form, showing the wide range of potential conditions at the landing site.

With all this available data online you've got to wonder how all the people who are convinced that NASA is hiding evidence of aliens on Mars still believe that. Surely it'd be a lot easier to just not bother 'faking' sending a Rover up and then have to then make up this huge amount of data? 

I think it’s pretty cool that anybody can download and play about with data that’s cost billions to produce and has been created over 30 million miles away on another planet. Delving into this resource is the closest most (if not all) of us will get to exploring another world.

Links:



Friday, 2 September 2016

Climbing and Cleavage - the geological history of the Llanberis Slate Quarries

So after just two trips to the Llanberis slate quarries of North Wales I am now a fully converted Slate Head. The sharp crimps, invisible micro-edges and frictionless slopers create a completely different climbing experience to any other rock type; with precision, balance and feet-up-by-your-face flexibility being much more important than pure strength and power. Routes are varied, balancing their way up apparently slick vertical slabs, bridging up awkward technical grooves, jamming thin micro-wire protected seams and even powering through overhanging series of roofs - keeping things interesting.

The Dinorwic Quarry, Australia area

But what is it that makes this rock behave the way it does, creating the contrast between those sharp edges and featureless, smooth faces? The slate is old and has experienced numerous events of geological upheaval to get to how it is today.

Originally fine particles fell out of suspension to form a fine mud at the bottom of an ocean basin, the Welsh Basin, slowly building up, resulting in thick deposits over millions of years. This was back in the Cambrian Period (named after Wales, Cymru) around 540 - 490 million years ago (the slates further south around Blenau Festiniog were deposited a few hundred million years later in the Ordovician). At this time the microcontinent of Avalonia (what was to become Wales and England) was on the southern edge of a large ocean, the Iapetus.
The Welsh Basin was a back arc depositional basin, an area of extension and subsidence behind a volcanic arc, created due to the subduction of the Iapetus Ocean beneath Avalonia.


Deposition in the Welsh Basin in a back-arc setting


With the closure of the Iapetus, the Northern and Southern halves of the British Isles were pushed together in the Caledonian Orogeny through the Ordovician to Devonian times (ending around 390 million years ago). This impact formed the mountain belts of northern Wales, Scotland and the north of England (which would then have been much larger than today), compressing, folding and faulting the rocks of the Welsh Basin, subjecting them to high directional pressures. This directional pressure (or stress) caused the low grade metamorphism of the mudrocks, leading to realignment and recrystallization of platy (flat) clay minerals (micas) and forming the slates. It is this alignment of minerals which causes slates to cleave along planes of weakness in one direction. This cleavage is what made the slates perfect for use as roofing tiles and creates the sharp edges and smooth faces we see today on the rock.


Slate formation: (1) Deposition of fine platy-clay minerals in a low energy marine setting; (2) Compression during mountain building event realigns the platy minerals perpendicular to the direction of applied pressure; (3) Planes of weakness are created which the slate cleaves along 
Fast forward nearly 400 million years and the Llanberis slate quarries were mined for hundreds of years, getting deeper and deeper into the earth and creating the stepped layers of exposed rock walls we can now explore. 


Monday, 25 July 2016

Graduation: The end of an era

On Thursday I finally graduated from my PhD. That was it, over, bringing a definitive end to my time at UEA after almost 5 years. This was just a formality, the ‘certificate’ I was handed on stage was just a blank piece of paper and the ‘scroll’ in my photos is nothing more than a bit of plastic drainpipe; I’d had the real certificate sent to me months before. However, it felt important to go and bring this final stage of my education to a marked conclusion, going along with all the (somewhat ridiculous) pomp and circumstance a 53 year old university can muster.

Returning to Norfolk after a few months in London felt like coming home; the walk through the quiet, green surroundings of the campus much more pleasant than my current daily death-cycle commute through west London.

The hot summer’s day meant the full PhD robes and suit were unwelcome, but thankfully the old sports hall was air conditioned and the ceremony was relatively short. After a few speeches, a quick walk across the stage and a handshake, it was all over. That was it, my link to UEA had been severed, and it was time to look ahead to the next stage of my career (see my last post).

The blur is me, honest

Photographs were taken with my colleagues of the last few years, the ‘Lobster Room’ office had almost all managed to go through the whole process and graduate together - the remainder of us refused to be separated for the group photos. There were, however, a few surprises as to who had and had not succeeded; the PhD process is not without its casualties and last minute triumphs.
After that, it was a race to lose the robes and get down t’pub for an evening in one of the best beer gardens in Norwich to discuss the highs and lows of our time at UEA and find out how everybody is doing now – mostly very well thankfully.

Despite media reports, UEA has not banned the throwing of hats


Charlotte and I stayed in Norwich for a long weekend doing everything we missed: drinking with old mountaineering club buddies, hanging out at the climbing wall where we used to work, getting sunburnt on the beach at Wells-next-the-Sea and exploring Thetford forest.

Norfolk might be quiet, out of the way and slow paced, but it is very pleasant. We’re going to miss it.

Just chilling with some ducks in the woods - sort of sums up Norfolk really