Space Archives - Michael Dello-Iacovo

Asteroids and comets as space weapons

A video version of this is available here.

Introduction

Approximately 66 million years ago, a 10 km sized body struck Earth, and was likely one of the main contributors to the extinction of many species at the time. Bodies the size of 5 km or larger impact Earth on average every 20 million years (one might say we are overdue for one, but then one wouldn’t understand statistics). Asteroids 1 km or larger impact Earth every 500,000 years on average. Smaller bodies which can still do considerable local damage occur much more frequently (10 m wide bodies impact Earth on average every 10 years). It seems reasonable to say that only the first category (>~5 km) pose an existential threat, however many others pose major catastrophic threats*.

Given the likelihood of an asteroid impact (I use the word asteroid instead of asteroid and/or comet from here for sake of brevity), some argue that further improving detection and deflection technology are critical. Matheny (2007) estimates that, even if asteroid extinction events are improbable, due to the loss of future human generations if one were to occur, asteroid detection/deflection research and development could save a human life-year for $2.50 (US). Asteroid impact mitigation is not thought to be the most pressing existential threat (e.g. artificial intelligence or global pandemics), and yet it already seems to have better return on investment than the best now-centric human charities (though not non-human charities – I am largely ignoring non-humans here for simplicity and sake of argument).

The purpose of this article is to explore a depressing cautionary note in the field of asteroid impact mitigation. As we improve our ability to detect and (especially) deflect asteroids with an Earth-intersecting orbit away from Earth, we also improve our ability to deflect asteroids without an Earth-intersecting orbit in to Earth. This idea was first explored by Steven Ostro and Carl Sagan, and I will summarise their argument below.

Asteroid deflection as a DURC

A dual use research of concern (DURC) refers to research in the life sciences that, while intended for public benefit, could also be repurposed to cause public harm. One prominent example is that of disease and contagion research (can improve disease control, but can also be used to spread disease more effectively, either accidentally or maliciously). I will argue here that DURC can and should be applicable to any technology that has a potential dual use such as this.

Ostro and Sagan (1998) proposed that asteroid impacts could act as a double edged explanation for the Fermi paradox (why don’t we see any evidence of extraterrestrial civilisations?). The argument goes as follows: Those species that don’t develop asteroid deflection technology eventually go extinct due to some large impact, while those that do eventually go extinct because they accidentally or maliciously deflect a large asteroid into their planet. This has since been termed the ‘deflection dilemma‘.

The question arises: does the likelihood of a large impact increase as asteroid deflection technology is developed, rather than decrease? The most pressing existential and catastrophic threats today seem to be those that were created by technology (artificial intelligence, nuclear weapons, global health pandemics, anthropogenic global warming) rather than natural events (asteroid impacts, supervolcanoes, gamma ray bursts). Humanity has survived for millions of years (depending on how you define humanity), yet in the last 70 years have seen the advent of nuclear weapons and other technology that could meaningfully cause a catastrophic at any time. It seems possible therefore that the bigger risk will be that caused by technology, not the natural risk.

Ostro and Sagan (1994) argue that development of asteroid deflection technology is at the time of writing (and presumably today) premature, given the track record of global politics.

Who would maliciously deflect an asteroid?

Ignoring accidental deflection, which might occur when an asteroid is moved to an Earth or Lunar orbit for research or mining purposes (see this now scrapped proposal to bring a small asteroid in to Lunar orbit), there are two categories of actors that might maliciously deflect such a body; state actors and terrorist groups.

A state actor might be incentivised to authorise an asteroid strike on an enemy or potential enemy in situations where they wouldn’t necessarily authorise a nuclear strike or conventional invasion. For example, let us consider an asteroid of around 20 m in diameter. Near Earth orbit asteroids of around this size are often only detected several hours or days before passing between Earth and the Moon. If a state actor is able to identify an asteroid that will pass near Earth in secret before the global community has, they can feasibly send a mission to alter its orbit to intersect with Earth in a way such that it would not be detected until it is much too late. Assuming the state actor did its job well enough, it would be impossible for anyone to lay blame on them, let alone even guess that it might have been caused by malicious intent.

An asteroid of this size would be expected to have enough energy to cause an explosion 30 times the strength of the nuclear bomb dropped over Hiroshima in WWII.

We can temper the likelihood of this scenario by speculating that it is unlikely for some state actor to covertly discover a new asteroid and track its orbit without any other actor discovering it, considering there are transparent organisations working on tracking them. However, is it possible that a government organisation (e.g. NASA) could be ordered to not share information about a new asteroid?

What to do about this problem

Even if we don’t directly develop asteroid deflection technology, as other technologies progress (e.g. launching payloads becomes cheaper, propulsion systems become more efficient), it will become easier over time anyway. Other space weapons, such as anti-satellite weapons (direct ascent kinetic kill projectiles or directed energy weapons), space stored nuclear weapons, and kinetic bombardment (rods from god) will all become easier with general improvements in relevant technology.

The question arises – even if a small group of people were to decide that developing asteroid deflection technology causes more harm than good, what can they meaningfully do about it? The idea that developing asteroid deflection technology is good is so entrenched in popular opinion that it seems like arguing for less or no spending in the area might be a bad idea. This seems like a similar situation to where AI safety researchers find themselves. Advocating for less funding and development of AI seems relatively intractable, so they instead work on solutions to make AI safer. Another similar example is that of pandemics research – it has obvious benefits in building resilience to natural pandemics, but may also enable a malicious or accidental outbreak of an engineered pathogen.

Final thoughts

I have not considered the possibility of altering the orbit of an extinction class body (~10 km diameter or greater) in to an Earth intersecting orbit. While the damage of this would obviously be much greater, even ignoring considerations about future generations that would be lost, it would be significantly harder to alter the orbit of such a body. Also, we believe we have discovered all of the bodies of this size in a near Earth orbit (Huebner et al 2009), and so it would be much harder to do this covertly and without risking retaliation (e.g. mutually assured destruction via nuclear weapons). The possibility of altering the orbit of such bodies should still be considered, as it poses an existential/catastrophic risk while smaller bodies do not.

I have also chosen to largely not focus on other types of space weapons (see this book for an overview of space weapons generally) for similar reasons – the potential for dual-use is less clear, thus in theory making it harder to set up such technologies in space. It would also be more difficult to make the utilisation of such weapons look like an accident.

Future work

A cost benefit analysis that examines the pros and cons of developing asteroid deflection technology in a rigorous and numerical way should be a high priority. Such an analysis would consider the expected value of damage of natural asteroid impacts in comparison with the increased risk from developing technology (and possibly examine the opportunity cost of what could otherwise be done with the R&D funding). An example of such an analysis exists in the space of global health pandemics research, which would be a good starting point. I believe it is unclear at this time whether the benefits outweigh the risks, or vice versa (though at this time I lean towards the risks outweighing the benefits – an unfortunate conclusion for a PhD candidate researching asteroid exploration and deflection to come to).

Research regarding the technical feasibility of deflecting an asteroid into a specific target (e.g. a city) should be examined, however this analysis comes with drawbacks (see section on information hazards).

We should also consider policy and international cooperation solutions that can be set in place today to reduce the likelihood of accidental and malicious asteroid deflection occurring.

Information hazard disclaimer

An information hazard is “a risk that arises from the dissemination or the potential dissemination of (true) information that may cause harm or enable some agent to cause harm.” Much of the research in to the risk side of DURCs could be considered an information hazard. For example, a paper that demonstrates how easy it might be to engineer and release an advanced pathogen with the intent of raising concern could make it easier for someone to do just that. It even seems plausible that publishing such a paper could cause more harm than good. Similar research into asteroids as a DURC would have the same issue (indeed, this post itself could be an information hazard).

* An ‘existential threat’ typically refers to an event that could kill either all human life, or all life in general. A ‘catastrophic threat’ refers to an event that would cause substantial damage and suffering, but wouldn’t be expected to kill all human life, which would eventually rebuild.

My fear: spreading insect suffering to Mars

One thing I’m personally worried about is the spreading of wild-animal suffering to other planets. In the short term, I’m most worried about spreading insects to Mars. I think (and have argued here) that this might happen sooner than we think. The use of insects on Mars for either food or to help terraform seems supported (or at least warranting further thought) by a good deal of the Mars community.

Currently, a potato is in development that looks like it might be able to grow in Mars atmospheric (open) conditions. Biology is a weak point of mine so maybe I’m more worried than I should be. But I fear that if potatoes are solved, insects potentially aren’t that much harder to get to survive on Mars, especially given there are already extremophile insects.

So basically I’d like to loosely propose that shifting public opinion about the use of insects for Mars and anything else is potentially neglected, given the scale here (accidentally or purposefully putting insects on Mars which spread uncontrollably). I don’t know how confident I am about this argument, but wanted to drop it here for discussion.

The need for convergence on an ethical theory

For this post, I’m going to use the scenario outlined in the science fiction book Seveneves by Neal Stephenson. It’s a far-fetched scenario (and I leave out a lot of detail), but it sets up my point nicely, so bear with me. Full credit for the intro, of course, to Stephenson.

This is cross-posted to the Effective Altruism Forum. Please post your comments there to keep them all in one place.

Introduction

Humanity is in a near future state. Technology is slightly more advanced than it is today, and the International Space Station (ISS) is somewhat larger and more sophisticated. Long story short, the Moon blows up, and scientists determine humanity has two years before the surface of the Earth becomes uninhabitable for 5,000 years due to rubble bombardment.

Immediately, humanity works together to increase the size and sustainability of the ISS to ensure that humanity and its heritage (e.g. history, culture, animals and plants stored in a genetic format) can survive for 5,000 years to eventually repopulate the Earth. That this is a good thing to do is not once questioned. Humanity simply accepts as its duty that the diversity of life that exists today will continue at some point in the future. This is done with the acceptance that the inhabitants and descendants of the ISS will not have any easy life by any stretch of the imagination. But it is apparently their ‘duty’ to persevere.

The problem

It is taken as a given that stopping humanity from going extinct is a good thing, and I tend to agree, though not as strongly as some (I hold uncertainty about the expected value of the future assuming humanity/life in general survive). However, if we consider different ethical theories, we find that many come up with different answers to the question of what we ought to do in this case. Below I outline some of these possible differences. I say ‘might’ instead of ‘will’ because I’ve oversimplified things and if you tweak the specifics you might come up wit ha different answer. Take this as illustrative only.

Classical hedonistic utilitarian

If you think the chances of there being more wellbeing in the future are greater than there being more suffering (or put another way, you think the expected value of the future is positive), you might want to support the ISS.

Negative utilitarian

If you think all life on Earth and therefore suffering will cease to exist if the ISS plan fails, you might want to actively disrupt the project to increase the probability that happens. At the very least, you probably won’t want to support it.

Deontologist

I’m not really sure what a deontologist would think of this, but I suspect that they would at least be motivated to a different extent than a classical utilitarian.

Person affecting view

Depending on how you see the specifics of the scenario, the ‘ISS survives’ case is roughly as good as the ‘ISS fails’ case.

Each of these ethical frameworks have significantly different answers to the question of ‘what ought we do in this one specific case?’ They also have very different answers to many current and future ethical dilemmas that are much more likely. This is worrying.

And yet, to my knowledge, there does not seem to be a concerted push towards convergence on a single ethical theory (and I’m not just talking about compromise). Perhaps if you’re not a moral realist, this isn’t so important to you. But I would argue that getting society at large to converge on a single ethical theory is very important, and not just for thinking about the great questions, like what to do about existential risk and the far future. It also possibly results in a lot of zero-sum games and a lot of wasted effort. Even Effective Altruists disagree on certain aspects of ethics, or hold entirely different ethical codes. At some point, this is going to result in a major misalignment of objectives, if it hasn’t already.

I’d like to propose that simply seeking convergence on ethics is a highly neglected and important cause. To date, most of this seems to involve advocates for each ethical theory promoting their view, resulting in another zero-sum game. Perhaps we need to agree on another way to do this.

If ethics were a game of soccer, we’d all be kicking the ball in different directions. Sometimes, we happen to kick in the same direction, sometimes in opposite directions. What could be more important than agreeing on what direction to kick the ball and kicking it to the best possible world.

Xenon and lunar mining – Off-Earth Mining Forum Day 2

I woke up to the very strange sight of sunlight for perhaps the first time since I got to Sydney. With the Future Mining Conference over, all of the talks today were focussed specifically on space.

The first presentation was a review of lunar resources by researcher Ian Crawford, a summary of his paper published in Progress in Physical Geography. With only one or two exceptions, Ian claims, there are no resources on the Moon that would be worth importing back to Earth. The real market would be to use lunar materials on the lunar surface itself, or to use them in cis-lunar space.

Helium-3, touted by many as the solution to all of our energy woes (and the subject of the sci-fi novel by the name of Limit, which I highly recommend despite its 1000+ page length!), is implanted into the lunar regolith by solar wind. But, it only exists at an average concentration of 4 ppb in the regolith. As such, Ian is very sceptical about the economic feasibility of extracting and returning He-3 to Earth. If you’ll allow me to paraphrase him:

“Assuming equal efficiencies, in 1.4 years, the same solar energy falls on 1 metre squared as would be obtained from extracting and processing all the helium-3 contained in the 3 m of high titanium regolith below it.” A rather damning statement.

Some areas of rare Earth elements (REEs) such as uranium and thorium are enriched in some areas, but REEs, despite their name, are not actually that rare, and are certainly not rare or valuable enough to warrant returning to Earth – UNLESS Earth-side supply dropped (e.g. it became too environmentally unfriendly to extract).

A large economy in cis-lunar space (e.g. science, infrastructure, transport, tourism…) may tip the economics over the edge to make lunar exploration and exploitation viable. Note that it takes much less energy to get to Moon escape velocity and down to geosynchronous Earth orbit (GEO) than it does to get to GEO from Earth’s surface. If Moon infrastructure were sufficiently developed, it could become far more cost efficient to build infrastructure in GEO using Moon resources.

This was followed up by Jim Keravala, Chief Operating Officer of Shackleton Energy, who gave us some idea of the infrastructure that might be built in GEO. Shackleton proposes that solar panels, which are much more efficient at collecting energy in space than on Earth, could be built and used to transmit wireless power back to a receiver on Earth’s surface. The energy is non-ionising and thus not a danger to life. This technology is feasible and demonstrated (for example), and can achieve energy transmission efficiencies of around 54%.

Kyle Acierno of iSpace, who are chasing the Google Lunar XPRIZE, gave a quick summary of their progress. The first prize of $20 million goes to the first non-government group to land a rover on the Moon, have it drive 500 metres and broadcast high definition video feed back to Earth. iSpace has developed a small, lightweight rover weighing just 4 kg (compared to the Curiosity Mars rover weighing in at around 900 kg!) to do just this. It is able to be so light because it is purpose built specifically for the prize goals, and contains no science equipment, and it uses 4 wheels instead of the standard 6 for rovers.

Winning the prize is the first step in a long-term plan to spend a swarm of lightweight, cheap rovers to the lunar surface to explore and demonstrate technology, eventually leading to resource extraction and the selling of scientific data. For information about their team and rover click here.

A schematic of the iSpace rover. Apologies for the low res… time for a new camera?

My favourite quote of the day was actually outside a presentation, and consisted of someone loudly exclaiming “No there is NOT more xenon than oxygen in the atmosphere!”

I found out today that the talks were actually live streamed, and you can find some of them here.

I immensely enjoyed the conference – it was a great chance to learn what is happening in the space resource utilisation industry and to meet and collaborate with fellow researchers. For anyone working in this space, or even just interested, I strongly recommend going to the next one in 2017.

Until next time (hopefully before 2017).

Space dust and ethics – Future Mining Conference day 2

Today started at the much more relaxed 8:45 am – not because the conference organisers felt like that was a more appropriate time, but because our Minister for Industry, Innovation and Science decided he couldn’t make it. Or something. I felt doubly snubbed as Pyne is my local MP AND a graduate of my school. C’mon Chris.

There were a lot of great talks today, (and definitely more of a space theme) so I’ll just summarise some of my favourites.

The morning started off with a presentation by Rene Fradet, Deputy Director of NASA Jet Propulsion Laboratory (JPL), on the potential for a common journey between exploration/science and mining in space. My supervisor introduced me to Rene over lunch and we were able to broach the possibility of visiting JPL in California (or even spending some time researching there!?) and collaborating with their scientists, some of whom are also working on mapping the interior of asteroids with geophysics.

Dr Seher Ata from UNSW spoke about ‘Resource recovery in space’, or more specifically, how to process and separate materials in space. If we want to to mine and then utilise material in space without having to bring it down to Earth, we’ll need to develop ways to process and separate materials in a microgravity environment. Many terrestrial separation methods such as froth flotation and magnetic separation rely on gravity. For example, using magnets to separate out magnetic material is only worthwhile if everything else is being pulled away by gravity, and bubbles won’t rise in a liquid, which makes froth flotation difficult to impossible. One audience member suggested centripetal force, but as you add more moving parts you increase the chances of something going wrong. I wondered aloud why we couldn’t utilise that lovely vacuum we have around us in space to induce some kind of air flow/movement and use that instead of gravity. Apparently that wasn’t actually too bad an idea, and I was told to look into it. Geez, I’m just a geophysicist! Let me know if you are a metallurgist and have some clue on how to advance this crack pot idea.

Another good talk was by Dr Jeff Coulton from UNSW Business School about an MBA elective he ran on costing resource projects. To make things a little more interesting, he gave the students a choice between three off-Earth mining projects; mining Ceres, mining the Moon or mining a near Earth orbit asteroid (NEO). The students were mostly from an IT or finance background, and so had little technical experience in terms of space science or engineering. They were told to assume the project was technically feasible, and to make assumptions on costs, resource values, demand etc. This simple experiment suggested that mining the boon had an initial capital expenditure of $9 billion (Au) and a net present value (NPV) of around $-450 billion. So you would lose $450 billion. Not very attractive. But – mining Ceres had a capex of around $22 billion and an NPV of around $80 billion, and mining an NEOhad a capex of just $492 million and an NPV of $295 million. Of course, these assume technical feasibility for these projects, which isn’t necessarily true at present, but what they demonstrate is a strong reliance of economics on the choice of discount rate and selling points.

I was pleasantly surprised to see a few talks on space law, but just plain surprised to see a presentation by an academic on space ethics. He opened his presentation with “As a humanities scholar I’m going to do something that annoys non-humanities scholars, and that is to read to you.” And he did just that. But I must say it was an enjoyable talk which got me thinking about a few things I hadn’t considered. For example, Dr Thom van Dooren focussed on the point that the economic, environmental, technical, scientific and cultural concerns related to space cannot be addressed individually, they are all entangled. Despite the low chances of humanity establishing a backup planet elsewhere, the implications for our survival and expansion are profound. One way to look at this is called ‘worlding’ – “What kind of world are we creating and what are the implications for whom?”

For example, mining helium-3 on the Moon might have obvious positive implications for some, but for others, damaging space environments may be seen as intrinsically wrong, and for others still it may be seen to be offending deities. How do we balance these concerns against others? Van Dooren argues that their concerns are not null.

Professor Steven Freeland began his presentation on space law with an amusing story. He was reading an article about space law in the Wall Street Journal. Oh great, he thinks, this will be interesting. Then he sees the title: “If a Martian crashes into your spacecraft, who is liable?” After a theatrical groan, he decides he can make a better summary of space law than the article.

Dr Alice Gorman gave a unique account of the importance of cultural heritage on the Moon and the implications of Moon dust, which, surprisingly, is actually a pretty big problem. Lunar dust is extremely sharp and abrasive due to the lack of erosional processes such as wind and flowing water. The grains can be highly electro-statically charged, and can levitate, especially when the terminator (sharp night/day boundary on the Moon) passes, due to the rapid change in temperature. Some particles are even assumed to reach lunar escape velocity speeds when human activity such as rover are in the vicinity. Imagine one of these dust grains hitting you at escape velocity!

Images of microscopic lunar dust. Image from commons.wikimedia.org.

Widespread mining of the lunar surface may even create an upper atmospheric dust layer, which could prevent aforementioned particles at escape velocity from actually leaving the surface. The implications of such a feature forming were left for us to imagine!

Apologies to any presentations that I missed, as they were all excellent talks. Leave a comment below or email me if you’d like to hear more about any of the talks, and I can go into more detail and discuss. A list of conference papers can be found via this link.

Tonight featured a presentation by Brian Muirhead of JPL, who is the manager of NASA’s Asteroid Redirect Mission (ARM). I’ll do a separate blog post about that as it’s a mission I’m really excited about, but for now I’d just like to share this very amusing and poignant image.

Maybe the dinosaurs would have survived if they had put more funding into their space program? Let’s not make the same mistake.

The Future Mining Conference finished up today, but the Off-Earth Mining Forum will continue tomorrow, featuring more talks from asteroid mining start ups and space scientists/engineers.

Until then.

Landing on a comet

The AusIMM Future Mining Conference kicked off tonight with a presentation by Professor Monica Grady about the Rosetta (accompanied by the Philae lander) mission to comet 67P/Churyumov-Gerasimenko (which I’ve done a post on here). If you don’t know Monica, here she is celebrating Philae’s successful landing on 67P. Unfortunately for her, she hasn’t realised that it promptly bounced off, but more on that later.

Professor Monica Grady demonstrating gravity assists.

“Why go to a comet?” asks Professor Grady at the start of her talk. Comets contain carbon and water, the building blocks of habitable worlds. Quite possibly, a good deal of our carbon and water here on Earth came from comets. The more we understand about comets the more we understand about our own origins.

In 1986 three probes were sent to 1P/Halley – Vega 1, Vega 2 and Giotto. This was the first comet we got up close and personal with, but we didn’t attempt landing. Then in 2006 the Stardust mission visited 81P/Wild 2, but again, no landing. Stardust did, however, collect dust from the comet’s tail and return it to Earth, allowing us our first glimpse at cometary material. However, due to the capture mechanism, carbon was difficult to capture and so we couldn’t analyse it. Finally, after 10 years in space and using gravity assists from Earth and Mars, Rosetta reached 67P.

Due to the nature of space mission design, the on-board instruments need to be finalised several years in advance so they can all be properly integrated together. As a result, the instruments being used now to study 67P were designed in the late 1990’s / early 2000’s, which by today’s standards of technology is ancient!

Comet 67P/Churyumov-Gerasimenko. Image from wikipedia.org.

For the purposes of planning Philae’s landing, scientists and engineers assumed that 67P was roughly spherical and had an average comet density. In 2014, we got our first close up picture of 67P. Definitely not spherical. This meant we severely underestimated the gravitational pull of the comet. But that’s ok, the engineers said, that’s why Philae has harpoons to tether to the surface!

10 potential landing sites were selected. Care was taken to pick a spot that wasn’t too sunny (so the equipment wouldn’t fry from the intense heat of the sun), not too dark (so the solar panels could charge), not too steep and not too rocky (so Philae wouldn’t fall over). How did they go? Well, at least the equipment didn’t end up frying.

The below picture is the last image taken of Philae as it left the Rosetta craft. With much excitement and anticipation, the leadership team, 11 principal investigators and the media waited in a conference room for the fateful landing.

The last image taken of Philae as it leaves Rosetta.

They waited 7 hours. Entertainment was provided by promotional videos such as this one (featuring ‘Littlefinger’), which I’m told got a little tired after the third time.

The investigators knew Philae bounced immediately. For a split second, they started to receive results from the comet surface. As soon as celebration erupted from the conference room, the data feed stopped. Not a good sign.

This cartoon from ESA provides a (somewhat simplified) explanation of what happened.

I could go into greater detail about an incredibly detailed presentation, but I need to be up in 7 hours to register. Who starts a conference at 8 am?

Until tomorrow.

The geological mysteries of Ceres

Ceres – a 950 km wide dwarf planet in the main asteroid belt between Mars and Jupiter. As Dawn approached in early 2015 it detected strange bright spots on the surface in a 90 km wide crater later named the Occator Crater. They were so bright they dominated the pixel they resided in on the camera. Now, many months later, NASA’s Dawn team has still been unable to place their origin, though they are finding similar, but smaller, bright patches and streaks all over the surface. Initially, these were predicted to be the result of highly reflective ice, supported by a haze (possibly sublimated water) visible over the bright spots. The best guess at this point is a highly reflective salt, though a mechanism for how and why this salt is exposed at the surface is yet to be confirmed. Possible explanations include surface impacts removing surface material covering the salt (possible for the Occator Crater, but unlikely for the smaller streaks), or some internal mechanism for the salt rising to the surface, which would suggest a geologically active body. Such small bodies have historically been thought to be long since inactive, but Pluto is only 236 km wider and showed remarkable features that are almost certainly due to recent geological activity.

The Occator Crater - showing differences in elevation and the mysterious bright spots. Image from NASA/JPL-Caltech/UCLA/MPS/DLR/IDA. — The Occator Crater – showing differences in elevation and the mysterious bright spots. Image from commons.wikimedia.org.

The surface of Ceres appears to be covered with a hydrated rock alteration product, and may have some areas covered with frost. Thermal models also indicate that Ceres is an icy object subject in the past to hydrothermal activity and differentiation which would give it layers similar to Earth’s inner/outer core, mantle and crust, and even suggest the possibility of a liquid subsurface.

Dawn has generated a topographic map of Ceres’ surface in extraordinary detail. Carol Raymond, deputy mission chief from NASA’s Jet Propulsion Laboratory has noted that the shape of the craters on Ceres are irregular, resembling those on Saturn’s moon Rhea more than those on Vesta, the second largest body in the main belt. A mineral composition map reveals streaks across the surface around the Occator Crater that researchers believe may be relevant.

Topographic map of Ceres showing changes in elevation with a pixel resolution of 400 m. The Occator Crater is located centre right. Image from NASA/JPL-Caltech/UCLA/MPS/DLR/IDA. — Topographic map of Ceres showing changes in elevation with a pixel resolution of 400 m. The Occator Crater is located centre right. Image from commons.wikimedia.org.

Another great unsolved mystery is the origin of the feature known as ‘The Lonely Mountain’, a 6 km high feature with an approximately pyramidal shape. There is no evidence of volcanic activity or plate tectonics on Ceres that might have thrust up such a feature.

The Lonely Mountain. Image from NASA/JPL-Caltech/UCLA/MPS/DLR/IDA. — The Lonely Mountain. Image from commons.wikimedia.org.

I noticed that the mountain is somewhat reminiscent of the centre of some craters on the Moon, for example the crater Alphonsus, pictured below. The centre feature of Alphonsus is also pyramid shaped, but unfortunately the similarities seem to end there. It only rises 1.5 km from the Lunar surface and is surrounded by ejecta material from the impact which created the crater. As seen in topographic images, The Lonely Mountain does not appear to sit within any consistent surface depression the might suggest an impact. It’s possible that subsequent impacts and events have erased evidence of a crater, but if so they have carefully avoided the mountain in the centre. The small crater adjacent to The Lonely Mountain is of approximately the same size and appears to be too close for coincidence. I’m not saying the material from the crater was directly translated to the mountain by some kind of impact, but there may be a relationship.

The Alphonsus Lunar crater. Image from commons.wikimedia.org.

Dawn will cease operations in mid-late 2016 and remain in orbit as a permanent satellite of Ceres. Let’s hope we will collect enough data from Ceres’ surface to solve these questions and more before then.

Water on Mars

Unless you’ve been sleeping under a rock you’ve no doubt seen the announcement by NASA today that water has been discovered on Mars (sort of, but we’ll get to that in a moment). After a day of sensational hype created from NASA’s pre-warning of an important press release, this was making headlines from the word go, with everyone speculating on the topic of discussion. The discovery of aliens, mysterious artefacts and water on Mars were all proposed.

Here is one of the images which helped make the discovery. Images of the same part of Mars’ surface at different times shows these streaks appearing between shots, indicating an active landscape. The dark streaks are on the order of 5 metres wide, often narrower, were first discovered over a decade ago, and have been called ‘recurring slope lineae’. There were numerous proposed causes for these, including water, but also avalanches or grains of material rolling down slopes.

Once the CHRISM spectrometer was applied to these streaks, the spectral signature of the features could be analysed, revealing their composition. Hydrated salts were found on every streak, but were strikingly absent from the surrounding surface. Water turns to liquid on Mars’ surface at 0 degrees Celsius, just as it does on Earth, but water with a high concentration of salts will melt at much lower temperatures (try this at home with some table salt!). The flows appear when temperatures rise over -23 degrees Celcius, which is reached during the warm season in parts of Mars.

Researchers are working on determining where this water has come from. Possible theories include porous rocks under the surface and saline aquifers existing in some areas below the surface in areas. Alfred McEwen, a planetary geologist, prefers the theory that the salts exist on the surface of Mars, and absorb water from the atmosphere until they reach a point where they have enough liquid to flow downhill, a process known as deliquescence. To me this would indicate that the surface of Mars where these features form would be laden in salts, but as mentioned earlier the spectral imagery does not seem to support this theory.

So why sort of? To be precise, we haven’t directly detected water flowing on Mars, only signs (however promising) that point towards water flow. But we must always be cautious and consider other processes that may create the same results (or even processes we have never encountered before!).

“Does this mean life on Mars?” everyone cries. The presence of liquid water (however transient in this case) is a good sign for the existence of life. Dr Grunsfeld of NASA has stated that “If I were a microbe on Mars, I would probably not live near one of these [sites]”. He suggests that underneath a freshwater glacier, such as those suspected in the north and south, would yield more ideal conditions for life.

In any case, these are certainly exciting times for Mars exploration. Of course, a ground-truthing experiment (physically checking these sites, drilling and collecting samples) would prove this theory right or wrong. Here’s to hoping we can get a geologist to these sites soon! If anyone asks, pick me.

How to make a comet

Hey space lovers! I’ve recently signed up to be a member of The Planetary Society and if you should too if you aren’t already. Not only do you get an excellent t-shirt (see below) and a quarterly issue of The Planetary Report magazine, you are funding space advocacy and adding your name to an important body that will promote space exploration.

Have you ever wondered why comet 67P looks the way it does? It’s a strange shape and looks a little like 2 bodies that have been fused together, but to the researcher’s surprise, the cometary activity appears to originate in the neck. Why? Rapid temperature change in the neck, causing cracks and inducing volatile loss. Check out Emily Lakdawalla’s blog entry for the full spiel!

Comet 67P/Churyumov-Gerasimenko. Image from wikipedia.org.

Humans to Mars – For and against

Today I was reading an article by Frank Stratford, CEO and founder of MarsDrive, about the benefits of going to Mars. I was nodding my head in agreement as I usually do, but after looking at the comments, one by Heinrich Monroe particularly threw me. It’s a long one, so I’ve picked out the key points (in my opinion).

“Oh, we’re going to get spinoffs from it? Like “from medical technology to food and water to new materials, safety technologies, and so much more”? … You know, if we spend $100B on just about any massive technological and engineering goal, spinoffs like that… will fall out as well. The question is whether those spinoffs were really worth $100B, and whether we couldn’t have gotten more value on them with smarter investment.” – Heinrich Monroe

When I talk about the value of having space science programs, in addition to the intrinsic value of advancing scientific understanding, I often refer to the unforeseen advances in technology that come as a result. For example, we probably wouldn’t have instant global communications via satellite feed, let alone the host of material science, medical and software advances that have resulted from space programs. But the comments made by Heinrich did make me wonder whether we could have achieved these better with direct, targeted programs.

Image taken from www.reddit.com. Unfortunately I'm unable to credit the original poster. — Image taken from www.reddit.com. Unfortunately I’m unable to credit the original poster.

As Donald Rumsfeld has said, there are known knowns, known unknowns and and unknown unknowns. We don’t even know about some of the discoveries to be made working on space science and their implications to every day life until we make the discovery. However, one could perhaps say the same about a targeted research program. It’s certainly a tricky one to answer, although I will say this.

There is a lot of money being used for things that I disagree with ethically, and that isn’t being used for programs such as advancing medical science. By advocating for more space science funding, I’m not convinced that this would greatly cannibalise funding going towards these other programs. It’s not a choice between one or the other.

Having said that, I would be very interested to see a study that estimates the value of space science research compared to direct research in other fields. This is presumably very difficult, as it’s hard to put a number on the value of science development (would discovering life on Mars have intrinsic value?), but this shouldn’t stop people from trying. I’m sure something like this exists, but given my experience in determining the effectiveness of charities, I wouldn’t be that surprised if it didn’t. One example is the fact that for every dollar invested in NASA, there has been a $7-14 return on investment. If you are aware of any general studies of this nature, feel free to put a link in the comments below.

I may be biased – I am a space science researcher after all!

Here is a link to a neat infographic that summarises the spin-off benefits of NASA technology and funding.