Pluto frenzy is upon us this month

The world’s in Pluto frenzy this month. NASA’s SOFIA observatory aircraft has been operating out of Christchurch, New Zealand, to capture data on Pluto’s atmosphere via star transit spectrometry – and on 14 July, some 3662 days after leaving Earth, the New Horizons probe will storm past Pluto and its family of moons.

Simulated view of Pluto and Charon - speculative only at this stage - which I made with my Celestia software.

Simulated view of Pluto and Charon – speculative only at this stage – which I made with Celestia.

It’s our first visit to that world – and last, for the foreseeable future. And what an achievement! That probe is the fastest object ever built by humanity, and it’s already returned new data about the Pluto system. In the weeks after the encounter, as it transmits its hoard of information back – New Horizons will revolutionise everything we know about that remote world and its moons. Always assuming it doesn’t bang into anything, of course. At 51,500 km/h, an encounter with a grain of sand would do serious mischief. The fact that Pluto has one giant moon – Charon – and four smaller ones suggests the system might have been formed by an ancient collision, and there could be debris along the encounter path.

Pluto and Charon on 25 and 27 June 2015. Public domain, NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute. Click to enlarge.

The real thing: Pluto and Charon on 25 and 27 June 2015. Public domain, NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute. Yup, Pluto’s a red planet. Click to enlarge.

On the other hand, JPL officials are fairly sure the risk is minimal. The NASA team under Alan Stern used New Horizons’ long-range imager (LORRI) to look ahead for debris on 22, 23 and 26 June, concluding that the intended path ahead was safe. The Pluto system is in a state of gravitational resonance, which means any debris is expected to be clustered in discrete positions. Mostly.

New Horions' track through the Pluto system. Public domain, NASA/JPL.

New Horizons’ track through the Pluto system. Public domain, NASA/JPL.

You’ll notice I haven’t mentioned the word ‘dwarf planet’. That’s because I think it’s a stupid definition. It was voted in by the International Astronomical Union in 2006, on the last day of a conference when just over 400 delegates out of 10,000 in the Union remained to vote. Some 237 voted for a resolution defining ‘planet’ in terms that meant Pluto and a lot of other new Kuiper belt objects, and Ceres, were ‘dwarf planets’. The nays totalled 157, so the fact is that Pluto was demoted on a majority of 80, in a motion where 95 percent of members did not vote at all. To me, that’s not particularly valid – and I’m far from the only one to think that. However, despite a meme circulating Facebook to the contrary, it hasn’t been rescinded.

Part of the public howl of protest was driven by the fact that Pluto – from its discovery by Clyde Tombaugh in 1930, right up until 2006 – was always the ninth planet. Walt Disney renamed Goofy’s dog Rover after it. Pluto became iconic – to the people of the mid-twentieth century, the last, lonely world out on the edge of our solar system (probably). It was a social definition. And then suddenly 237 scientists out of 10,000 killed a popular idea that been integral with society for 76 years.

But in any case, the definition of ‘planet’ on which the IAU voted is a rubbish one. Among other things, it requires the planet to have ‘cleared’ its vicinity of debris. Even Jupiter doesn’t match that, thanks to its Trojan asteroids. And to me, it has a philosophical problem: it’s trapped by the requirement in western thought to compartmentalise – to divide a complex and often smoothly gradiated universe into sharply defined categories.

Frequently it’s an ill-fit, and the IAU definition of ‘planet’ is no exception. The problem is that the reality of our solar system, particularly as it unfolded for us from 1992 (specifically), clearly defies such classification. Trying to jam its different contents into pre-defined ‘scientific’ categories misleads, because the bits of rock, dust, ice and gases that orbit the Sun in various ways are more complex than this.

More next week.

Copyright © Matthew Wright 2015

What would YOU say to aliens before the apocalypse hits us?

Efforts are under way to crowd-source a message for putative future aliens, to be uploaded to the New Horizons probe after it completes its historic mission to Pluto and (possibly) another object in the Kuiper belt.

New Horizons is the fifth object we’ve sent on a one-way journey out of the solar system, and the only one not to have a message aboard.

Artists' concept of New Horizons' encounter with Pluto, mid-2015. NASA, public domain, via Wikipedia.

Artists’ concept of New Horizons’ encounter with Pluto, mid-2015. NASA, public domain, via Wikipedia.

Its predecessors, Pioneers 10 and 11, had a plaque; and Voyagers 1 and 2 were equipped with analogue record – with stylus.

The chance of any of this actually being found by aliens is, of course, vanishingly small. None of the probes are headed to any specific star – their departure from the Sun’s neighbourhood is a by-product of the fact that they were accelerated beyond solar escape speed as a way of keeping transit times down to their targets in the outer solar system.

Still, it’s an intriguing thought to suppose that, millions of years hence, Thog the Blob from Ursa Major might happen across one of these probes and – if the messages haven’t been eroded over thousands of millennia by interstellar radiation and dust, or the soft-copy on New Horizons lost to quantum tunnelling, maybe they’ll get a bit of an insight into a long-lost species on a far distant world.

Long lost? Sure. And that brings me to the message that might be uploaded to New Horizons. You know:

Message to aliens, affixed to Pioneer 10. It included images of humans, a route map of the probe's journey out of the Solar System, and information on the spin state of hydrogen.  Public domain, NASA, from http://grin.hq.nasa.gov/ABSTRACTS/GPN-2000-001621.html

Message to aliens, affixed to Pioneer 10. It included images of humans, a route map of the probe’s journey out of the Solar System, and information on the spin state of hydrogen. Public domain, NASA, from http://grin.hq.nasa.gov/ABSTRACTS/GPN-2000-001621.html

Dear Alien. Greetings from Planet Earth. We call ourselves human, but you probably knew that already because, by the time you’ve seen this, we’ll have conquered the visible universe and made it a better place for all. Whatever problem we face – global warming, warfare, whatever – we’ll get together and work co-operatively to fix it, in a spirit of happiness and generosity, and get on with making the universe a better place for everybody who shares it. Love from Humanity.

Or, more realistically:

Dear Alien. Greetings from Planet Earth. By the time you read this, we’ll be so long gone even our cities will be mere smears of residue in the dirt. We have this delusion that we’re special, but we never stop being stupid, stupid apes. We fight each other all the time over territories – intellectual, ideological or physical – for reasons that often don’t make sense outside a narrow imperative of personal validation or other equally selfish motive. We get hung up on status, defined often by wasteful practises that produce nothing or lead to us fighting each other. We exploit and pollute every environment we go near, until it’s destroyed – and often then go and fight each other.

“We’re good at it. Our history is littered with broken environments, lost kingdoms, wars, disputes, and a litany of inhumanity to ourselves. No matter how much we call on ourselves to care, to be thoughtful, to be tolerant, we always seem to lose track of the point. And our problem now is that we’ve run out of planet to exploit, pollute and fight over, and none of us can agree on ways to fix the problem. We haven’t got long. We hope your species, whatever it is, has a better way. Love from Humanity.

Which one do you think is more likely? And what’s your thought on the way we should advertise ourselves to aliens?

Copyright © Matthew Wright 2015

Time’s no illusion – unlike gravity. Weird but true!

It seems axiomatic these days, especially among the quantum woo set, to call ‘time’ an illusion – a perception. Of course this is scientific rubbish. There’s no question that humans perceive time in many ways, but in terms of physics time IS real, independent of how we sense its passage.

Solar flare of 16 April 2012, captured by NASA's Solar Dynamics Observatory. Image is red because it wa captured at 304 Angstroms. (NASA/SDO, public domain).

Solar flare of 16 April 2012, captured by NASA’s Solar Dynamics Observatory. Image is red because it wa captured at 304 Angstroms. (NASA/SDO, public domain).

Unlike gravity. That’s the irony, you see. Gravity’s an illusion? Why? Short answer is that the universe is actually weirder than the woo brigade know. Let me explain. According to our friend Albert Einstein, gravity doesn’t exist as a force. Of course, you might have a bit of difficulty imagining gravity is an illusion if you’ve just gone for a gutser down the front steps. But trust me – it is.

Here’s how it works.

Einstein’s Theory of General Relativity – coming up for its centenary and proven to be true, without exception, every time it’s tested – shows that space and time are one entity. A four-dimensional reality with up-down, left-right, forward-back and time.

This space-time fabric is distorted by mass/energy (the same thing in terms of how the universe works). The usual metaphor is to imagine a rubber sheet. Mass/energy can be envisaged as a bowling ball dropped into the sheet. It’ll sag, stretching and curving the rubber.

This rubber sheet, remember, reflects not just space but also time. Consequently, a large mass (or a lot of energy) alters the rate at which time passes. You experience that every day on your phone – its GPS relies on GPS satellites, which have to account for the difference in the rate of time between Earth’s surface and the altitude the satellite’s orbiting at. Time dilation is also caused by the velocity difference between the satellite and Earth’s surface – a function of Einstein’s earlier theory, Special Relativity – which adds to the mix.

GPS works by micro-precise time measurement. If the satellites didn’t take account of Einsteinian frame-dragging, they couldn’t pin the position of your phone to a few metres.

So. Time’s real. What about gravity? Well, that’s the kicker. All-round smart guy Sir Isaac Newton, co-inventor of calculus among other things, identified a relationship between mass and gravity. The larger the mass, the more gravity it has. Simple.

Albert Einstein lecturing in 1921 - after he'd published both the Special and General Theories of Relativity. Public domain, via Wikimedia Commons.

Albert Einstein lecturing in 1921 – after he’d published both the Special and General Theories of Relativity. Public domain, via Wikimedia Commons.

Newton’s theory worked perfectly well, even allowing mathematicians of the early nineteenth century to predict the presence of a new planet – Neptune – from the way it affected Uranus’ orbit. But there were points where it didn’t work. Mercury had orbital characteristics that couldn’t be fully explained by the tugs of all the known planets.

For a while, astronomers theorised there was another world inside Mercury’s orbit – Vulcan. But it could never be found. And then Einstein’s theory came along, and the whole need for Vulcan went away.

Gravity, Einstein explained, wasn’t a force at all. It was a function of mass, sure – but not quite the way Newton thought.

Instead, Einstein calculated, gravity was an effect of the curvature of space-time. Particles would always try to take the shortest route between two places. However, if space-time was curved, they’d be forced to take a curved path. The difference was what we perceived as gravity, an effect intimately associated with mass or – and this is the kicker – energy.

Energy? Sure. Special Relativity showed that mass and energy were different aspects of the same thing (a little mass = a LOT of energy – and go on, you KNOW the equation).

Enough energy, in short, would also distort space-time and, in effect, create its own ‘gravity’. And this was where Mercury came in. The pertubations in its orbit, according to Einstein, weren’t caused by a hidden planet. They were caused by the energy of the Sun itself, acting as an additional distortion in space-time. In 1919 that prediction was borne out when some very precise measurements were taken of Mercury’s position during a transit of the Sun. It was exactly where General Relativity said it should be, if gravity was actually a product of the curvature of space-time.

This was the first proof of the theory – and, as we’ve seen, it’s been shown to be true every which way, ever since.

Gravity, in short, wasn’t a force of itself; it was a function of the way space-time was distorted by mass/energy. This also explained why you couldn’t have anti-gravity, because gravity wasn’t a real force with polarity. It was a structural product of the way the universe worked, but not something real of itself.

The biggest question that came out of this, of course, wasn’t whether gravity was real, which it obviously wasn’t – but why time seemed to move only in one direction. And that’s something that hasn’t been answered. Yet.

More soon.

Copyright © Matthew Wright 2015

A chat with Elvis about Nibiru and other woo

Every other Tuesday, Elvis* – who’s living on Mars disguised as a walrus – drops in for a burger from the slider joint just down the road, because nobody on Mars knows how to make a good one. This week, as we chowed down on Chicken Anchovy Supreme, I mentioned that somebody’d posted a comment on my blog about Scholz’s Star – the red dwarf that skidded past the solar system around 70,000 years ago.

Conceptual picture I made of a red dwarf with large companion using my trusty Celestia installation.

Conceptual picture I made of a red dwarf with large companion using my trusty Celestia installation.

By this guy’s proposal the star – sorry, ‘Nibiru’ – hosted a planet with intelligent life who’d come to Earth and coded secrets into our genes, and he pointed me to a website that – er – proved it.

Actually, when I looked at the site, it was filled with stuff about aliens – aka Sumerian gods – wanting to steal Earth’s gold in order to warm their planet. A prelude, I suppose, to the way aliens always wanted to steal women and water in the 1950s.

Elvis wasn’t worried. Between mouthfuls, he told me this sort of argument is common enough among the woo brigade. There’s no point trying to counter-argue using science because the people who peddle this stuff believe what they say as an act of their own faith in it and merely get angry if you question it.

I still thought science might offer something and pointed out that red dwarfs are the smallest and most innocuous looking stars ever, but they have an unfortunate habit of suddenly exploding into a wild fury. Their brightness can increase 400 times or more on the back of a major flare. They make our local solar flares, even the biggest, look feeble. And if you’re in the way of that licking – well, there you are, an innocent little cell just starting out on the evolutionary tree, and suddenly you get the world’s worst dose of radiation poisoning and die. Oops.  And before life can re-develop, the broken bits get radiated. And again…and again…and again…

Solar flare of 16 April 2012, captured by NASA's Solar Dynamics Observatory. Image is red because it wa captured at 304 Angstroms. (NASA/SDO, public domain).

Solar flare of 16 April 2012, captured by NASA’s Solar Dynamics Observatory. Image is red because it was captured at 304 Angstroms. (NASA/SDO, public domain).

That happened on early Earth, too, when our Sun was young and boisterous. Life didn’t start developing until after the Sun had stopped lashing us. Turns out that life needs a stable environment. Red dwarfs don’t offer one – ever. And that, I explained to Elvis, was quite apart from the fact that alien life is – well, alien. The chances of an alien planet producing a biota identical to ours is pretty low.

Not to mention that Scholz’s Star is orbited by a brown dwarf companion at the distance of Venus – a companion that has three-quarters the mass of the star, meaning they’re actually orbiting a mutual point in space where their gravitation balances, the barycentre. Planets could stably orbit the barycentre, providing they were further out again – but that would put them too far away to have human-type life on them.

And the other problem is the travel. Sure, Scholz’s Star came close by astronomical standards. But that’s the point. Astronomical. It never came closer than 0.82 light years. Yup, light – the fastest thing you can get – still took eight-tenths of a year to reach it. In everyday terms, that’s 7,800,000,000,000 kilometres. Woah! As I told Elvis, our fastest space probe, New Horizons, would take 16,000 years to cross that distance.

He nodded throughout. Obviously he didn’t dispute it. But I hadn’t addressed his basic point.

‘The problem,’ Elvis suddenly said, ‘is that as a species we humans suffer terrible delusions about self-importance.’

‘Don’t say that too loudly,’ I said ‘you’ll upset people.’

‘What do I care? I live on Mars.’ He crumpled his burger wrapper.

‘Tuesday week?’

‘Yeah.’

Copyright © Matthew Wright 2015

*Well, he says he’s Elvis, anyway. But even if he’s AN Elvis (as I actually suspect) rather than THE Elvis, who cares? He talks sense, which isn’t bad for someone who lives on Mars most of the time and has to hide inside a walrus costume to avoid being mobbed by Elvis impersonator fans.

How Stephen Hawking reconciled the irreconcilable

I finally caught up with The Theory of Everything the other week – an awesome biopic about Stephen Hawking, the British physicist whose life’s goal is to find a theory – a single equation – that explains – well, everything. And what they didn’t mention in the movie is that he’s already made the first big discovery along that path.

The Horsehead nebula, Barnard 33, as seen by Hubble. Wonderful, wonderful imagery.

The Horsehead nebula, Barnard 33, as seen by Hubble. Wonderful, wonderful imagery.

Let me explain. There are two main theories of the universe. Albert Einstein’s ‘General Theory of Relativity’ of 1917 totally explains space-time – the macro-scale universe. Quantum physics, which emerged a little later at the hands of Paul Dirac, Max Planck, Neils Bohr and others, works brilliantly in the micro-world – specifically, scales around a Planck length (1.61619926 × 10-35  metres). But the two don’t play nicely together. Not at all.

So far, nobody’s been able to reconcile them – despite the profusion of hypotheses such as string theory, where the maths work out fine, but where nobody has been able to find any evidence to prove it. (I can’t help thinking this is why Sheldon is a string theorist…)

Finding a ‘theory of everything’ has long been Hawking’s goal; and with Jacob Bekenstein he was the first to discover a way in which both Einstein’s General Relativity and the Copenhagen interpretation of quantum physics could work together. They found that way in 1975, at the extreme edge of the possible – inside a black hole. Here’s Hawking’s original paper, ‘Particle Creation By Black Holes’ Commun. math. Phys. 43, 199—220 (1975).

A bit of explanation first. A ‘black hole’ is actually a ‘singularity’, a mathematical point where the curvature of space-time becomes infinite. The normal laws of space-time – the ones our friend Albert Einstein described – totally fail at that point. Even causality doesn’t apply. As Hawking once pointed out in a lecture, we can’t even imagine what might happen inside a singularity (he suggested a singularity could emit Cthulthu – it wouldn’t violate the laws of physics. I disagree. I can’t even pronounce Cthulthu. I think it would emit Sauron instead.)

Artists impression of a GRB. Zhang Whoosley, NASA, public domain, via Wikipedia.

Artists impression of a GRB. Zhang Whoosley, NASA, public domain, via Wikipedia.

Luckily for us, the everyday universe is shielded from singularities by the event horizon – the point where the escape velocity of the singularity exceeds light-speed. Stuff can fall in. But nothing gets out. Hence the term ‘black hole’. Hawking disputed that. Quantum theory states that particle pairs – positive and negative – are always appearing out of nowhere, then annihilating each other. It doesn’t violate thermodynamics because the net energy outcome is still zero. The effect is known as ‘quantum vacuum fluctuation’.

What I’m about to describe is the heuristic overview – the physics of it is complex and involves some mind-exploding mathematics (‘Bogoliubov transformations’). Basically, Hawking reasoned that if a quantum vacuum fluctuation occurred on the event horizon, there was a chance that one particle, the negative, would be drawn in while the other escaped. They couldn’t annihilate each other, because nothing can escape the horizon. Being negative, the falling particle would reduce the mass of the black hole. Meanwhile the positive particle would escape – effectively as heat – from the black hole.

The result was that ‘black holes’ weren’t actually the black dead ends previously imagined. They were glowing. And they’d eventually evaporate. And THAT is Hawking Radiation.

This also meant that black holes had life limits, and while larger-mass holes had lifespans measured in billions of years, small ones would disappear quickly – which, incidentally, is why nobody’s worried about forming one with a few tens of particles in the Large Hadron Collider at CERN, which is about to be deployed at full power for the first time this year. It’d evaporate in way less than a microsecond. And so Hawking showed that, yes – at least in this extreme case – quantum physics and Einsteinian determinism could play nicely together.

The next question was whether the two could be reconciled in more everyday terms. And that’s been the stalling point. But if anybody can solve it – well, I figure it’ll be Hawking.

Copyright © Matthew Wright 2015

Getting winked at by a mystery star! Really

The latest wow-find from astronomers has snuck up on us by stealth. A small red dwarf star discovered in November 2013 by German astronomer Ralf-Dieter Scholz looked, first off, to be pretty ordinary.

Conceptual picture I made of a red dwarf with large companion using my trusty Celestia installation.

Conceptual picture I made of a red dwarf with companion using my trusty Celestia installation.

It even had a boring name: WISE J072003.20−084651.2, courtesy of being found lurking in data collected by the WISE Satellite. It is estimated to be 19.6 light years distant – in our neighbourhood, as stars go, but not exceptionally close. It has around 86 times the mass of Jupiter, making it a M9.5 class red dwarf, one of the smallest possible.

It is orbited – at the equivalent distance of Venus – by a ‘brown dwarf’ companion, a body with 65 times the mass of Jupiter. This world is warmed to near-luminescence by gravitational compression and – potentially – deuterium fusion, but isn’t massive enough to trigger hydrogen-1 fusion and light up like its star.

Yawn. Red dwarfs are the most common stars around. Proxima Centauri, the closest star to the Sun, is a prime example. In fact, of the 60 stars known within 16.3 light years, 46 are red dwarfs. We’re finding lots in our neighbourhood lately because many are so cool and dim – by stellar standards – they’re invisible even to high-powered telescopes. It takes satellites with sensitive infra-red detectors to pick them up. Brown dwarfs are also appearing to these instruments – singly, or orbiting stars that (wait for it) are often red dwarfs.

Since 2013, though, Scholz’s Star has rung alarm bells. First was its proper motion – the way it tracked tangentially across the sky, relative to other stars. Eric Mamajek of the University of Rochester in New York led a team looking into that, using data collected by the South African Large Telescope and the Las Campanas Observatory’s Magellan telescope in South America. They discovered the proper motion was very slow. But the star itself had very high radial velocity – its actual speed. Around 83 kilometres a second, in fact – four times the usual velocity of stars in this part of the galaxy.

This added up to a star that was travelling fast – but which from our viewpoint didn’t appear to be moving. That’s no paradox – imagine you’re looking up a straight road at a car disappearing into the distance. It’s moving fast, but from where you’re standing, it isn’t moving left or right (‘proper motion’). That’s because it’s moving directly away – and that’s true of Scholz’s Star.

Comparison between stars and brown dwarfs. Not strictly to scale. Public domain, NASA/JPL/Caltech.

Comparison between stars and brown dwarfs. Not strictly to scale. Public domain, NASA/JPL/Caltech.

Mamajek and his team ran 10,000 mathematical simulations to find out how close it had been. And – just announced this month – they discovered that, some 70,000 years ago, Scholz’s Star skimmed past our solar system. With a closest approach of just 0.82 light years – some 52,000 times the distance of Earth from the Sun – it banged through the outer fringes of the Oort cloud, the icy cloud of debris left over from the formation of our solar system, which extends out to a light year or so.

The star was far too small and far too distant to affect the orbits of the Sun’s planets. Here on Earth, the Moon has 2,000,000,000,000,000 times the tidal effect exerted by Scholz’s Star at closest approach. But it will have perturbed some of the the ice-and-dirt clusters of the Oort cloud.  Passing stars are thought to do this every so often, and it’s thought that Scholz’s Star was far from the most serious. Some material will probably have been lobbed sunwards, and will still be on their way in – meaning there will be a small scattering of comets arriving in about 2,000,000 years. Yah, we’re talking about astronomy here – which means having a barrel full of zeroes by your desk.

Did ancient humans see the star? If we draw a circle around the Sun at 100,000 times Earth’s distance and plot Scholz’s Star’s path through it, we find the star took around 10,000 years to traverse that line. Back then it had huge ‘proper motion’ by stellar standards – enough to move across the sky by the angular width of the full Moon in 26 years.

But even at closest approach Scholz’s Star would have been around 11.8 magnitude and thus utterly invisible to the naked eye. But the thing about red dwarfs is that they’re often magnetically unstable – and emit huge flares. In some cases that can increase the brightness of the star, briefly, about 400 times. That would have been enough to make it visible as it tracked through our skies – intermittently. The jury’s out on Scholz’s Star, but Mamajek has speculated that it probably did flare regularly.

Yup, Scholz’s Star was probably winking at us. Which is kind of cool. And begs a question – what would happen if a star came even closer? More soon.

Copyright © Matthew Wright 2015

Why I think Mars One is a really stupid notion

I posted last week about the silliness of trying to colonise Mars on a one-way basis, unless you’re sending Justin Bieber.

Sure, most colonists here on Earth made the trip one-way. But Earth’s way more hospitable. Even Roanoke. You can breathe the air, for a start.

Artists' impression of the Orion EFT-1 mission. NASA, public domain.

Artists’ impression of the Orion EFT-1 mission. NASA, public domain. Eventually, Orion may be part of the system that takes us to Mars – and brings us back.

Mars – that’s another planet. It has red skies and blue sunsets, temperatures that make Antarctica look summery, and surface air pressure about 0.6% that of Earth, though that’s academic because it’s mostly carbon dioxide anyway. Mars also has no magnetic field, which means the surface is irradiated from space. Then there’s the dirt, which the Phoenix lander found was saturated with naturally-formed perchlorates. Know what perchlorate is? Rocket fuel. It’s nasty stuff, it’s toxic, and the chances of keeping the habitat clear of it after a few EVA’s seems low.

The biggest problem is that nobody’s been there yet. There’s bound to be a curve ball we don’t know about. It’ll be discovered the hard way.

That was the Apollo experience forty years ago. It turned out lunar dust is abrasive and insidious. As early as Apollo 12, astronauts found dust in the seals when they re-donned their suits for a second EVA – moon-walker Pete Conrad reported that ‘there’s no doubt in my mind that with a couple more EVA’s something could have ground to a halt’. All the later Apollo astronauts hit it; leak rates soared in the suits as dust worked its way into the sealing rings.

I think it’s safe to say something of equal practical difficulty will be discovered about Mars, one way or another. Not good if you’ve just arrived – permanently. Besides, what happens if someone gets needs a hospital now? Or is injured? Well, that’s a no-brainer. You can imagine the colony consisting of a cluster of grounded Dragons with a row of graves next to it.

Cut-away of the modified Apollo/SIVB 'wet lab' configuration for the 1973-74 Venus flyby. NASA, public domain, via Wikipedia.

Cut-away of the modified Apollo/SIVB ‘wet lab’ configuration for the 1973-74 Venus flyby. NASA, public domain, via Wikipedia.

Mars One plan to send more missions every two years, each with four colonists to join the happy bunch. If they’re alive. My money says they won’t be. This is Scott of the Antarctic territory – high-tech for the day (Scott even had motorised tractors) but still gimcrack.

The main reason we’ve not gone there yet, despite space agencies making serious plans since the 1960s, is cost. Manned interplanetary fly-bys were (just) within reach of the hardware built for the Moon landings – and until the Apollo Applications Programme was slashed to just Skylab, NASA was looking at a manned Venus flyby for 1973-74, using Apollo hardware.

Composite panorama of Mars. Not going to be seen by the 2018 expedition, as they'll fly past the night side. NASA, public domain.

Composite panorama of Mars. NASA, public domain.

Unfortunately, stopping at the destination, landing on it, and all the rest was another matter. It was easy to accelerate an Apollo CSM and habitat module into a free-return Venus or Mars trajectory; no further fuel was needed, it’d whip past the target at interplanetary velocities, and the CM could aerobrake to a safe landing on Earth. But stopping at the destination, landing and then returning home? In rocketry – whether chemical or nuclear-thermal (NERVA), the two technologies available until recently, mass-ratios are critical.

Mass ratio is the difference in mass between an empty and fuelled rocket at all times, and fuel takes fuel to accelerate it. It’s a calculation of sharply diminishing returns, and the upshot for NASA and other Mars mission planners in the twentieth century was that a practical manned landing mission was going to (a) require a colossal amount of fuel, and (b) would still transit by low-energy Hohmann orbit requiring a 256 day flight each way, meaning more life support, which meant more fuel (see what I mean?).

Some plans looked to refuel the system from Martian resources, but that had challenges of its own. Either way, the biggest challenge in all Mars mission schemes was the first step, lifting the Mars ship off Earth into a parking orbit. No single rocket could do that in one go, meaning multiple launches and assembly in orbit, raising cost and complexity still further. With figures in tens and hundreds of billions of dollars being bandied about, and no real public enthusiasm for space after Apollo, it’s small wonder governments were daunted.

ROMBUS in Mars orbit: Mars Excursion Module backs away ready for landing. Public domain, NASA.

Conceptual art of Philip Bono’s colossal ROMBUS booster in Mars orbit: Mars Excursion Module backs away ready for landing. Public domain, NASA.

My take – which is far from original to me – is don’t try going to Mars now. Focus on building a space-to-space propulsion system that offers better impulse than chemical or nuclear-thermal motors. Do that and the 256-day trans-Mars cruise – which is what drives the scale and risk of the mission, including problems with radiation doses in deep space – goes away. One promising option is the Variable Specific Impulse Magnetoplasma Rocket (VASIMIR), a high-powered ion drive that might do the trick if it works as envisaged. Another is the FDR (Fusion Driven Rocket). Current projections suggest Earth-Mars transit times as low as 30 days.

Of course, if your drive won’t light when you need it to slow down, you’re on a one-way trip out of the solar system. But hey…

Maybe we should send Justin Bieber on that first VASIMIR mission, just in case…

Copyright © Matthew Wright 2015