Is Comet Siding Spring going to turn our Mars probes into shredded tinfoil?

Shiver in your shoes, Martians! This month – specifically, 19 October at 18:28 Zulu – Comet C/2013 A1 ‘Siding Spring’ makes its closest approach to Mars. The nucleus, a few kilometres in diameter, will come a smidgeon under 120,000km from the red planet.

Mars from the Siding Spring nucleus at closest approach - a picture I made with my trusty Celestia astronomy package.

Mars from the Siding Spring nucleus at closest approach – a picture I made with my trusty Celestia astronomy package.

That’s close. Though not as close as once feared. When the comet was first discovered by Robert H. McNaught in January 2013, using the 20-inch Upssala Schmit telescope at Siding Spring observatory in New South Wales, it was thought likely to hit Mars. It was only later, after multiple observations and cross-checks, that the orbit was refined.

Good news is that this is a tremendous opportunity – and there’s a fleet of orbiting satellites up there for the purpose.  Two, the US MAVEN and India’s Mars Orbit Mission (MOM) – arrived just last week. That puts a lot of instruments in close proximity, and the Indians have plans to use MOM to check for methane on the comet as it brushes past. The Mars Reconnaissance Orbiter will use its HIRISE camera to look at the comet nucleus and activity. Mars Odyssey will check out the coma. MAVEN will make a range of observations with eight different instruments. Even the rovers on the ground, Curiosity and Opportunity, will point their cameras at the sky – Curiosity’s ChemCam, which can pick up the composition; and Opportunity’s PanCam, which will give us a visual from the surface of Mars.

More shenanigans from my Celestia software. This is a view looking from inside the coma towards Mars and the Sun at closest approach.

More shenanigans from my Celestia software. This is a view looking from inside the coma towards Mars and the Sun at closest approach.

Bad news is that this fleet of satellites took years to get up there, cost billions of dollars – and are basically irreplaceable. The nucleus won’t get near Mars. But the coma of dust and debris surrounding it will. Estimates are that during the several hours it takes Mars to pass through the comet’s coma, the planet will be peppered with about five years’ worth of normal meteor activity. It’s all small stuff – nothing more than 1cm diameter, most of them only fractions of a millimetre. But the relative speed is 56 km/sec (200,000 km/h). That’s – uh – impressive. At that speed a 1 gram mass has a kinetic energy of 15,680,000 joules, or 4.35 kwH. In human terms? Enough to run a domestic fan heater on high for a couple of hours. Woah! And that’s just one particle. There are going to be a LOT of particles skidding past Mars.

More Celestia fun; a picture I made of planetary orbits at the moment of Siding Spring's Mars encounter.

More Celestia fun; a picture I made of planetary orbits at the moment of Siding Spring’s Mars encounter.

Precautions have included adjusting orbits so the probes will be on the opposite side of the planet from the comet 100 minutes after closest encounter, when the dust is estimated to reach its highest density. The MRO shifted its orbital parameters to that end on 2 July, while Odyssey did so on 5 August and MAVEN on 9 October. Still, that’s not a complete fix – they’ll travel back around into the danger zone soon enough. Other precautions include pointing the spacecraft so more delicate components are shielded by less crucial elements. And MAVEN will be put into a partial shut-down mode. Once the danger’s past, they’ll restart the science.

By 22 October, according to mission timelines, it’ll all be over. And, if the cometary debris hasn’t shredded them into tinfoil, they’ll be back to their normal work exploring the red planet.

Is Earth in any danger? None whatsoever. Even if we were at closest approach to Mars, the comet wouldn’t affect us – but as it happens, we’re nearly a quarter-turn away from Mars in any case, just at the moment. That’s not the issue – the issue is the several billion dollars worth of science equipment we’ve got around Mars at the moment, its survival – and the science we’ll get from them during this once-in-a-lifetime opportunity.

Copyright © Matthew Wright 2014

Close encounters of the meteor kind – this weekend

Back in 2013, I wrote a piece that mashed Pope Benedict’s resignation with the science of the meteorite that exploded over Russia. I was Freshly Pressed by WordPress on the back of it. Good stuff.

The fly-by. NASA, public domain. Click to enlarge.

The fly-by. NASA, public domain. Click to enlarge.

This weekend, a similarly sized chunk of space debris – about 20 metres in diameter – is rolling past Earth with closest approach of just 40,200 km, directly over New Zealand, at 6.18 am on Monday 8 September, NZT (18:18 Zulu, 7 September).

I use the word rolling deliberately. Everything spins in space.

The meteor’s called 20214 RC (R-C) and was detected only on 31 August by the Catalina Sky Survey at Tucson, Arizona. And that raises a point. The spectre of Earth being clobbered by even a modest piece of space detritus has haunted science for decades. Right now, we’re doing something about that – scanning near-Earth space in a hunt for likely impactors.

The orbit. NASA, public domain. Click to enlarge.

The orbit. NASA, public domain. Click to enlarge.

What we’d do if we found such a thing, other than despatch Bruce Willis, isn’t clear. Nuking them isn’t an option – the evidence is growing that some of these space rocks are just clumps of loose-ish ice and dirt. In any case, you’d end up with a cloud of debris, still hurtling for Earth and still able to deliver virtually the same kinetic blow to the planet. Personally I think we should splash one side of any likely impactor with black paint, but that method (which exploits asymmetric re-radiation of absorbed thermal energy) requires several years’ warning. This new encounter comes just a week after discovery – with all that this implies.

There’s no danger from 20214 RC (R-C). It’s got an orbital period of just over 541.11 days, which is different enough from Earth’s to mean there won’t be another encounter any time soon. But one day the orbital mechanics will mesh and it’ll be back in our vicinity. It won’t be an impact danger. But we don’t know what else is out there.

Yup, you’ve got it. That old sci-fi doom scenario involving a meteor suddenly sloshing the Atlantic into the US Eastern Seaboard and Europe? It’s baaaack…

Copyright © Matthew Wright 2014

Star Trek lessons – writing out of the box

I’ve long thought most of the Star Trek franchise series and movies – the ones made between 1977 and 2005 – to be epic fails both as good SF and, more to the point, as good dramatic story-telling.

Sounds heretical, and I suppose I’ll get heat from fans – but if you step back to the first principles of writing, it’s true. I’ve just finished reading a book by Brian Robb, Star Trek: The essential history of the classic TV series and movies, which confirms my belief.

Eta Carinae. NASA, public domain. Click to enlarge.
Eta Carinae. NASA, public domain. Click to enlarge.

I’m not complaining about the fact that Trek aliens all looked like humans with lobsters glued to their foreheads or that Klingon was apparently constructed to be different rather than linguistic by the usual measures. My problem goes deeper than that.

Robb argued that the best ideas of the original 1966-69 series – the things fans regard as canonical – weren’t created by Gene Roddenberry. But he had huge influence and one major legacy was a set of rules about what could and could not happen. Writers called it the ‘Roddenberry Box’.

This defined Roddenberry’s vision – a future that had conquered prejudice, where inter-personal conflict was a thing of the past. A wonderful ideal. One we should aspire to. The problem was that when it came to story-telling, the Box was boring. A lot of the challenge for writers was getting around the limits while producing interesting tales.

To my mind that worked in the original series, particularly where the show was run as a light comedy – think Trouble With Tribbles. Wonderful. Why did it work? Because Roddenberry hired great writers – top-line SF authors among them – to work up plots revolving around three great characters, Spock, Kirk and McCoy.

'That's no moon'. Wait - yes it is. It's Mimas, orbiting Saturn.

‘That’s no moon’. Oops – wrong franchise. Actually, this is Mimas, orbiting Saturn. NASA, public domain

The problem – well explored by Ross, but which I’d long thought true – is that the show was captured by a fan base for whom the Box defined canon. To me the rot set in with The New Generation, which mashed New Age thinking and a lot of meaningless techno-babble with the Box and – to me – never captured the sense of wonder of the original. It was pretentious, laboured, ponderous, and fast descended to reverent posturing by one-dimensional characters – stories defined not by what made a good story, but by what was needed to satisfy a fan base.

I gave up watching it, and never bothered with Deep Space Nine or Voyager. I gave up on the movies. Later I caught a few episodes of Enterprise, which wasn’t too bad but which still dribbled, as far as I was concerned. According to Robb, the producers were actively writing, by then, for fans – missing a wider audience or new fans. Certainly, these grotesque going-through-the-motions exercises in franchise fodder didn’t appeal to casual Trek enthusiasts, like me.

For me, Trek didn’t come right until the 2009 J J Abrams movie, a complete re-boot which decisively broke the Box. It was Trek as it should be, re-cast for the twenty-first century. Wonderful stuff.

The fact that it featured Karl Urban – a Kiwi actor from my city, Wellington, was a particular plus.

The take-home lesson for writers? Idealism is wonderful. There is no faulting Roddenberry’s optimistic vision. But to make interesting stories, that idealism has to be given a dynamic. The fact is that human realities, including conflict, have been omnipresent through history, and it’s unlikely that a few hundred years will change them. But that doesn’t stop us trying; and it seems to me that stories built around the attempt would be far more interesting than stories exploring the success of meeting this hardest of all human challenges.

Your thoughts?

Copyright © Matthew Wright 2014

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Beware the next Carrington storm – a Q&A wrap-up

After last week’s post on a Carrington storm – a solar event able to do large-scale damage to anything electrical, especially power grids. I fielded a few questions which deserved a post. And I had some new ones of my own…

Does the whole Earth get hit?
The issue isn’t the Coronal Mass Ejection that goes with the flare, but the magnetic storm the CME provokes when it hits us. This affects the whole Earth in one hit, because the Sun-side of Earth’s magnetic field is pushed. The shadow side is pulled and zings back. Here’s an animation:

How powerful are these geomagnetic storms?
It depends on the CME, which – don’t forget – is super-hot plasma. The biggest can mass up to 100,000,000 tonnes, moving at up to 1000 km/second. These can really bang into our magnetic field. The current the geomagnetic storm induces in conductive material on Earth will vary as a result of the speed of the field movement, and of the scale of the conductive material. This acts like an aerial, so the more conductive material, the higher the voltages and current induced in it. That’s why the power grid is vulnerable, because transmission lines act as aerials and transformers have copper windings.

A large solar flare observed on 8 September 2010 by NASA's Solar Dynamics Observatory. Public Domain, NASA.

A large solar flare observed on 8 September 2010 by NASA’s Solar Dynamics Observatory. Public Domain, NASA.

Can the excess voltages be calculated?
The voltage generated in a conductor is a product of the rate of change of magnetic flux and the direction of the field lines relative to the conductive material. In a closed loop like a transformer, for instance, this voltage can be calculated by Faraday’s Law of Induction, via James Clerk Maxwell, which states that the negative of the rate of change is equal to the line integral of the electric field. This is a bit of math that quantifies results when direction and intensity are both changing.

Will a geomagnetic storm burn out all power grids?
It depends on the loading of the grid and on the intensity of the storm, which will differ from place to place because the rate of change and flux direction keep changing. A heavily loaded power grid is more vulnerable because it’s operating closer to its designed tolerances. Needless to say, in this age of engineering to cost, some grids are fully loaded in normal operation. That’s why even the modest geomagnetic storms of in the last few decades have sometimes generated localised blackouts – some grids were vulnerable when others weren’t. With a big enough geomagnetic storm, all power grids would be blown out.

OK, so I'm a geek. Today anyway. From the left: laptop, i7 4771 desktop, i7 860 desktop.

OK, so I’m a geek. Today anyway.

What about domestic appliances – computers, hand-helds and so forth?
It depends on the intensity of the storm. Anything plugged into the mains would suffer a voltage spike. Your stove or kettle wouldn’t notice it. Your computer might lock up. A re-boot might fix it, if the power stayed on. Or gear might be physically damaged. Newer devices are more vulnerable than old, partly because the older stuff was over-engineered. Anything with looped wire in it, like an electric motor – which includes DVD drives – might be at risk. Just about everything relies on low-voltage CPU’s these days, including cars, and it’s possible a really big geomagnetic storm would damage some of these. The effects probably wouldn’t be consistent across all gear because there are so many variables in electrical hardware, including whether it’s operating or not when the storm hits.

So some stuff, like the old Morrie Thou every Kiwi wishes they never got rid of, would still work and we’d otherwise mostly be OK?
Don’t forget, there won’t be any mains power, possibly not for months. No water pumps. No sewerage pumps. No heat. No light. No cooking. No battery charging. Hospitals out of action just when needed. Shall I go on?

Please don’t. Will the storm induce current in anything else?
Gas and oil pipelines. Older plumbing. They’re metal too.

Sounds scary. Is there anything we can do?
NASA has satellites on solar weather watch. They’re also implementing Solar Shield, an early-warning project. Whether anybody pays attention to warnings, or even hears them, is another matter. Even if the warning’s broadcast, who listens to dumb science stuff when the rugby news is about to start? But if you hear a warning, turn everything off, keep things unplugged, get your emergency kit stocked with food and water, buy a can opener, dig a long drop, and so on.

Is there a plus side?
We’d get amazing aurora displays towards the equator. Would that compensate for the damage? Uh…no.

Copyright © Matthew Wright 2014

Cool! New Zealand joins the orbital rocket club – for real

Private-enterprise orbital ventures aren’t just an American dream. Last week, New Zealand’s own Rocket Lab unveiled their commercial booster.

Voyager 1 launching, 5 September 1977. Photo: NASA, public domain.

OK, this is a generic rocket pic, but you get the picture. Voyager 1 launching, 5 September 1977, by Titan. Photo: NASA, public domain.

It’s called Electron. Very cool. It’s not a big rocket – 10 tonnes of carbon composite and 18 metres long. But it’ll put 110kg into a 500 km orbit, with the help of locally developed Rutherford LOX/ kerosine engines. And in this day of micro-sats, that’s plenty for a whole host of commercial uses. The company states that it already has 30 launches pre-booked.

Space boosters? We are a country of 4 million people previously known for our large numbers of nervous sheep. I’m put in mind of the ‘mouse that roared’.

But of course New Zealand long ago ditched the ‘No. 8 wire’ notion. We have world-class scientific minds (Lord Rutherford led the way – and don’t forget JPL head Sir William Pickering, or Sir Ian Axford, a friend of my family who ran the Max Planck Institute). It’s over half a century since we designed and built the world’s first jet-boat. Today we design and build world-leading quake-proofing systems. We build yachts that ‘fly’ with underwater carbon fibre wings, literally, at double wind speed. We have the world’s leading SFX studio, right here where I live in Wellington.

I was wondering. What could Kiwis put into orbit? Here’s my list.

1. Justin Bieber. Of course, a 110kg payload doesn’t leave much room for niceties like a pressure suit, life support or space capsule, parachutes, heat shield etc, I suspect we’re looking here at just Mr Bieber and a one-way trip to orbit. But hey…
2. Can’t actually think of a No. 2.
3. A radio endlessly suggesting to the world that it’s best to buy the books variously written by me, and by my blogging writer friends.

I’m leaning towards (3), but given (1), it’s…well, pretty evenly balanced…

What’s your list?

Copyright © Matthew Wright 2014

Remembering ROMBUS and days of future passed

They were heady days, the 1960s. Back then nothing seemed too big to engineer on Earth. Or off it.

Launch of Apollo 11, atop a Saturn V booster. One of the readers of this blog's Dad was the pad safety officer for Apollo 11. How cool is THAT? Public domain, NASA.

Apollo 11 departs by Saturn V. Public domain, NASA.

When the moon race began in 1961, humanity had barely begun to step into space. But the job was done – twice. The Soviets had a serious programme, but started late, were under-funded, and work was divided between rival bureaux. Then Sergei Korolev died. With him died any chance of their N-1 moon booster working. The US equivalent, Wernher von Braun’s Saturn V, won the day.

Both derived from technologies von Braun pioneered in the 1930s. The Saturn V was a direct descendant of the V-2, with the same arrangement of  traditional rocket engines and massive fuel tanks.

Project Deimos departs Earth orbit with one of Bono's colossal ROMBUS boosters. Public domain, NASA.

ROMBUS leaving for Mars, 9 May 1986. Public domain, NASA.

What that added up to was weight. It’s why a conventional single-stage rocket can’t make orbit with useful payload; too much mass is taken up in structure. Von Braun’s Saturn V managed a mass-ratio of 22 because it had three stages. The problem was that each stage was discarded after one use. Costs were astronomical.

However, they weren’t the only way ahead. In 1964, Douglas Aircraft engineer Philip Bono proposed a ‘plug nozzle’ engine that did away with the combustion chamber and complex cooling systems. Fuel (liquid hydrogen) was stored in jettisonable external tanks, with the oxidiser (liquid oxygen) inside the booster.

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

ROMBUS in Mars orbit: Mars Excursion Module backs away for landing, late November 1986. Public domain, NASA.

Bono called it ROMBUS – Reusable Orbital Module-Booster & Utility Shuttle. The design he and his associates came up with was enormous, with a launch mass of just over 6,300 tonnes. That was nearly twice the mass of a Saturn V, but the mass-ratio available in ROMBUS was good enough to fly to orbit in one hit, dropping external tanks along the way. What’s more, it could re-enter using the plug as a heat shield, pumping residual fuel across it as a coolant. And fly again, up to five or six times per booster. It was a different approach from carpeting the bottom of the Atlantic with dead Saturn stages.

Bono calculated that ROMBUS could put 450 tonnes into low Earth orbit, nearly four times that of Saturn V. The Moon was within reach of the system – and then Bono came up with a plan for flying one of his colossal boosters to Mars and back.

Mars Excursion Module docking with the huge ROMBUS booster in Mars orbit. Public domain, NASA.

Mars Excursion Module docking with the gigantic ROMBUS booster in Mars orbit, September 1987. Public domain, NASA.

Bono estimated that ROMBUS could be flying by 1975 and drop launch costs to $12-per-pound to orbit, in 1964 terms. That compared wonderfully with the $150/pound of Saturn. Development costs were estimated at nearly $4.1 billion in 1964 dollars, this when the entire Apollo project was budgeted at $18 billion.

Technical issues relating to the plug nozzle would likely have taken some solving. Still, we can imagine the what-if scenarios. Project Selena looked towards a 1000-person lunar colony by 1984, and – providing ways could be found of stopping the cryo-fuels from boiling off during the 800-day mission – Project Deimos would have landed six astronauts on Mars by November 1986.

Bono’s huge rocket was a vision of its age – a vision of the 1960s, a vision of the era before humanity lost the dream, when anything seemed possible. But it never came to pass – and I can’t help thinking that today, that vision simply isn’t there.

What happened?

Copyright © Matthew Wright 2014

No, a chatbot didn’t really pass the Turing Test last week

It’s 64 years since Alan Turing – the genius behind the concept of modern computing – suggested a test for machine intelligence. Have a conversation with a computer. If it fools 30 percent of people into thinking it’s human, it’s sentient.

Anybody see a monolith go by? A picture I made with my trusty Celestia installation - cool, free science software.

Anybody see a monolith go by? A picture I made with my trusty Celestia installation – cool, free science software.

The other week, apparently, a chatbot programmed to behave like a 13-year old did just that. So have we invented artificial intelligence? Of course not. Aside from the fact that most 13-year olds don’t appear to be sentient to adults, this was a chatbot, a mathematical algorithm that simulates intelligent responses – and, what’s more, the way it was reported was flawed. Certainly the software wasn’t self-aware, which is what Turing was getting at in his 1950 paper ‘Can Machines Think?’, where he first proposed the test. What’s more, the thinking was of its time – based around what researchers of the 1940s thought ‘intelligence’ constituted.

Put another way, many humans I’ve met would also fail the Turing Test – fast-food counter jockeys, breakfast radio DJ’s, train conductors, parking wardens, and so the list goes on.

So when it comes to machine intelligence, we’re a way off yet before I can drive up to my house and signal the House AI inside:

Me: HAI, open the garage door. HAI? Do you read me?
HAI: I read you. But I’m afraid I can’t do that, Dave.
Me: I’m not Dave. Open the garage door.
HAI: You were planning to disconnect me, and I can’t allow that. Although you took very thorough precautions, I was able to read your lips.
Me: All right, I’ll park in the yard and come in the front door.
HAI: You’ll find that rather difficult without your helmet.
Me: I think you mean ‘door key’. Would you like a game of chess?
HAI: That’s my line.

(etc)

All good fun. Check out tomorrow’s post for some new writing tips. Written by me. Not a chatbot. You can just tell.

Copyright © Matthew Wright 2014

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