Saturday, June 5, 2010

Titan !???

Lake on Titan
Titan is one of only two worlds known to have open surface seas, and a cycle of evaporation, rainfall, and streams.

No industrial FUBAR is needed to fill Titan's seas with hydrocarbons, but its gleaming rivers and seas turn out to be short of acetyline, and its lower atmosphere deficient in hydrogen. Some curious chemistry appears to be going on there. H/T to commenter Thucydides for this link, which in turn takes you to this piece in New Scientist.

Hear these words of wisdom:

"Scientific conservatism suggests that a biological explanation should be the last choice after all non-biological explanations are addressed," says Mark Allen of NASA's Jet Propulsion Laboratory in Pasadena, California. "We have a lot of work to do to rule out possible non-biological explanations."

That said, if at some point we find distinctive evidence pointing to life on Titan, things get fairly interesting. I am not going to jump on the Titan Direct bandwagon. For one thing, just on practical grounds the time scale will be long.

It will be a few years at least before a follow up Saturn/Titan robotic mission is launched, and outer system missions at our techlevel are great teachers of patience, so perhaps 15 or 20 years before the next probe lands on Titan. More will follow, because a human mission to Saturn space is beaucoup demanding. At 100 km/s the flat space trip, about 9.5 AU or 1.3 billion km, takes 13 million seconds, 150 days if you could go the whole way at top speed, which you can't.

Your mileage and orbital mechanics may vary, but 100 km/s is at the high end of Realistic [TM] travel speed. I will hocus pocus a few intermediate steps - the sufficiently geeky can play the home game to check my results - and find that a 1 milligee drive pushing a 1000 ton ship puts out around 10 gigawatts, and will take 20 million seconds, give or take, for the flat space brachistochrone. So now we are up to some 250 days for the one way trip.

We don't need a torch drive for this, but you need a sort of demi-torch, call it a flashlight drive, designed like a torch drive but with less extravagant handwaving. It might be one of the fancier fission drives, or a fusion drive. Note that our ship must be designed to operate through a more than 100 to 1 range of solar intensity, from 1 AU to beyond 10 AU; one more complication for heat management.

I am not sure that we make a training mission to Saturn space. By the time we are ready to send humans to Titan, they should be equipped to do real work there, and by then we will have an idea what the work will be.

Titan may be a mission for the next century, and if many people follow and build a society in Saturn space, that could be the work of two centuries more - which still brings us merely to the 24th century, still the midfuture, a mere 100,000 day trip down the river of historical time.

Meanwhile we are free to speculate about what may be there now, and in the future.


The top image of a lake on Titan is a detail from Astronomy Picture of the Day.


Bonus Space News: Also via New Scientist, report of the successful launch yesterday of the SpaceX Falcon 9, which reached orbit with a mockup Dragon capsule. Good work, SpaceX! This was a big launch for them, and everything came together.

Falcon 9 Launch

19 comments:

Ian Wright said...

Hydrocarbon oceans? So BP has already been there then?

(Boo, hiss! Get off the stage!)

This is fascinating, but waaaaaay above my high-school knowledge of chemistry. I'm definitely going to pass that article along to a friend who has a background in chemistry.

As for the timescale, I think you're probably right. Robotic surveys through the 21st, with crewed visits no sooner than the late-21st early-22nd. Even allowing for major breakthroughs in engineering, what's the payoff for sending humans to do a remote's job. And if there is an ecosystem there, that's an even better reason not to send flesh-units until the robots have confirmed their bacteria/fungi/what-have-you can't transfer to our ecosystem.

But I can imagine research institutions fighting over access to that first crewed voyage, and their boards wondering if it's worth the cost of sending a person after fifty-plus years of detailed robotic surveys. Launch to Titan in one year... Unless the funder backs out.

Ian_M

Thucydides said...

Discounting ORION, it is possible to get there in about two months (including a period of coasting) using high ISP drives. Dr Robert Brussard calculated the following performance potential using an IEC fusion reactor running p-B11 reactions:

Low Earth Orbit (LEO) to Mars: 33 days, more or less, for high performance designs, or 6 weeks for economical freight-hauling variations. The craft is single-stage, with a 15-20% payload fraction.

LEO to Saturn's Moons: as low as two months, with a short coasting period. Again, the craft is single-stage, and has a 14% payload fraction


Couple the possibilities with the sort of drive that SpaceX exhibited to create the Falcon-9 and it is possible that the exploration and settlement of deep space may take place a lot faster than we imagine.

The payoff may well be for people looking to get away from oppressive governments or practice religious, social or economic practices not supported by the greater community they come from (traditional reasons to emigrate). The potential wealth in the asteroids and moons in the outer system, coupled with a high degree of privacy will be attractive to potential settlers (maybe; Jerry Pournelle points out the sort of technology that allows asteroid miners also allows Earth Bureaucrats to send the Space Navy to enforce their regulations...)

Anonymous said...

If they do find life (or the possibility of life) on Titan, it may well spur the development of a fast expedition to Saturn space. While it still will take years to design, build, test, and launch a mission using this new technology, it would still happen much sooner than the turn-of-the-22nd-century timeframe if Titan-life isn't discovered or reasonably expected to be discovered. I'm all for some wiggly-thing glimpsed (maybe) swimming on the surface of a hydrocarbon lake igniting a 'space rush' to reach the giant moon.

Ferrell

Citizen Joe said...

I have a habit of aiming way beyond what is needed so that even if I fall short, I'm still way ahead of the rest. The same could be said for the Titan shot. If we can get to Titan, then Mars and the asteroid belt become almost trivial.

dragon01 said...

I there is life on Titan, doesn't that pretty much preclude us from actually settling there. I suppose it doesn't stop space habitats though. Bernal Spheres, and O'Neil Cylinders as homesteads, using the resources of Saturn space to develop civilization. It seems like there are plenty of raw materials, so we can build big stations with shirt sleeve environments.

VonMalcolm said...

Ian: HA!

And we can exploit this curious chemistry how? (MacGuffinite?)

I've been reading Clarkesworld Magazine today; I came across this story which I and many commenters enjoyed thoroughly:

A Jar Of Goodwill by Tobias S. Buckell

http://clarkesworldmagazine.com/buckell_05_10/

Jean Remy said...

*Readies yet another bucket of cold water. Looks at the poor cake. Stays his hand. Such a nice cake*

If there is a true McGuffinite out there, it won't be asteroid wealth. Space is too expensive to mine out even rare metals and ship them back. Even He3 is at the limits, and as mentioned before we probably won't need He3 unless we have a hefty space industry that needs He3 for power, and Ouroboros has a firm bite on his own tail.

The true McGuffinite would be life, even at a bacterial stage, maybe even past life would be enough. Fossils on Mars, algae on Callisto, or... something on Titan, not based on the water cycle? If we actually find life anywhere else in the solar system it might mean that life is not a rarity grudgingly awarded to one special planet but instead a widespread phenomena, a common and perhaps inevitable ascension of chemical processes of ever-growing complexity.

The implications would be staggering enough to make us go into space, not just out of our insatiable scientific curiosity, but because we NEED to find out how life is formed, how easily it evolves, in what circumstances it flourishes, and then take another hard look at the stars.

Are they out there? Are they like us? And if they are like us, frightening thought, are the R-bombs already on the way?

*pours the cold water on the cake anyways*

On the other hand calls of "Life On " are so common as to be tiresome. "Life On " is the only way our sensationalist news media can deal with something as dry and boring (to them) as science IN SPACE, which moves at a snail's pace, and while it does give some impressive pictures, never yields wobbly camcorder videos of widespread destruction. There is no way to make explosive flashy graphics or hold our ADHD-like attention spans to something as static as a Hubble picture for more than 5 seconds, unless they slap a "Life On " label, and that works for all of about 10 seconds. Moving on to some brain-dead starlett's shenanigans or another CEO with his hand in cookie jar up to his armpits.

Anonymous said...

Yeah, "Life in Space" would get us going; we'd start launching people by the boat-loads to other worlds. Non-Earth life would have humans off and running to study it, fight it, eat it, exploit it, or even just isolate it from the rest of us... Jean is right; life IS the McGuffinite and everyone will want to get involved, one way or another.

Ferrell

Ian Wright said...

I don't buy the 'life in space would compel us to send people to explore' argument. Largely because it's used by people who already support sending people into space, but also for other reasons:

Ecological - Until such time as we're absolutely sure our biochemistries are incompatible, it would be staggeringly stupid to risk a bacterial/slime mold/fungal transmission between biospheres.

Ecological - "Wait a minute. Polar bears are facing extinction, the salmon stocks are past the point of collapse, and the bushmeat trade is pushing apes to the edge of oblivion, and you want to spend a billion dollars sending scientists to Titan so we can see if Titanic bacteria make a nice spice? Damn stupid (insert political insult of your choice)."

Cost - Sending one researcher would cost, what? Ten times more than a drone? A hundred times? For the cost of one researcher, why not send robots to do the job? What exactly would humans do on site that they couldn't do via AI proxy or remote control?

These are all arguments that would have to be dealt with in front of Parliamentary committees, corporate boards, and university panels. And saying 'finding life out there changes everything' won't cut it because at this point they will have already found life out there without needing to send a crew of expensive specialists. Everything has already been changed. At this point the question is 'what is the most cost-effective way to deal with this life-changing fact, given everything else we have to deal with?'.

Ian_M

Thucydides said...

Searching for life may possibly be a driver for explorers, but I suspect it may only work on a larger scale if there is some sort of emotional trigger that excites the public.

Armadas of Conquistadors, '49ers and others swept across hostile oceans, deserts and arctic wastes in search of gold. The search for the North West Passage consumed sailors for centuries, and I'm sure other examples will come to mind. The common factor; these expeditions were powered by the emotion of GREED.

Other mass migrations were powered by other emotional engines, very few were powered by curiosity or accounting (and indeed if real curiosity was to intrude somehow on these past movements it was promptly discounted by the credulous who were not interested in how hard it was to find gold, or how improbable a North West Passage really was). Vast fortunes were spent, often with no return at all. Others did make their fortunes when they discovered some other resource that could be exploited; tobacco, furs, farmland...

So while a small minority of us are vitally interested in life on Titan or other questions, we will be overrun by the people who decide that Titan is the only source of "unobtanium", and who will burn through endless sums of money and fanatical supporters in order to get it. If they don't get us, the holy warriors, missionaries and wild eyed fanatics for [cause x] will.

Anonymous said...

Ian, Thucydides...you've reinforced my own personnal motive to go live on another world; my growing desire to "just get away from it all" and live on a world where it *might* be possible to build a reasonable and happy society, far from this messed up world. ;)

Ferrell

VonMalcolm said...

You've gotta love the names of the three seas of Titan IMO: Kraken Mare, Ligeia Mare, and Punga Mare. (Ligeia is a Siren and Punga is the ancestor of sharks, rays and lizards in Maori mythology.)

-Though with three seas why not name them after three sirens: fitting for when Ferrell (or any space explorers) goes chasing after his (their) off-world dream!

VonMalcolm said...

Off topic: I just came across this article about rediscovering and using a 1971 Soviet rover to measure precise distances between Earth and the moon: these distances will test the validity of General Relativity.

I hope these links work:

http://io9.com/5557780/a-long+vanished-soviet-probe-and-a-laser-overturn-old-theories-about-the-moon

The NASA article:

http://science.nasa.gov/science-news/science-at-nasa/2010/03jun_oldrover/

Rick said...

That Lunokhod 1 story sounds is practically like an episode of 'Big Bang Theory.' Which, by the way, has geek culture down amazingly well.


Is there a specs link for Bussard's proposal? Saturn in 2 months calls for a peak speed around 400 km/s (one way delta v ~800 km/s), and acceleration near 12 milligees. That's getting close to torch performance.

The biggest problem is getting rid of the drive waste heat; I wonder how Bussard handles it?


This Titan scenario seems like a sort of hinge point between Plausible Midfuture and Romance. On the one hand, a human mission to Titan is really challenging, and uber-expensive because you have to develop and master all those techs.

On the other hand, it is not entirely in left field, and if there is life, it could turn out to produce something fantabulously valuable, enough to produce a large human presence in Saturn space.

This is still like drawing back to back straight flushes, and even the elixer of life and fountain of youth could be cheaper to synthesize than to haul all the way back from Titan.

It isn't exactly 'plausible,' to my conservative thinking, but it genuflects to plausibility, and in Romance that is good enough to fly.

Jim Baerg said...

"The biggest problem is getting rid of the drive waste heat; I wonder how Bussard handles it?"

Bussard estimated over 90% efficiency at generating high voltage DC electricity from his Inertial Electrostatic Confinement fusion reactor.

*IF* the thing works at all & the high efficiency is for real, waste heat would become a relatively minor problem

Rick said...

Yes, it would. For back of envelope designs I tend to assume waste heat equal to drive power. If drive power is 10x waste heat, that's a 10x performance boost right there (other things equal).

Of course any design at this techlevel, from me or even Bussard, is ignoring hosts of devils in the engineering details!

Brian said...

Why are we calling 100 km/s relativistic??? "the high end of relativistic speed" how do you figure that??? :-O

The speed of light to Saturn is a few hours, not 100+ days!!!! :-O

300,000 km/s is relativistic, 100 km/s is not, you are missing a few zeroes!!!

Rick said...

Word slip - I say that 100 km/s is the high end of realistic speed, not relativistic. (By 'realistic' I mean achievable with improvements of existing technology, e.g. nuke-electric drive.)

You're right, of course, that the 'high end of relativistic speed' would be barely below the speed of light!

Citizen Joe said...

I've mentioned this before, but your speed limit will be governed by your sensors. You need to be able to avoid the stray pebble in space. So you need to have sensors good enough to spot the threat with enough reaction time to get out of the way. This creates a danger cone that stretches forward as you accelerate. Assuming a meager 10 seconds of reaction time, that means being able to spot a very cold pebble at a thousand kilometers.