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Unmanned Spaceflight.com _ Titan _ TiME
Posted by: rlorenz May 5 2011, 08:48 PM
Ahoy mateys!
NASA announces Discovery mission selection for Phase A.
Titan Mare Explorer (TiME) is among them. Har!
Posted by: centsworth_II May 5 2011, 09:01 PM
Long may this thread live! To 2023 and beyond!!!
Posted by: Juramike May 5 2011, 09:09 PM
Whatever floats your boat! 
Congratulations! That is terrific news!
Posted by: ngunn May 5 2011, 09:20 PM
And a hearty cheer from me. 
I worked at sea for 17 years and nothing in solar system exploration excites me more than the prospect of sailing an other-worldly sea with the prospect of a huge science payoff.
Posted by: Drkskywxlt May 5 2011, 11:57 PM
Congratulations, Ralph, and also to your team!
Posted by: nprev May 6 2011, 12:00 AM
Wow, Ralph, MAJOR congrats!!! This promises to be one of the most exciting missions ever!!!
Posted by: titanicrivers May 6 2011, 12:25 AM
Excellent! Something to really look forward to.
Read the NASA press release here: http://www.nasa.gov/home/hqnews/2011/may/HQ_11-132_Future_Plantary.html
Posted by: punkboi May 6 2011, 02:11 AM
I hope TiME gets chosen in 2016. Outer Planet mission > Inner Planet mission
Posted by: SFJCody May 6 2011, 02:27 AM
I also prefer TiME to the other candidates. METNET can do some Martian geophysical studies and Rosetta/Philae can investigate a comet nucleus. But when's the next chance we'll get to see Titan up close other than this?
Edit: Oops, I forgot METNET was 100% meteorological! For some reason I thought it had a few geophysical instruments as well.
Posted by: stevesliva May 6 2011, 03:47 AM
Depends on how old you are.
Posted by: eoincampbell May 6 2011, 05:00 AM
I'm on TiME's side, Ligeia Mare, here we come, don't forget your wellies
Targeted landing on moon so far... awesome undertaking... really hope she goes
Posted by: antipode May 6 2011, 07:12 AM
I like all the selected missions, but TiME seems special in so many ways. The science, given the budget, seems compelling, but the public outreach!
I know the bandwidth will be low, but there is at least a simple imager on the mission isnt there? (yes, I know, all that may be nothing but a flat horizon all round and a dim cloudy sky, but to drift into view of a coastline before she gives out...(and she must be a she!)!
Actually has there been any work done on the possible entry ellipse and targeting accuracy yet? Is the desired target deep water....hydrocarbon...whatever....or a more littoral location?
Getting ahead of myself here...Congratulations Ralph and crew!
P
Posted by: machi May 6 2011, 10:03 AM
Congratulations Ralph and whole TiME team.
It's right time for TiME!
Posted by: Juramike May 6 2011, 01:37 PM
The real beauty of TiMe is that it's instrument package and environment would be perfectly scientifically complementary (synergistic with) all the other currently proposed Titan missions (baloon, JET, AVIATR airplane, future orbiter, etc.)
So if TiME is selected, it shouldn't hurt the chances of other proposed Titan missions from a purely scientific viewpoint.
Posted by: tfisher May 7 2011, 03:20 PM
I agree: of the three announced candidate missions, TiME really excites the imagination. I expect the images we get back would be pretty underwhelming : I picture something like the myopic postage stamps from the Huygens landing, except with the only visible scenery being a few ripples on a calm lake surface. But the idea of going to such a distant, alien location, and exploring in a way that has never been done before... That is exciting. This mission is about Exploration in the truest sense. I grew up thinking about space from the Star Trek perspective: "to explore strange new worlds, to seek out new life and new civilizations, to boldly go where no man has gone before." That is exactly what the TiME mission sounds like to me Well, minus the new civilizations, and probably [thought not quite certainly!] minus the new life forms. But certainly exploration of a strange new world. Contrast to the other mission proposals, which are more mundane planetary science. That is science with a small 's' : filling in details, trying to add a little bit onto the big pile of knowledge. Still interesting stuff, but not nearly so inspirational.
Posted by: centsworth_II May 7 2011, 06:19 PM
Posted by: tfisher May 7 2011, 07:39 PM
Does anyone know what liquid methane/ethane is like at Titan surface temperatures? Is the picture we should have in mind like rubbing alcohol, or gasoline, or motor oil? Maple syrup? Molasses?
Posted by: Juramike May 7 2011, 07:44 PM
Gasoline. Not as viscous as water, even at those temperatures. And definitely not as "clingy" as water on glass. Any splashes of liquid on the lenses should creep right off. Not sure about any residual materials, however. But that's one of the reasons TiME is such an exciting mission: just what other things are in those lakes, anyway?
Posted by: djellison May 7 2011, 08:14 PM
Moreover - TiME will be quite a warm thing - so heat will drive off and evaporate any splashes - residual residue isn't out of the question. The camera should be fairly high above the surface anyway, so it unlikely to get a splashing - especially given how smooth we know the lakes to be. Something over 500 watts of heat are involved in the 130 watts of electricity generated by the ASRG
Posted by: nprev May 7 2011, 08:39 PM
When exactly can we expect the final mission selection? The press release just says that there will be another review next year, no month given.
Posted by: ngunn May 7 2011, 09:03 PM
I was under the impression that it would aim to splash down a long way from land, probably too far for the shoreline to be visible during descent. Also I seem to remember it being said that it would all happen in darkness or at most twilight. Am I misremembering? Of course any image at all would be nice but I'd still back the mission even if there were no images, just great chemistry.
Posted by: centsworth_II May 7 2011, 09:16 PM
"Earth & the Sun are above the horizon for the 3 month mission lifetime, during which TiME collects and transmits data on the lake and atmosphere." http://www.spacepolicyonline.com/pages/images/stories/PSDS%20Sat1%20Stofan-TIME.pdf
Of course even at noon it's twilight on Titan, especially at the pole, I imagine. But I expect the imaging system should be designed to get good pictures throughout the entire mission.
As far as distance from the shore, the Huygens panoramas cover quite a distance. I don't know how much better the Time descent images may be or how high the probe may be and still capture shots of the shoreline.
Posted by: nprev May 7 2011, 10:06 PM
Thanks for those slides, Cents.
I'd actually call this mission a validation of the ASRG in three environments: space, alien atmosphere, and cryo hydrocarbon fluid exposure. Apparently, the ASRG provides enough power for DTE, which is a wow. Considering the fact that there's a Jupiter flyby in the trajectory, what are the odds of a teeny little ridealong cam, perhaps provided by another program...? 
(Disclaimer: If such a cam would add too much complexity to systems integration, then fuggedaboudit. Prime mission is too exciting & important to screw around with.)
Posted by: rlorenz May 8 2011, 12:13 AM
Actually, Mike, can be a little more viscous than water if it is ethane-rich.
Maybe even double the viscosity of water if Cordier's model composition
with several per cent propane and butane dissolved in is anywhere close.
see http://www.lpl.arizona.edu/~rlorenz/viscositywaves.pdf
Posted by: DFinfrock May 8 2011, 12:33 AM
Thanks seconded Centsworth!
I had no idea the destination lake on Titan was bigger than Lake Superior on Earth. What a mission.
Posted by: tedstryk May 8 2011, 01:35 AM
Time seems like quite a timely proposal. Congratulations!
Posted by: Juramike May 8 2011, 01:40 AM
Wow! The estimated viscosity of ethane compared to methane is completely counterintuitive. I wonder what the reason is? I'da thought that it was only intermolecular interactions via dispersion forces, and that one saturated C-H electron cloud would look like another. Off the top of my head, at those low temperatures I'd also guess that the two CH3 groups would be gauche to each other (hindered rotation), negating any hyperconjugation and thus increased polarization of the molecular orbitals.
(Note that N2 is not viscous - likely due to intermolecular lone pair repulsion).
Is it a size thing?
Posted by: djellison May 8 2011, 06:47 AM
Get out.
Posted by: SFJCody May 8 2011, 06:58 AM
TiME should be an aerobot rather than a boat. After all, TiME flies!
I could go on, I've got a million of these...
Posted by: nprev May 8 2011, 09:44 AM
I see that the UMSF bad pun tradition is alive & well. 
I suggest that if the secondary target is selected, TiME should be renamed "Nautical Exploration With Sonar/Wideband Evaluation [of] Exochemistry [at] Kraken".
I'll get my hat.
Posted by: jasedm May 8 2011, 10:33 AM
Just what I was going to say Mike......
Very exciting news about the proposal.
Re: pictures of the lake surface, artists renderings I've seen show what looks like a light source - enough perhaps with the available power to be able to get some some good images within a metre or two of the craft?
Posted by: machi May 8 2011, 01:23 PM
It looks (from scheme), that two imaging instruments are planned. One is down-looking (descent imager?) and on side-looking (panoramic camera?).
I would like to ask two questions. It's possible use descent camera to look at the bottom of the mare (if it's not too deep, liquid is transparent and probe has source of light) and I don't fully understand why is Ligeia mare primary target. It looks, that Kraken mare (secondary target) is better suited from communication point of view and is more suitable for possible mission extension.
Posted by: centsworth_II May 8 2011, 01:54 PM
Unfortunately it does look a bit iffy for getting good descent images of the shoreline. Just for fun, I superimposed http://www.nasa.gov/mission_pages/cassini/multimedia/pia07229.html over a http://commons.wikimedia.org/wiki/File:Titan_sea_map_without_grid.png. Haze would probably prevent good imaging outside of the green octagon, which barely touches the shore. The really good wide Huygens panorama was within the magenta circle, and the great landing area panorama would just cover the black X. I'm hoping for some improvements over the Huygens "camera". Maybe a telescopic lens?
The probe being blown to shore during the course of the mission doesn't look too good either. The probe could easily land 100 km from the shore and even a "perfect" wind, blowing constantly in one direction toward the nearest shoreline would need to blow the probe over a kilometer a day for three months. Not a likely scenario.
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Posted by: ugordan May 8 2011, 02:20 PM
You don't want a telescopic lens. It's not the angular resolution that's the problem, it's the haze extinction. You want a really good S/N ratio to combat the reduction in contrast when looking through an optically thick layer of haze. Huygens DISR was already pretty good in this respect. IIRC it returned 10 bit data to Earth, square-root-encoded from 14 bit A/D output. 10 bit data is still pretty much standard for spacecraft today.
Where there could be some improvement over Huygens is in selecting a narrow spectral window like ISS CB3 instead of a broader range Huygens used. This does come at a price though - much longer exposures needed and if your spacecraft is rocking really hard on the way down this virtually guarantees image smear.
Posted by: rlorenz May 8 2011, 03:00 PM
I'd love to enter the discussion, but the Step 1 selection just means this is now a much more
cut-throat competition, and many details of the mission will have to remain proprietary for now.
There are very smart people on the team (a look at author lists of abstracts will clue you in)
who spent a lot of time thinking how best to do imaging, and there are very good reasons
for choosing Ligeia, etc.
It is my intent to make as many details public as is feasible, to engage the scientific community
and the public at large to the greatest extent, but the competitive process will restrict that
for the time being.
Hopefully one day I'll get to write the full story in a book - the followup to Titan Unveiled. I'm thinking
a good title might be 'A Brief History of TiME'......
Posted by: brellis May 8 2011, 03:25 PM
Thanks for the laugh!
Posted by: Greg Hullender May 8 2011, 05:10 PM
Bravo!
I certainly hope to see this one fly.
--Greg :-)
Posted by: centsworth_II May 8 2011, 05:33 PM
What a problem! Designing a descent imaging system while taking volatile weather into account!
Posted by: ugordan May 8 2011, 05:53 PM
I was under the impression the haze doesn't "end" below a certain altitude, it just becomes transparent enough. It's not that thick per km to start with (not what you'd think of fog on Earth). Loking a hundred km into the distance horizontally likely wouldn't be any different than looking vertically. A narrow-angle imager would also be much more sensitive to atmospheric buffeting.
Posted by: eoincampbell May 8 2011, 06:57 PM
And hopefully we'll all get to read it!
Very best of luck to you and your esteemed colleagues, rlorenz, on this amazing adventure !
Posted by: nprev May 8 2011, 09:13 PM
Ralph, although I'm sure it's proprietary right now, I'll be fascinated to see the EDL methodology.
Posted by: ElkGroveDan May 8 2011, 09:34 PM
All in due...... well, you know.
Posted by: nprev May 8 2011, 09:55 PM
<groan>...walked right into that one!
Posted by: Explorer1 May 8 2011, 11:39 PM
With luck, there should be a naming contest or we'll have a full decade of puns to look forward too.
Or we can just avoid making clever acronyms (like MESSENGER) in the first place and give the mission a normal name from the start, like New Horizons.
Alan Stern put it best way back when:
http://pluto.jhuapl.edu/overview/piPerspective.php?page=piPerspective_05_2005_1
Posted by: nprev May 9 2011, 12:31 AM
Not a bad point, Explorer, and I think that NH was very well-named indeed.
Too bad that so many of the maritime pioneer names have been taken; TiME, of all missions to date, deserves a nautical name. Frankly, though, I don't care if we call it the "Benthic Explorer: Nautical Depth, Environmental Reconnaissance" or "Nautical Probe: Revealing Ethane Vastness" ; I just want it to fly, very, very badly.
(Okay...so maybe I would slightly favor the latter acronym...)
Posted by: DFinfrock May 9 2011, 01:18 AM
We've honored past astronomers with Galileo, Cassini and Huygens. So why not honor a mariner like Captain James Cook, Roald Amundsen, or James Clark Ross. It seems that an explorer of the Arctic or Antarctic oceans would be a good choice for a robotic explorer of the frigid lakes of Titan. Or maybe even a ship's name? Perhaps the Fram, or even the Titan Challenger, to honor that historic 19th century oceanographic voyage.
Posted by: jasedm May 9 2011, 04:35 PM
I vote for Shackleton's ship 'Endurance' :
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Posted by: dmg May 10 2011, 12:44 PM
Despite the honor of Shackleton & men and their long struggle, not sure if that is the best name for a probe with a (sadly) limited mission life
Posted by: MahFL May 10 2011, 01:46 PM
How about "Armada" from "The Spanish Armada" , they did not last very long.....
Posted by: nprev May 10 2011, 10:21 PM
I like "Admunsen"; seems like a very apropos honor for him, and for the Titanian environment. Alternatively, if naming TiME after a polar sailing ship that lasted a limited time or made a limited voyage is the selected paradigm, what was/were the names of his ship(s)?
Posted by: djellison May 10 2011, 11:13 PM
Amundsen and Scott were names for the DS2 microprobes, so that's out.
Posted by: nprev May 10 2011, 11:20 PM
Argh...right, right...bummer!
Hmm. Wonder if there are any historical Aleut, Inupaq (sp?), or other "Eskimo" sailors? Should be; they were seafaring people, albeit limited in sortie length by environmental constraints. A name from that tradition would also be quite appropriate (esp. since the mission would be targeted for the north polar area of Titan).
Posted by: stevesliva May 10 2011, 11:33 PM
Call it the Cuyahoga. Volatile organics and all that.
Posted by: tedstryk May 10 2011, 11:36 PM
Do those count as real spacecraft?
Posted by: Drkskywxlt May 10 2011, 11:40 PM
How about the Fram?
http://en.wikipedia.org/wiki/Fram
Sailed further north and south than any other wooden ship.
Posted by: djellison May 10 2011, 11:42 PM
They certainly weren't fake.
Posted by: elakdawalla May 11 2011, 12:38 AM
Obviously NASA can set the rules any way it wants. But for the Mars Exploration Rover naming contest, any name ever used for any spacecraft in the past was out, which eliminated what many considered the most obvious choices for their names: Lewis and Clark. (2005 was the bicentennial of the start of their expedition, so it would have been very appropriate.)
Posted by: Bjorn Jonsson May 11 2011, 01:02 AM
The names of the Vikings that discovered Greenland and North America about 1000 years ago are names that for obvious reasons look like obvious choices to me (although which spelling of their names to use (English, Icelandic, the spelling used 1000 years ago or even Norwegian) isn't totally obvious).
That said, I hope TiME gets selected. It looks like an extremely interesting mission, especially when keeping in mind that there's no flagship mission to Saturn in sight for the next 1-2 decades or more. I'm pleasantly surprised at how interesting/ambitious all three proposals look considering that these are 'only' Discovery missions. Chopper is my second choice (there has been a lot of Mars missions over the past 15 years).
Posted by: djellison May 11 2011, 01:53 AM
Hey - we could call it TiME.
Posted by: nprev May 11 2011, 01:57 AM
To be sure. The clock is indeed ticking; to answer my own question, the final selection apparently happens in June 2012.
Posted by: polaris May 11 2011, 02:08 PM
I agree ! And I'd add soma other names to the list : Jean-Baptiste Charcot or his ship "Pourquoi-pas ?" ("why not ?" in english), or Jules Dumont d'Urville or his ship "L'Astrolabe"...
Posted by: Stu May 11 2011, 02:12 PM
It would never happen in a gazillion years, I'm sure, but I'd love it to be called "Nautilus", after Captain Nemo's famous craft that battled the Kraken in Jules Verne's book...
Posted by: tedstryk May 11 2011, 05:17 PM
Perhaps Champlain would be a good name, since he named/explored Lake Ontario.
Posted by: tedstryk May 11 2011, 07:09 PM
They could, but they won't.
Posted by: Astrophil May 12 2011, 07:58 AM
Not an explorer, but – Coleridge: “We were the first that ever burst / Into that silent sea”.
[EDIT for misquotation first time]
Posted by: Phil Stooke May 12 2011, 11:37 AM
"Parachute Landing On Puddle"
PLOP!
Or maybe...
"Small Polar Landing And Sailing Heroically"
SPLASH!
Phil
(had to bring it down to my level eventually)
Posted by: centsworth_II May 12 2011, 12:31 PM
Titanic?
Or -- since Time is a raft -- Kon-Tiki. (It's the only famous raft name I could think of.)
Posted by: titanicrivers May 12 2011, 12:49 PM
How about the good ship ARGO. (I don't have to tell you what the team members will be called)
Posted by: remcook May 12 2011, 02:21 PM
Huckleberry? Not the name of a raft itself...
But TiME allows for many more puns
Posted by: machi May 12 2011, 02:30 PM
Personally I like Fram and Endurance. These names looks really appropriate for such cold place.
Posted by: ElkGroveDan May 12 2011, 02:30 PM
A ship out on one of the Great Lakes in cold nasty weather... I've got it! How about the Edmund Fitzgerald?
Posted by: titanicrivers May 12 2011, 02:54 PM
Hmmm .... that one sank and was not heard from again ... sad to say.
Posted by: DFinfrock May 13 2011, 01:02 AM
So did the Endurance. But thanks to Shackleton's heroics, everyone on board survived.
I am still amazed every time I think of that feat. His ship crushed by the ice... no radio or communication of any kind with the outside world. Yet he didn't lose a single sailor. If you have never read that story, do yourself a favor and do it now.
For that matter, in his earlier expedition attempting to reach the South Pole, he turned back around 100 miles from his goal, based on consumption of their supplies, and the estimated time to return to their base. Scott later made it to the South Pole, and received posthumous honors for his bravery. (Everyone in the party died on the way back). But I would have preferred Shackelton as my leader.
David
Posted by: DFinfrock May 13 2011, 01:10 AM
Stu, We need to keep that name in reserve... for the first submersible explorer of Europa's oceans!
David
Posted by: AndyG May 13 2011, 10:25 AM
Though there's the sad story of http://www.purr-n-fur.org.uk/famous/chippy.html, ship's cat.
Andy
Posted by: MahFL May 13 2011, 12:55 PM
Cat's are a law unto themselves, ours called "Chase" is no exception.
Posted by: djellison May 13 2011, 01:39 PM
Heck, call it James Caird.
Posted by: Paolo May 15 2011, 08:44 AM
a technical question: any idea of the data rate of TiME and of the amount of data expected from the primary mission?
I get the impression that there will not be enough bandwidth for serious imaging
Posted by: Phil Stooke May 15 2011, 03:49 PM
My concern too - coupled with the brief mission after a long silent cruise (no flyby science at Jupiter) - makes me prefer the other options.
Phil
Posted by: nprev May 15 2011, 05:20 PM
On the other hand, it's gonna have gobs of power, WAY more than, for example, the MERs & other solar-powered spacecraft. I imagine that TiME might run dual-transmitter during the primary mission as is planned for NH, which should provide adequate bandwidth for image & data return.
Posted by: mchan May 15 2011, 09:11 PM
Just because TiME will use an ASRG (or two) does not necessarily mean more power than a solar-powered soacecraft. It is independent of distance from Sun. But then it will also be at Saturn distance, not quite as far as NH will be, but still much farther out than MER. As with solar flux, comm power goes down by inverse square of distance, and TiME will not have a big high gain antenna. To a first order, my guess is TiME comm bandwidth will be an order of magnitude less than that of Cassini.
Since it will be out of line of sight to Earth for at least half of Titan's orbit, TiME may use rechargeable batteries to increase peak power during the times it can transmit to Earth similar to MSL for driving.
Posted by: Bjorn Jonsson May 15 2011, 10:39 PM
An extremely crude back-of-the-envelope calculation: Assuming an antenna/transmitter comparable to Cassini's but 10 times smaller you get approximately 1000 bps. That's over 10 times the typical Galileo rate on a spacecraft with fewer instruments where everything is designed with that data rate in mind, unlike the case with Galileo. Of course, lacking more information, this is all highly uncertain but it seems to me the data rate must lie somewhere between 100 and 10,000 bps and even the lower number gives you a great mission (just look at Galileo).
Posted by: ngunn May 15 2011, 10:49 PM
I'm on board. There's no fatal flaw with the mission. Bring it on and reveal the chemistry.
Posted by: Bjorn Jonsson May 15 2011, 11:07 PM
Thinking more about this, the Galileo LGA might be a better analogy than Cassini's HGA since it would probably be difficult to aim a narrowly focused signal to Earth. But even that should give you a respectable data rate for a mission like this.
Posted by: stevesliva May 15 2011, 11:39 PM
And of course, as long as the descent imaging and initial panos can be stored, some have said the view might not change all that much.
Might be cool to watch for weather, though. Clouds and fogbanks. But that can be done with thumbnails and highly compressed images to see whether there's weather.
Posted by: machi May 15 2011, 11:53 PM
"any idea of the data rate of TiME and of the amount of data expected from the primary mission."
In very similar Titan Lake Probe study was DTE data rate 400 Mb/32 days. This is around 500 bits/s, relatively nice data rate from such great distance.
For 3-months primary mission it's approx. 1.1 Gb. For example, this is equivalent of 400 1 Mpix images with lossless compression or around 2000 images with lossy compression.
Posted by: JGodbaz May 16 2011, 01:08 PM
Except that the vast majority of the data will probably be GCMS results, which are a little less photogenic, albeit very scientifically valuable.
Posted by: centsworth_II May 16 2011, 02:16 PM
Maybe out of sight less than half Titan's orbit. How long would Titan actually be behind Saturn, or close enough to prevent communication?
Posted by: tanjent May 16 2011, 03:08 PM
Good point. Roughly speaking the Earth should be visible for about as long as the sun; from the polar regions basically 'round the clock until the next equinox. It will be getting pretty close to the horizon, though.
Posted by: ElkGroveDan May 16 2011, 03:10 PM
I suppose engineering specifics are way down the road on this, but I can't help but wonder what kind of materials and design they are going to use for the "hull" of this vessel. It's been a few decades since I studied materials science, but intuitively it would seem that it's going to be difficult to isolate the heat from whatever warm-electronics-box will be buried in the craft's interior, not to mention protruding instrumentation. Compared to the temperatures internal to most spacecraft, it wouldn't take much to nudge the outer structure a couple of degrees above the boiling point of the liquid it will be floating in (-250 -260 F or whatever the exact figure is).
The other issue that comes to mind is the mechanical characteristics of whatever outer cryo-materials will be used. They are going to need structural members that will survive launch vibration conditions and still retain or resist changing ductility and brittle conditions over such a wide temperature range during and post-EDL. It's going to be a fascinating process and I can't wait to read about the engineering challenges and solutions.
Posted by: centsworth_II May 16 2011, 04:12 PM
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Posted by: Bjorn Jonsson May 16 2011, 04:41 PM
This only happens near the time of the Saturnian equinox as seen from Earth.
Posted by: centsworth_II May 16 2011, 04:42 PM
Posted by: Bjorn Jonsson May 16 2011, 05:02 PM
No, it won't happen (unless you get a *very* long extended mission).
Posted by: helvick May 16 2011, 05:21 PM
Dan - I wouldn't have thought that sort of temperature isolation would be an insurmountable technical challenge provided you don't want to put any active components on the outside of the hull. The JWST has active components sitting in the cryosection at around 35K connected to the ISIM (the Integrated Science Instrument Module) that operates at ambient (300K) via a 4m cable that requires some serious engineering so it is possible but I suspect that the mass of the multi-stage cooling system required to allow that would not be possible on TiME.
Posted by: centsworth_II May 16 2011, 08:46 PM
Posted by: nprev May 17 2011, 12:34 AM
One thing to consider is that TiME will require VERY long periods of DSN use since the bitrate is going to be relatively low. That may be as much of a limiting factor as anything else.
Posted by: rlorenz May 17 2011, 05:35 AM
I'm glad to see that you lot are thinking about all this - fun, isnt't it?
Obviously I'm not going to go into specifics but it is possible to address some of the questions that have
come up in very general terms.
Materials/temperatures - guys, come on. Huygens operated in this environment until its batteries ran
out. Launch vehicles - to say nothing of the liquified natural gas industry - deal with cryogenic fluids
all the time. Of course heat leaks and insulation need to be designed appropriately, and material
properties at the relevant environment must be considered, as they do on Mars and Venus or in vacuo.
Communications - some cogent discussion on the thread. This has been thought about a lot for Titan
balloons too. I'll remind readers that many cruise ships, and drones for that matter, use gimballed
antennas for satellite communications. Again, not trivial, but a familiar and soluble problem.
As for data - have a look at the Huygens or Pathfinder or any other mission's balance of data volume
between imaging, composition, meteorology etc. On any mission this balance gets struck somehow (and
indeed it can often be tuned during the mission)
Posted by: ElkGroveDan May 17 2011, 06:07 AM
out. Launch vehicles - to say nothing of the liquified natural gas industry - deal with cryogenic fluids
all the time.
Thanks for responding Ralph. My actual concern was not so much the low temperatures affecting the TiME craft as the other way around. If it drops down in that hydrocarbon sea and then sets it boiling and steaming that would seriously affect instrumentation's ability to collect data would it not? If nothing else images would be difficult. With respect to terrestrial cryogenic industrial uses, to the best of my knowledge none of that equipment is required to go through launch vibration tests at STP and then transition to high loads and stresses in cryogenic environs. My armchair recollections are that materials which are strong and ductile at one end become fragile and brittle at the other end and vs. vs. Certainly the temperatures we are dealing with are substantially lower than any of the Mars craft were designed for, and then finally the whole notion of the vehicle in contact with an ocean of liquid adds a heat capacity component to the materials calculations that is barely a factor in the gaseous 0.01 atm on Mars.
I'm certainly not questioning your knowledge or understanding of the conditions (I read your book), just outlining my line of thinking that caused me to pose (perhaps in-artfully) the previous question.
Posted by: rlorenz May 19 2011, 03:54 AM
.....
I'm certainly not questioning your knowledge or understanding of the conditions (I read your book), just outlining my line of thinking that caused me to pose (perhaps in-artfully) the previous question.
Dan
I realize your questions are well-intentioned and motivated by your excitement about this mission (an excitement
that is widely shared). The fact is that any measurement perturbs its subject (qv quantum theory)
and this applies to a warm lander on Titan, a warm lander on a comet, or a geophysical lander on Mars that couples
wind energy into the ground.
It is also a fact that a Phase A study is just that, a study. Only one of the three missions under study is likely to fly (and NASA
reserves the right not to fly any of them!). Remember too that USMF is read by many in the planetary science community.
Thus people who may be reviewing study reports in the future and deciding what flies could be reading your question.
Developing a full answer that satisfactorily addresses your question (or any other from someone else) may require more text than
most people want to read, more of my spare time than I can afford, or may require details that are proprietary to
my employer or one or more of the industrial/agency/academic partners in the project. So a complete answer cannot
be given, and an incomplete answer may be seen as indicating a weakness that may not exist or may be otherwise
taken out of context.
Thus by asking a question of a mission in competition in a public forum you actually may make
the mission less likely to happen. There does not exist at present a 'people's court' wherein missions under competition
can be probed by the public in an equable manner, appealing as such a notion may be (and it may not appeal for example
to industry). And probing at concepts under study in an ad-hoc manner, wherein all concepts under competition are not probed
equally, could be prejudicial to the decision-making process. So I ask your understanding that I cannot discuss such details.
All I can say is the challenges of doing science in an exotic environment are recognized by a team that has successfully
addressed such challenges before. The detailed plans for doing so will be evaluated in NASA's formal review process.
And let me take this opportunity to remind readers that (roughly) for every scientist out there doing cool stuff like studying
pictures on Mars, or analyzing bits of asteroids, there's another (nameless) scientist who doesnt get their name on papers, or appear
on TV, but who had to sit on a tedious peer review panel for a week in some dreary hotel, and read hundreds of pages of dense proposal
material to help judge which 1 of 5 scientists should be picked to work on the team, or which mission should fly, when
actually the top 3 out of the 5 would all be superb. A painful decision, and an onerous duty, but one that is rarely
recognized outside the field.
Posted by: nprev May 19 2011, 04:27 AM
One overarching thought: Somebody, sometime, has to be the one to do any given thing first for any given situation.
TiME would be one of the most memorable of those in my lifetime.
I suspect that the general public will feel much the same.
(Damn right this is a shameless plug!!!)
Posted by: ngunn May 19 2011, 07:30 AM
the mission less likely to happen. There does not exist at present a 'people's court' wherein missions under competition
can be probed by the public in an equable manner, appealing as such a notion may be
Ralph, as ever your insights are most welcome and highly prized here. There is no 'people's court', and yet inevitably there is bound to be some kind of 'people's court in exile', articulated in small part on this forum. You say that posing questions here may have a damaging effect. Let's hope enthusiastic support can work the other way. I think it's pretty clear you already have the majority of the jury.
Posted by: ElkGroveDan May 19 2011, 02:14 PM
Thanks Ralph. Really just curiosity on my part. I am fascinated by physical challenges and cutting-edge solutions. I am grateful for your willingness to share with us when you can. Best of luck with this.
Posted by: toddbronco2 Jun 2 2011, 09:55 PM
I think it's "time" for TiME to graduate to its own Saturn thread instead of being forever buried in the Cassini Huygens sub-threads.
Posted by: rlorenz Jun 27 2012, 04:53 PM
Hmm, perhaps. It even gets a mention on xkcd today......
http://xkcd.com/1074/
Posted by: Paolo Jun 27 2012, 05:45 PM
wasn't the next Discovery mission selection to be announced this month?
Posted by: rlorenz Jun 27 2012, 10:39 PM
NASA presentations have said 'Mid-July'
http://www.lpi.usra.edu/meetings/lpsc2012/events/highlighted/Green_LPSC.pdf
Posted by: Roby72 Jul 15 2012, 11:00 PM
"Exploring Titan by boat":
http://vimeo.com/44046816
I hope that TiME wins the decision of "Discovery 2012" !
Rob
Posted by: titanicrivers Jul 16 2012, 04:21 AM
Interesting video and presentation by Dr. Ellen Stofan. Not sure of the exact date of this talk but its been posted since the 2nd week of June. Her review of Titan's geology and the TIME mission is beautifully done.
An interesting revelation occurs at the 18:00 minute mark when she hints strongly that another volcano has been discovered in the radar swath of the Titan flyby 'last week'. If I have my dates correct that would be the T84 flyby SAR taken on June 7th! http://www.ciclops.org/view/7216/Rev167
Not exactly sure where along the T84 groundtrack http://www.unmannedspaceflight.com/index.php?act=attach&type=post&id=26929 the possible volcano is but can't wait to see that SAR.
Posted by: Ondaweb Aug 21 2012, 01:05 AM
I'm very distressed to learn today that a mars lander/seismograph was chosen rather than Time. Much as I like Mars and would like info on the interior, TiME seemed to have a much more potentially interesting payoff.
Posted by: nprev Aug 21 2012, 01:06 AM
It is what it is; gotta press on. Perhaps it will win the next Discovery round.
Posted by: Paolo Aug 21 2012, 06:31 AM
just wondering (sorry if this has been already asked or if it's a silly question): since a northern mare landing seems to be ruled out until the 2040s, would a southern landing in Ontario work?
Posted by: Webscientist Aug 21 2012, 08:32 AM
To me, a sad day for science and exploration!
Another mission to the martian desert. We already have three rovers on Mars.
They forget Venus, Europa, Titan, Enceladus and Triton!
Yet Titan may be the right place to better understand the chemistry of carbon and the mechanisms that may lead to the emergence of a carbon-based lifeform.
Titan has lakes, seas and rivers but people focus their attention on the martian desert and most people don't know Titan.
Really surprinsing!
Posted by: antipode Aug 21 2012, 10:27 AM
I suspect no-one's forgotten any of them.
Where's the money?
P
Posted by: MahFL Aug 21 2012, 10:45 AM
Er one of the three rovers on Mars is dead, so there are two operating.
Posted by: ugordan Aug 21 2012, 11:10 AM
And that totally invalidates his point....
Posted by: nprev Aug 21 2012, 11:53 AM
Everybody, once again a reminder: Review the rules (esp. 1.2 and 1.7) & post accordingly.
Posted by: rlorenz Aug 21 2012, 02:30 PM
One never says never in this business, but Ontario is (a) known to be shallow and (
is much smaller than Ligeia, and quite likely smaller than the landing ellipse for a passive descent.
Posted by: ceramicfundamentalist Aug 22 2012, 01:30 AM
While the time-sensitivity of TiME was all the more reason to select it now, it may have also contributed to the budgetary and technical risk associated with the mission. I can imagine the project falling behind schedule, then having to (potentially massively) overspend to catch up. don't get me wrong, I was rooting for TiME because it is awesome, but there's almost no debating that Insight is the better Discovery mission.
Posted by: Webscientist Aug 22 2012, 08:19 PM
is much smaller than Ligeia, and quite likely smaller than the landing ellipse for a passive descent.One may expect that the level of Ontario Lacus could rise as the Winter season approaches in the southern hemisphere (Winter Solstice in 2016 if I'm correct).
Mezzoramia may become the Kraken Mare of the southern hemisphere (as Volcanopele had already suggested a few years ago).
The south polar vortex recently observed is probably the sign of a change.
Let's be patient and let's observe!
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