...Interesting thread here. Long ago Trafton and I calculated the heat rise in Charon
owing to tidal despinning: it's fairly negligible. McKinnon later got a similar result with
a better model. The reason Charon is devoid of volatiles on its surface is most likely due
to its lower gravity, which promotes rapid escape of volatiles that sublime into the
atmosphere. As a result, volatiles on Charon's surface suffer the fate of quickly
escaping to space, leaving behind a lag deposit of involatile mateirals (e.g., H2O,
low vapor pressure organics, dirt) that eventually grows deep enough to choke
choke off sublimation, isolating the surface from the interior. Charon might well have
interior volatiles that only reach the surface occasionaly, e.g., when a big impactor
dredges them up.

As you say, we'll look for evidence of volatile loss history when
NH reconnoiters the system.

...46 days to launch, and counting.

-Alan

I wanna see frozen geysers and tar pits and volcanoes and mud pots on Charon!



Oh well, whatever . . . .

Would there be any idea as to possible primodial rotation rates for Pluto and or Charon (assuming they formed with the rest of the solar system and not as a result of an 'Orpheus style' impact) ?

Can this info help tease out a possible distance that Charon may have receded from Pluto during the spin down ?

Like if Pluto and Charon both fomed with 10 to 15 hour rotation periods, can the angular momentum of Charon be 'run backwards' mathematically to derive the seperation distance at that early stage?

I'm thinking if we can get an idea of how far Charon receded from Pluto, we might further get an idea of the 2 new satellites original orbirts before they were snagged in their respective resonances (if they are in fact determined to be in resonance with Charon).

Good ideas! Read Robin Canup's 2005 paper in Science on the origin of Pluto
and Charon via impact, or McKinnon's work in my chapter of the 1997 Pluto and
Charon U of A book. Charon probably formed near Pluto's Roche lobe,
migrating outward from there. We can trace their history back from that starting
point to the present, and the same for P1 and P2, assuming the giant impact.

And what if there were no giant impact? Then we are lost, for there is no
good competator that explains the mass ratio and angular momentum excess
of the binary.

-Alan

I admit to being just a little bit agnostic about the collisional origin of Charon.

{with no good reason either, I have even cited the collisional theory in regards to Charon favorably in some of my speculations on the Iapetan equatorial ridge structure}

If tidal heating of Charon doesn't provide enough BTUs for methane blow off, but persistent low gravity does, well we have an answer then.

If Charon accreted just outside Pluto's Roche lobe after a violent collision blasted material there, that might have evaporated some volatiles too, perhaps.

Once Charon formed, and 'cleared' out the reisdual debris, then it may have been quiescent ever since. Or perhaps it will be Miranda-ish, if it absorbed some 'chunkified' subsatellites that were disimilar density wise with the majority of the other 'sweepings'.

If Pluto has been substantially calm since then, too, perhaps some of the Iapetus speculations will cross pollinate back to Pluto/Charon.

Fortunately, we have a test case -- our dear new friend the 10th Planet, 2003 UB 313. Its moon is much smaller and much more distant than Charon -- only about 250 km diameter, and 40,000 km from the planet -- but 2003 UB 313 nevertheless is coated with methane frost in amounts similar to Pluto. This suggests that Dr. Stern is right: the biggest KBOs have surface methane frost simply because they're bigger and can hold onto it, whereas CH4 frost quickly sublimates away from the exposed surfaces of smaller KBOs (including Charon).

To bad 2003 UB 313 is not close to Pluto. I would have love to have seen it after the Pluto flyby.

I got my fingers crossed for another Wopper of a KBO.

Next year .....29 years after it's launch from Earth , Voyager-1 is about to become first spacecraft to go beyond 100 Astronomical Units!!!

Click to view attachment

Does anybody have an idea how fast will "New Horizons" travel once it passes Pluto?
What I mean is will it eventually become farthest man-made thing?
BTW graphic is from "www.heavens-above.com"...

It took Voyager 2 12 years from Earth to Neptune (granted, Voyager 1 is a bit faster than that), NH will travel to Pluto in less than 10 years so simple logic says: yes, eventually NH will supersede even Voyager 1. But that's quite a long way into the future, Voyagers got one heck of a head start...

Here is a starchart showing the current positions of the Pioneers and Voyagers if we could see them in the sky from Earth.

More details

Hm... Something looks very wrong with that map. Both Voyager 1 and 2, for example, seem to be too close to the ecliptic. I'm having a hard time reading the numbers which I assume are predictions for the given year.

Voyagers are waaay above/below the ecliptic now, that map could be an old one, I certainly wouldn't say it shows the current positions.

If you or someone could create a current skymap of where our first four interstellar probes are, that would be wonderful. Especially one that is continually updated. And perhaps even as seen from different perspectives in space.

On the satellite observing website www.Heavens-Above.com is a section "Spacecraft escaping the Solar System."

It shows live data of all of this, and includes what constellation they are in along with the Ra. and Dec. of where you can find them (not that any telescope is going to help!). There is no skymap.

Not hard to find:
http://space.jpl.nasa.gov/
From following screenshot, is clear that Voyager2 is a lot below ecliptic (consider grandangular FOV of 120deg):

I don't have the tools or data, but from the summary presentations, New Horizons will pass Pluto at a relative velocity of ~13.8 km/sec. It's nominal path will be close to radial from the sun, with some tangential motion from the Jupiter gravity assist fly-by. Pluto's velocity is about 6 km/sec, also mostly tangential to the sun, so this contributes to the relative velocity. Therefore, the velocity of New Horizons relative to the sun will be <13 km/sec. It is unlikely that it will match Voyager II's 17+ km/sec radial velocity, and so never surpass it in distance. (It is hard to beat four gravity assists for picking up speed. Pluto, on the other hand, will not make a significant change in the velocity or direction of New Horizons. I believe that it is too small.)

Anyone on the mission team should be able to find the actual radial velocity in a minute. Can someone volunteer real information rather than this guess?

The wheels are in motion....

Atlas 5 rolls to the pad for countdown rehearsal

Voyager II experienced a rather large deflection at Neptune (IIRC 40 degrees or so) but no gravitational assist as it had at Jupiter, Saturn and Uranus. The polar passage over Neptune to realize the Triton encounter did not 'boost' the craft speed relative to the sun. (I seem to recall a very slight decel, in fact)

Pluto's mass is indeed too small to deflect the trajectory much, but radio tracking of NH will help refine Pluto system mass estimates.

I hope the 2 new satellites are visible in the NH cameras from a long way out, perhaps optical tracking can help pin down their inclinations and eccentricities. Is it too much to hope their masses can be nailed down too?

Perhaps we will find one or both chaotically tumbling like Hyperion . . . .

A historic space mission nears launch

Next month NASA is scheduled to launch New Horizons, the first
spacecraft mission to Pluto. Alan Stern, principal investigator on
the mission, gives an overview of the mission and its importance to
scientists and to the country in general.

http://www.thespacereview.com/article/509/1

They'll certainly be visible. NH will exceed HST's resolution for months on the way in. For a long time, the new moons will be seen as single-pixel entities. Near closest approach, they would appear bigger, although competition for instrument pointing will be intense.

I don't see how either could have [significantly] chaotic rotation -- Hyperion gets yanked around by close approaches from Titan. There's no equivalent that either of these moons has to put up with. They will either be tidally locked or rotating regularly.

I once had an equation that predicted pretty well which solar system bodies have tidally locked rotation and which didn't. It would be interesting to apply it to these new moons; someone else will have to do that...

I admit to being quite interested in the odd tumbling of Hyperion and wanted some more examples for study. Hyperion being in a resonance with Titan, and the new Pluto moons apparently being in resonance with Charon, I was cautiously hoping for a 'toe in the door' for some more chaotically tumbling objects. I have thought that direct overhead sunlight exposure might explain the dark bottom craters of Hyperion, and another object or two in a similar state might help pin down some theories.

Tide lock predictions for the new moons would be useful for theoretical work, too.

If I may ask, did your equation generate times to tide lock for various bodies?

I have speculated that tide lock for Iapetus was very slow to occur, but I have no idea if thousand, millions or billions of years is the actual number.

Hello Everyone,

Really interesting to read the discussions you guys have had about New Horizons on the site.

Many of you may remember me as "the high school kid" who created the website to try and keep NASA on course with a mission to Pluto.

Since no real campaigning has been necessary for the mission since the 2 initial bouts after New Horizons has been selected, I've been in "hiding."

It's great to see New Horizons so close to launch. Luckily, I was able to spend 2 summers interning on the mission with Dr. Stern out in Colorado and with the E/PO Team down at Johns Hopkins. What a great opportunity and experience!

Just a few days ago I was down at KSC getting interviewed for a documentary they are doing on the Mission, titled "Passport to Pluto". It's going to air on the Discovery Science Channel and NASA TV, so stay tuned for the program it promises to be enjoyable.

http://passporttoknowledge.com/

I'd been to KSC before but it was great seeing the third stage delivered and the Spacecraft sitting and waiting for fueling. It was also great to see some of the people I'd worked with since my involvement with the Pluto mission again. The Atlas V is amazing! Being out at the pad it was really great to be there knowing this thing is finally going to happen thanks to the efforts of so many in supporting this mission through thick and thin!

Take care all and onward to Pluto!

Regards,
Ted A. Nichols II

They getting up New Horizons to put in upper stage.

Either that or they're preparing to put NH on that spin table for its "wet" spin balance testing, planned for tomorrow and Wednesday.

Oh, and this article should annoy you a bit (unless you agree with the guy):

http://www.news-journalonline.com/NewsJour...OPN45120405.htm

I'm sorry... I don't have the schedule of NH processing..

Nasty article. I really get cheesed off with people who deliberately distort data in this way and choose to ignore far more significant and genuine threats.

There are valid concerns related to plutonium but of all the possible things to do with the damn stuff, sticking it on a nice big fat rocket and sending it to the outer solar system where it can help do stuff that contributes in some way to the betterment of all mankind is probably the single smartest thing you can do with it.

I'm not against use of the nuclear energy and I think that the use of the nuclear energy currently in space activities incases perfectly in the use of RTGs, MMRTGs.
I can not see other form to acess deep space if not with RTGs.

Nuclear energy is a potential and we have to use it.

http://www.nuclearspace.com/

Just because the new moons seem to be in orbital resonance, of course, doesn't mean they are in rotational resonance. Pluto is in orbital resonance with Neptune, but this has no visible impact on Pluto's rotation.

My equation simply lumped a few "lock-causing" factors together and thus measured the tendency to lock. Whether or not a world would be locked would also depend upon the internal structure (unknowably variable), the initial angular momentum (unknowable). Basically, it produced large values for Io and tiny values for Pluto and values in the middle for, eg, Hyperion, Mercury, and Iapetus. But for all we know, felicitous impacts braked Iapetus to a halt before tides had a chance to step in. Alternatively, it might have started at a spin so fast that it almost flew apart. Because we can't know the initial rotation, we could never pinpoint how long it took Iapetus to brake.

Yeah.. it's seems other spin test..

Some more good news, the Atlas V successfully completed the countdown dress rehearsal. No problems reported.
http://www.spaceflightnow.com/atlas/av010/status.html

Note the frosting on the booster from the LOX.

Sorry, if I might've sounded like a smart aleck. It was unintentional



And here's the schedule as posted by another member:

Dec 6-7 "Wet" spin balance testing
Dec 9 Mating of NH and 3rd Stage
Dec 12 Encapsulation of NH stack inside fairing
Dec 16 Transport of stack to pad.

Jan 11 Launch scheduled for 2:11 PM EST

Striking machinists ask Boeing to delay NH launch.
Union says replacements not qualified for work.

http://www.al.com/business/huntsvilletimes...5230.xml&coll=1

Rakhir

Welcome to Unmanned Spaceflight, Ted Nichols!

I dont think it's an exageration to say that this mission quite probably wouldnt have happened without your website. I remember it well - and it doesnt seem that long ago really does it

Was it you who did the '01 lander website as well? Didnt quite save it then - but at least it flys in '07. Only Marie Curie left, and imho that should be put into a museum with a good perspex cover so you can get really close, but it cant get damaged

Doug

Unions, unions, unions...

Aerospace engineer Harrison Quigley led that fight. Here is a space.com article on the campaign. I wonder if he will drop by as well?

And I'd like to add my welcome to Ted as well. Not long now 'till they light the candle...

Nice little article on "Spacedaily" site...:
A Historic Space Mission To the Third Zone Nears Launch

I particularly like this part:

Fine article.

Interesting thing with those odds - people regularly win the lottery. But have we ever had a release of plutonium from a failed launching of a probe? I imagine if the effects were as far-reaching as that article says, everyone would have heard about it.

I liked a bit in Enterprise, Dr. Soong is commented on how people reject new ideas, and he spoke of nuclear power.
"So did splitting the atom [cause suffering], and yet the first ships to colonize the solar system were nuclear powered."
I feel that that is an accurate assumption. Maybe in a decade, NASA will restart the Prometheus project, and we'll finally see fission-reactor-powered probes on their way to other planets.

I support nuclear power in space, but I do oppose nuclear weapons in space, at least for purposes of attacking other people. Should a nuclear device prove useful in deflecting an asteroid, I will support that.

And speaking of NASA "rolling the dice" with people's lives, well heck, just the fact that there is not a lot of funding allocated toward finding near-Earth-objects indicates that the governments of the world are "rolling the dice" with the entire planet. Sure it's unlikely that something will hit us in the next hundred years. But something is going to hit the planet again at some point in time (sounds like a US terror alert, doesn't it?). I just think it would speak volumes about our capabilities if we were able to find and deflect an object that posed a threat to the existence of our species.


At any rate, here's to hoping that New Horizons' journey here proceeds on schedule.

I'd like to squash him with the size solar panel needed to operate at Pluto's distance ;-)

I'm ashamed of the News-Journal for publishing that fact-unchecked editorial.

There is, indeed, a vast difference between nuclear power systems and thermonuclear explosives. The former are used to generate electrical (or propulsive) power. The latter are simply designed to explode.

An explosive is not intrinsically a weapon. It's the old NRA ad slogan -- nuclear weapons don't kill people, people kill people. But if you build explosives, for whatever reason, someone will eventually at least *threaten* to use them as weapons.

I don't like the idea of deploying nuclear explosives in space for *any* reason, because until and unless they are used for some peaceful purpose (like deflecting an asteroid or blowing apart a comet to see what's inside), they are available for weapons use -- or at least, they are available to back up the threat of using them as weapons.

Even if I did trust an individual, an agency, or even a government to resist the temptation of threatening to use space-deployed nuclear explosives as weapons, things change. People die and are replaced, governments change (peacefully and otherwise).

So, don't expect me to sign a petition for maintaining a space-based fleet of nuclear explosives to quick-deploy against Earthbound impactors, or anything like that... I just don't think it would be a good idea.

-the other Doug

Wouldn't a nuclear-explosive-powered craft always have the issue of creating massive amounts of harmful radiation?

How did nuclear explosions come to take over the threads devoted to not one but two planets? Time for a special topic area?

Agreed - Doug moved some other speculative stuff to Nuking Europa
This stuff would probably be better off there.

There was a lot of discussion about Cassini's RTGs back in 1997...In the end it all went OK and everybody forget about it...
Now it's New Horizons turn to take the criticism.
I was wandering why NASA/JPL does not make some encasement for RTGs , some kind of protective shield during the launch. Something like titanium (or "allmost-unobtainium") casing that will be thrown away after it's safely out of earths orbit...If rocket explodes, RTG will stay in one piece and it will be found later. Or use some kind of escape tower like Russian Soyuz spacecraft...
Now I do know that any of these solutions would increase spacecrafts mass, but it will be much more safer. Just imagine how the PRESS would react if rocket explodes and highly radioactive plutonium falls down on Florida beaches...they would not be very sympathetic to NASA's goals of exploring some distant speck of light billions of miles away...

I'm not saying that they should do this on New Horizons, that is impossible but for future projects that should be considered...

When is it expected the final decision of the White house about the launch?

Whenever!
Final decision has allready been made...when they decided to spend half a billion dollars on it...
It's just some "Mister President has told us today to launch a probe to explore Pluto" thing...
Remember why are we going back to the Moon.............because Mr.President told us to...

Because of the RTG, NH still needs a formal approval from the Executive branch for launch. It may be a formality, but NH will not launch if the approval is not granted.

A post much earlier in this thread (or the other NH thread) said that the NH launch is a good thing because it was sending plutonium back to Pluto.

The RTGs used for over a couple of decades now already ARE very robust pieces of hardware. I remember reading about one launch failure where the rocket exploded and they located the missing RTG later, it was still intact. They refitted it to another satellite and flew it again, successfully!
The plutonium in the RTGs themselves is not in a metallic form which readily pulverizes, it's plutonium-oxide which doesn't pulverize violently in the case of an explosion so you're not likely to inhale it and die of accute radiation poisoning THAT easy.

All this media hype about radioactivity is an indicator just how poorly the writers of those articles are aware of actual facts...

The RTG does have a case intended to protect against impact damage that releases plutonium. This case is the outermost layer of protection. The fuel itself is in the form of ceramic pellets that are individually encased in an impact shell. Even if the rocket explodes in flight, the plutonium is not going to rain down on Florida. The major risk of plutonium release is the impact of the RTG with the ground breaking up the outer case and then damaging the inner impact shell of one or more fuel pellets.

The Environmental Impact Statement on the Pluto website describes the RTG, accident scenarios and probabilities. The piece by Grossman takes information from the EIS out of context to paint an unrealistic alarmist picture.

Thanks guys!!!
Of course I know that they are robust, but if they are encased in some protective casing during launch then it would be virtualy imposible to destroy them in case of rocket explosion or when they hit ground...so it would reasure public that it's not that dangerous...
Anyway you guys are right...
What's the name of that exploaded RTG carring satelite ugordan???

The problem with additional casing hardening is that the RTGs are pretty heavy as is and, really, it's not very feasible. Most of them have no chance of impacting on land anyway. Impacting into water is a much smaller shock.
I don't know what the name of the satellite was, but I seem to remember it was a U.S. military payload.