New Horizons: Pre-launch, launch and main cruise, Pluto and the Kuiper belt Options

[Alan Stern]

...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

[tasp]

...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 evoid 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'lll 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).

[Alan Stern]

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

[tasp]

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.

[Guest_BruceMoomaw_*]

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).

[Decepticon]

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.

[Toma B]

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




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"...

[ugordan]

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...

[ljk4-1]

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




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"...

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

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[paxdan]

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

[ugordan]

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

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.

[ljk4-1]

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.

[BPCooper]

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.

[dilo]

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.

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):

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[Comga]

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"...

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?