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exobioquest
After pluto and any other KBO its set to intercept, how far can NH go before it dies on use? Can it reach the heliopause? Does it have any means of analyzing the heliopause and interstellar wind beyond it?
nprev
Just to add another question, have any candidate KBOs been identified for NH yet?
alan
I wouldn't expect them to pick a KBO target right away. There are a couple of new survey telescopes under development which will significantly increase the options while New Horizons in on the way to Pluto. This one for example PAN-STARRS, projected to begin in 2009, is expected to find 20,000 KBO's.
edstrick
They said on a press breifing today that they'd start the active search for KB objects about 2012. Post Pluto-encounter, the delta-V capability with the expected onboard fuel is a 1/10 degree wide cone expanding from the point of pluto-intercept. It's not worth the effort to search now for KB objects that will be in that narrow cone after 2015, when things like the Synoptic Survey Telescope will be deep-scanning the sky for KB objects by the hundreds of thousands and more.
nprev
QUOTE (edstrick @ Jan 15 2006, 11:41 PM)
They said on a press breifing today that they'd start the active search for KB objects about 2012.  Post Pluto-encounter, the delta-V capability with the expected onboard fuel is a 1/10 degree wide cone expanding from the point of pluto-intercept.  It's not worth the effort to search now for KB objects that will be in that narrow cone after 2015, when things like the Synoptic Survey Telescope will be deep-scanning the sky for KB objects by the hundreds of thousands and more.
*



I see; thanks, Ed and Alan.

Makes sense; Pluto doesn't have enough mass to alter the spacecraft's course to any significant degree (ta-da, da!) smile.gif
abalone
QUOTE (edstrick @ Jan 16 2006, 05:41 PM)
They said on a press breifing today that they'd start the active search for KB objects about 2012.  Post Pluto-encounter, the delta-V capability with the expected onboard fuel is a 1/10 degree wide cone expanding from the point of pluto-intercept.  It's not worth the effort to search now for KB objects that will be in that narrow cone after 2015, when things like the Synoptic Survey Telescope will be deep-scanning the sky for KB objects by the hundreds of thousands and more.
*

I think it is a bit more than that. Delta V of say 100-150m/s when travelling at 13km/s equates to a cone of more like 1 deg rather than 1/10 deg
edstrick
"....Pluto doesn't have enough mass to alter the spacecraft's course to any significant degree ...."

Even if it did.... the trajectory past Pluto is almost 100% "constrained". Primary mission science goals REQUIRE radio occultation by BOTH Pluto and Charon. There is essentially one trajectory that can give that result, with the main variation being which 6 1/2 <is that right> orbit of Chiron around Pluto puts it into the right position for the second occultation.
abalone
Quick calculation. Max Delta V anticipated is about 210 m/s, this post Pluto-encounter wide cone expanding from the point of pluto-intercept of almost exactly 2.0 deg. Compare this to the moon as visble from Earth being about 1/2 deg.

That makes a cone 4X that apparaent diameter of the moon. The reason they are not searching yet is twofold.

1. they dont know where that cone will be until after launch
2. just as importantly, even after launch and the cone can be determined, where do you search for an object that will be in this cone in 9 years time. That of course depends on its orbit. The longer you leave the search, the smaller the area that needs to be searched
Holder of the Two Leashes
QUOTE (edstrick @ Jan 16 2006, 12:41 AM)
They said on a press breifing today that they'd start the active search for KB objects about 2012.  Post Pluto-encounter, the delta-V capability with the expected onboard fuel is a 1/10 degree wide cone expanding from the point of pluto-intercept.  It's not worth the effort to search now for KB objects that will be in that narrow cone after 2015, when things like the Synoptic Survey Telescope will be deep-scanning the sky for KB objects by the hundreds of thousands and more.
*


When they do start that search, Pluto (and any KBO targets) will be smack in the middle of the milky way in Sagitarius. This is an area normally avoided by planetoid hunters in the past, because of the dense star field. I wonder how they're going to address this issue? You need very good resolution, on the order of nearly perfect seeing from the ground, to pull anything out of the background.
ToSeek
QUOTE (Holder of the Two Leashes @ Jan 16 2006, 03:52 PM)
When they do start that search, Pluto (and any KBO targets) will be smack in the middle of the milky way in Sagitarius. 


Just because Pluto is there, does that mean that any KBO NH can fly by must also be there? I would think that with a years-long cruise ahead of it, there's a wide swath where a possible KBO could be, if it's at the right distance.
ljk4-1
QUOTE (ToSeek @ Jan 16 2006, 02:31 PM)
Just because Pluto is there, does that mean that any KBO NH can fly by must also be there? I would think that with a years-long cruise ahead of it, there's a wide swath where a possible KBO could be, if it's at the right distance.
*


Here's some real heresy: Why flyby Pluto when more interesting KBOs will likely be discovered between now and 2015? Can NH be retargeted for them? How about some of the interesting ones we know now, including the one that is bigger than Pluto (I will NOT say its unofficial name)? I think we should use Jupiter to whip NH out of the ecliptic to it.
abalone
QUOTE (ToSeek @ Jan 17 2006, 06:31 AM)
years-long cruise ahead of it, there's a wide swath where a possible KBO could be, if it's at the right distance.
*

Yes that is true but the wide swath where a possible KBO could is all will be smack in the middle of the milky way in Sagitarius. It is not until about 2011 that the target field has moved into a more favorable location
Holder of the Two Leashes
QUOTE (ToSeek @ Jan 16 2006, 01:31 PM)
Just because Pluto is there, does that mean that any KBO NH can fly by must also be there? I would think that with a years-long cruise ahead of it, there's a wide swath where a possible KBO could be, if it's at the right distance.
*



New Horizons will not have many years to live after Pluto, so the KBO's have to be fairly close. They didn't get as much plutonium as they wanted for the RTGs, and there was some question early on as to whether the spacecraft would be at full power even at Pluto. Even if the rendezvous point with the KBO clears the milky way, the object is not stationary in the sky and will have moved there from a point that was in a fairly dense sky background (unless it's in some very weird retrograd orbit). You need to have located it by the time NH reaches Pluto in order for a course change to have maximum effect.
ljk4-1
QUOTE (Holder of the Two Leashes @ Jan 16 2006, 04:13 PM)
New Horizons will not have many years to live after Pluto, so the KBO's have to be fairly close.  They didn't get as much plutonium as they wanted for the RTGs, and there was some question early on as to whether the spacecraft would be at full power even at Pluto.  Even if the rendezvous point with the KBO clears the milky way, the object is not stationary in the sky and will have moved there from a point that was in a fairly dense sky background (unless it's in some very weird retrograd orbit).  You need to have located it by the time NH reaches Pluto in order for a course change to have maximum effect.
*


Any other gas giant planets conveniently along the way where NH could get an extra boost?
mchan
QUOTE (ljk4-1 @ Jan 16 2006, 01:15 PM)
Any other gas giant planets conveniently along the way where NH could get an extra boost?
*

After Jupiter, there are no gas giants to help further on the way to Pluto. Beyond Pluto, there are no known gas giants. It would be fantastic if a gas giant were to found beyond Pluto and that would be in the narrow cone of possble post-Pluto trajectories.
AlexBlackwell
QUOTE (ljk4-1 @ Jan 16 2006, 07:37 PM)
Here's some real heresy:  Why flyby Pluto when more interesting KBOs will likely be discovered between now and 2015?  Can NH be retargeted for them?  How about some of the interesting ones we know now, including the one that is bigger than Pluto (I will NOT say its unofficial name)?  I think we should use Jupiter to whip NH out of the ecliptic to it.
Aside from the power issues mentioned previously, your idea, in addition to being "heresy," doesn't make a whole lot of scientific sense. The Pluto flyby alone will allow for exploration of four KBOs (Pluto, Charon, S/2005 P1 and S/2005 P2). You want to give up that opportunity to fly to a "more interesting" (whatever that means) KBO? And one that is further away?
AlexBlackwell
QUOTE (mchan @ Jan 16 2006, 09:52 PM)
After Jupiter, there are no gas giants to help further on the way to Pluto.  Beyond Pluto, there are no known gas giants.
Yeah, I seem to recall from Astronomy 101 the following progression: Jupiter, Saturn, Uranus, Neptune, and then Pluto tongue.gif
exobioquest
Hey, be nice and answer stupid question like they are smart ones, respect the retarded and you will be blessed with good karma. wink.gif

So what’s the max life span of NH? Expected to die in?... 2020,2025,2030, when? How much power would it need to run a minimum of instruments (say for heliopause observations, if any instrument on board can do that)? How far would it get roughly by then?
abalone
QUOTE (exobioquest @ Jan 17 2006, 04:21 PM)
Hey, be nice and answer stupid question like they are smart ones, respect the retarded and you will be blessed with good karma.  wink.gif

So what’s the max life span of NH? Expected to die in?... 2020,2025,2030, when? How much power would it need to run a minimum of instruments (say for heliopause observations, if any instrument on board can do that)? How far would it get roughly by then?
*

Just roughly from memory.
Power at launch is just over 200w and it degrades at 3.5w/year. Minimum power required to operate is 100w? I dont know what it will be able to run on this. So lifespan about 25 years.

Even at Pluto flighby it will be down to about 190-200w and not enough to run all instruments at the same time
Analyst
Power at Launch is about 240w. I believe Alan Stern posted here 190w are needed to operate including the science instruments (encounter). No idea about the minimum power needed just to live.
djellison
QUOTE (abalone @ Jan 17 2006, 06:53 AM)
Even at Pluto flighby it will be down to about 190-200w and not enough to run all instruments at the same time
*


I dont think you've got that right. If you go back and read Alan's PI-Persp's, I see no mention of rolling instrument operation a-la Voyager.

Doug
edstrick
My understanding is that they were able to get more plutonium than they expected to after all the security-screwup work-stoppages at Los Alamos, but they didn't get a full load. I think they're able to do 100% duty cycle at Pluto, but the further out a KB object they flyby is, the more they'll have to cycle power usage as the levels decline.

There's also probably some small uncertainty on the degradation rate of the RTG. The half life of the plutonium is pretty well known, but much of the degradation is due to radiation damage of the bimetallic junctions in the thermocouples that generate power, and that's going to be very hardware dependent. This is a spare.. was it from Cassini?.. so that should be pretty well but not perfectly known.
abalone
QUOTE (djellison @ Jan 17 2006, 07:58 PM)
I dont think you've got that right.  If you go back and read Alan's PI-Persp's, I see no mention of rolling instrument operation a-la Voyager. 

Doug
*

It may be wrong or out of date but here is where I got the info

http://www.spaceflightnow.com/atlas/av010/...spacecraft.html
QUOTE
Typical of RTG-based systems, as on past outer-planet missions, New Horizons does not have a battery for storing power. At the start of the mission, the RTG will supply approximately 240 watts (at 30 volts of direct current) - the spacecraft's shunt regulator unit maintains a steady input from the RTG and dissipates power the spacecraft cannot use at a given time. By July 2015 (the earliest Pluto encounter date) that supply decreases to 200 watts at the same voltage, so New Horizons will ease the strain on its limited power source by cycling science instruments during planetary encounters.
David
QUOTE (ljk4-1 @ Jan 16 2006, 07:37 PM)
Here's some real heresy:  Why flyby Pluto when more interesting KBOs will likely be discovered between now and 2015?  Can NH be retargeted for them?  How about some of the interesting ones we know now, including the one that is bigger than Pluto
*


Pluto is still the most interesting KBO out there -- if only because we know a little bit more about it than the other ones. I think that a very distant, very cold, rather small planet that still somehow manages to have an atmosphere has got to have interesting things going on on it.
edstrick
It's not really a practical target untill we can lob something bigger considerably faster, but Sedna is going to eventually be a very high priority target.. Much further out, with orbital dynamics that suggest a radically different origin is possible (possible capture during stellar flyby as the star forming region the solar system formed in broke up). If nothing else, Sedna's been in a deeper freeze than anything we know other than Oort cloud comets.
belleraphon1
Right now the Pluto/Charon binary planet is the most interesting KBO. And it should indeed remain the focus for New Horizons.... one of the big attractions at Pluto is the presence of an atmosphere that is slowly freezing out.

Note this report form
http://www.spaceref.com/news/viewpr.html?pid=18769

Researchers have identified spectral features that hint at possible atmospheres on
2003 UB313 and 2005 FY9.

As for what we will find out there in the Kuiper Belt as NH heads out ..... I have read some reports that believe there could be Earth sized KBO's out there....

Craig
ljk4-1
This thread discussed the theory that no really large KBOs exist:

http://www.unmannedspaceflight.com/index.php?showtopic=1546

Of course we won't know for certain until we can send some dedicated KBO probes out there.

I certainly understand that Pluto is the best known of all the KBOs, but I get the feeling there are even more interesting ones out there. Their only "flaw" is that they are more distant from Earth.
djellison
Pluto gives us 4 bodies for the price of one, that we know to be reachable, targetable, and interesting.

To even entertain the idea of targetting elsewhere is just crazy.

Doug
ljk4-1
QUOTE (djellison @ Jan 17 2006, 10:40 AM)
Pluto gives us 4 bodies for the price of one, that we know to be reachable, targetable, and interesting.

To even entertain the idea of targetting elsewhere is just crazy.

Doug
*


I was referring in my most recent post to later probe missions with more power, better instruments, and a future improved astronomical knowledge of other KBOs.

We are just touching the tip of the iceberg with KBOs right now. And let's not forget the Oort Cloud, of which we know even less. Literally billions of worlds out there to explore, ones presumably untouched since the formation of the Sol system.

Pluto and its moons are just for starters.

Would this be the place to discuss what we would need in a probe to properly explore multiple KBOs?
mchan
QUOTE (edstrick @ Jan 17 2006, 01:38 AM)
My understanding is that they were able to get more plutonium than they expected to after all the security-screwup work-stoppages at Los Alamos, but they didn't get a full load.  I think they're able to do 100% duty cycle at Pluto, but the further out a KB object they flyby is, the more they'll have to cycle power usage as the levels decline. 
*

Since NH is going by Pluto anyways, can't it pick up some more plutonium there?

(Ducks)
abalone
QUOTE (mchan @ Jan 18 2006, 06:23 AM)
Since NH is going by Pluto anyways, can't it pick up some more plutonium there?

(Ducks)
*

No. It does not have any landing capability and no-one to open the bonnet
Bob Shaw
QUOTE (mchan @ Jan 17 2006, 08:23 PM)
Since NH is going by Pluto anyways, can't it pick up some more plutonium there?

(Ducks)
*



Yes, and your point about Donald *was*?

(REALLY ducks - and hides!)

Bob Shaw
Jeff7
Ok guys, stop being Goofy!


*also ducks*
punkboi
QUOTE (Jeff7 @ Jan 17 2006, 04:50 PM)
Ok guys, stop being Goofy!
*also ducks*
*


You guys seem too hyper. Let me slip you a Mickey.

*Really really really ducks*
exobioquest
ooooooooooookkkkkkkkkyyyyyyyyy...

so how long will NH last and how far could it get?

(fires alot of mortor rounds)
dvandorn
QUOTE (punkboi @ Jan 17 2006, 08:00 PM)
You guys seem too hyper.  Let me slip you a Mickey.

*Really really really ducks*
*

This isn't really a full-fledged pun war. It's more of a Minnie-war.

*ducks faster than you can scrub a launch attempt*

-the other Doug
edstrick
beware of quantum ducks: QUARK! QUARK!
Bart
Sorry to hijack this thread back to something serious, but... rolleyes.gif

I was looking at a plot of where stuff is in the outer solar system at http://cfa-www.harvard.edu/iau/lists/OuterPlot.html (link provided so graciously by edstrick on the Pioneer/Asteroid Belt thread), and I noticed that there is a big gap in the Kuiper Belt right where New Horizons is headed.

Is this some kind of an observational bias, or is there a real dynamic effect, some kind of scattering by Neptune, that is clearing out the exact part of the belt that we're going to visit? Does this mean that NH is less likely to find a big juicy target after Pluto?

Bart
Alan Stern
That's just an observational effect. NH is headed toward Sagitarius, the galactic center.
The starfields are dense there, so observers avoid them to ease their needle
in the haystck hassles in finding KBOs. The KB itself has no such gap.

-Alan
Alan Stern
QUOTE (Alan Stern @ Jan 21 2006, 02:04 AM)
That's just an observational effect. NH is headed toward Sagittarius, the galactic center.
The starfields are dense there, so observers avoid them to ease their needle
in the haystck hassles in finding KBOs. The KB itself has no such gap.

-Alan
*
edstrick
A random note on that outer planets plot: There is a lot of "structure" in the Kuiper belt that consists of approximately radial lines of objects separated by zones with fewer objects. This is an amusing selection effect... wher objects were found in a deep search, separated by areas where the search wasn't as deep.

Even more amusnig....some of the line-ups are NOT radial toward the sun.... because the inner objects have moved slightly further in their orbits since that radial zone of objects was discovered than the objects further out.
Holder of the Two Leashes
Perhaps now would be a good time to reask a question I asked earlier:

QUOTE (Holder of the Two Leashes @ Jan 16 2006, 09:52 AM)
When they do start that search, Pluto (and any KBO targets) will be smack in the middle of the milky way in Sagitarius.  This is an area normally avoided by planetoid hunters in the past, because of the dense star field.  I wonder how they're going to address this issue?  You need very good resolution, on the order of nearly perfect seeing from the ground, to pull anything out of the background.
*
stevesliva
QUOTE (edstrick @ Jan 21 2006, 04:33 AM)
Even more amusnig....some of the line-ups are NOT radial toward the sun.... because the inner objects have moved slightly further in their orbits since that radial zone of objects was discovered than the objects further out.
*

I find the animation of the orbits of the discovered objects to be amusing:
http://cfa-www.harvard.edu/iau/Animations/OuterSmall.gif

Lots of comets that were discovered in the inner solar system extrapolated back in time... very clearly indicating how much must be undiscovered.
stevesliva
QUOTE (Holder of the Two Leashes @ Jan 21 2006, 02:48 PM)
Perhaps now would be a good time to reask a question I asked earlier:
*

http://en.wikipedia.org/wiki/Pan-STARRS ... apparently will be able to find just about anything that moves.
ljk4-1
In Arthur C. Clarke's novel The Hammer of God, a bomb is detonated that reveals where every minor body is in the Sol system. I cannot remember the details much beyond this, can someone help here and would such a plan be feasible?

http://en.wikipedia.org/wiki/The_Hammer_of_God
just-nick
QUOTE (stevesliva @ Jan 21 2006, 04:20 PM)
http://en.wikipedia.org/wiki/Pan-STARRS ... apparently will be able to find just about anything that moves.
*


And, pending funding, there's this even bigger bad boy:

LSST

Though I do take points away for the name.

--Nick
Holder of the Two Leashes
QUOTE (stevesliva @ Jan 21 2006, 05:20 PM)
[ ... apparently will be able to find just about anything that moves.
*


Thank you, stevesliva. I read the article, and found it interesting in several respects. I always consider Wikipedia a little suspect, but I have no reason to believe that anything in particular in this article is not factual.

However, the problem here is one of pulling faint (mag 22-24) objects out of a somewhat bright background. At 1 to 2 arc sec resolution, as I'm assuming these telescopes will have, you are seeing small variations in brightness as the KBOs move around over the milky way, rather than faint but distinct objects moving over a black starry background. Within the Wikipedia article, it mentioned that times around full moon would have to be avoided because of the brightly lit sky. The milky way forms a kind of permanent nearly "full moon" type sky in it's location, and it's at it's widest and brightest near Sagittarius.

I'm wondering how even Pan-STARRS will cope with the background noise. Hubble, I'm sure, has the resolution, but it's field of view is too narrow to do the kind of survey required.
SFJCody
There's a ppt about the search problems here:
http://www.boulder.swri.edu/~spencer/nhkbo...kbofind4web.ppt
Holder of the Two Leashes
QUOTE (SFJCody @ Jan 22 2006, 03:15 AM)
There's a ppt about the search problems here:
*


That's exactly the sort of summary I was looking for. However, having read it, I'm still a little unsettled.

An overview of the conclusions seems to be this: "We're pretty sure we can do this, by brute force if necessary. There's going to be better technology and techniques down the road in any case. There are some dust lanes in some search areas that won't be so bad. And maybe it WOULD be a good idea to use Hubble on occasion."

Ooookaaayyy. I say good hunting to them. I mean that sincerely.

(And I'll be back in a few years to say I always had faith in them)
john_s
QUOTE (Holder of the Two Leashes @ Jan 22 2006, 07:15 PM)
Ooookaaayyy.  I say good hunting to them.  I mean that sincerely. 

(And I'll be back in a few years to say I always had faith in them)
*


Thanks for the good wishes! Your summary is fairly accurate, though Hubble's of limited use for the search because of its small field of view. Though once we've found some candidates, Hubble may be able to help up pin down their orbits. Pan-STARRS has a wide field of view but is limited by its fairly small aperture. We're counting on big telescopes with big cameras to do this job right. We already have a bunch of data from the Subaru telescope, covering the search area with fairly short exposures, in case there are some particularly bright targets, and we're grinding through that data now. Fortunately we've got nine years before we need the results from the full survey.

John Spencer.
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