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A New Horizons Clone To 2003 Ub313?
Jyril
post Dec 22 2005, 06:42 PM
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QUOTE (SFJCody @ Dec 22 2005, 09:04 PM)
If 2003 UB313 has an albedo of ~70% (which seems to be the case given the difficulty in seeing it with Spitzer), it will have a surface slightly *brighter* than Proteus, even at 100AU.


At first try, Spitzer didn't detect 2003 UB313 because of a pointing error. Later observations haven't been published yet. But as the object is expected to have a Pluto-like or brighter surface, an albedo of 70% sounds reasonable.


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tasp
post Dec 22 2005, 06:47 PM
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QUOTE (ugordan @ Dec 22 2005, 10:14 AM)
Yeah, but sending the probe sharply above or below the ecliptic plane inherently diminishes the Jovian gravity assist, does it not? I'd think the biggest speed gain is when your outbound velocity is directed along Jupiter's orbital velocity, not upwards or below. That means the greates speeds achievable using gravity assists will be more or less in the ecliptic plane.
I guess...  unsure.gif
*


Not sure I've worked this out in my head correctly, but at a 45 degree angle to Jupiter equator, maximum grav assist would be around 71% of nominal.

And the angle allows a closer approach per a given radiation exposure. Angled to reach Pluto, (17 degree maximum) the grav assist would be almost maximum possible if timed properly.

Once a craft is on the trajectory to Jupiter, mass of the craft becomes irrelevant in regards to grav assist, btw.

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ugordan
post Dec 22 2005, 07:02 PM
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QUOTE (tasp @ Dec 22 2005, 07:47 PM)
Not sure I've worked this out in my head correctly, but at a 45 degree angle to Jupiter equator, maximum grav assist would be around 71% of nominal.

Isn't Jupiter's equator more or less edge on to the ecliptic? A 45 degree approach is bound to slinghot you way above/below the ecliptic.

QUOTE (tasp @ Dec 22 2005, 07:47 PM)
Once a craft is on the trajectory to Jupiter, mass of the craft becomes irrelevant in regards to grav assist, btw.

True, but the additional mass certainly counts when you're injecting the spacecraft to Jupiter in the first place. The fact Jupiter doesn't care how massive you are doesn't help your escape from an Earth parking orbit at all.


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SFJCody
post Dec 22 2005, 07:33 PM
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QUOTE (tasp @ Dec 22 2005, 06:47 PM)
Not sure I've worked this out in my head correctly, but at a 45 degree angle to Jupiter equator, maximum grav assist would be around 71% of nominal.

*


Why 45 degrees (except as a 'worst case')? 2003 UB313 isn't all that far from the ecliptic, and it's getting closer (it should pass through it before this century is out).

Edit: A thought about data transfer: At 100AU, the New Horizons clone would take years to downlink a 'Pluto encounter's worth' of data. A larger high-gain or optical communication may be needed.
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SFJCody
post Dec 23 2005, 11:28 AM
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This is beginning to resemble the TAU (thousand astronomical unit) mission conceived in the mid 80s.


Bulletin of the American Astronomical Society, Vol. 18, p.1012 (09/1986)


Edit: Scientifically, a mission to 2003 UB313 (or 2005 FY9, which might be more Pluto-like) would be a useful counterpart to New Horizons. New Horizons will pass Pluto a few decades past perihelion, complete with atmosphere/outgassing/geysers/etc. But unless we are still around in a century's time we won't get to see it in its more quiescent aphelion state. Luckily, Pluto's cousin TNOs are close to aphelion (which is probably why they escaped detection for so long).
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Guest_BruceMoomaw_*
post Dec 24 2005, 01:45 AM
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This seems to be the type of mission that can ONLY be done either by a solar sail or by nuclear-electric propulsion. (I know which one I'd prefer.)

http://trs-new.jpl.nasa.gov/dspace/bitstre...9/1/99-0394.pdf
http://trs-new.jpl.nasa.gov/dspace/bitstre...7/1/99-1367.pdf
http://trs-new.jpl.nasa.gov/dspace/bitstre...9/1/99-1857.pdf
http://trs-new.jpl.nasa.gov/dspace/bitstre...4/1/01-0122.pdf
http://trs-new.jpl.nasa.gov/dspace/bitstre...0/1/00-1293.pdf
http://trs-new.jpl.nasa.gov/dspace/bitstre...4/1/00-0010.pdf
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Comga
post Dec 24 2005, 06:09 AM
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QUOTE (SFJCody @ Dec 23 2005, 05:28 AM)
This is beginning to resemble the TAU (thousand astronomical unit) mission conceived in the mid 80s.
*


Wow. Thanks for dredging up the TAU document. What a blast from the past! It is hard to think how ideas so far out were being discussed in those days. This topic is about as close as we come these days.
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edstrick
post Dec 24 2005, 10:02 AM
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The "Purple Pigeons of Planetology" Wish List. Don't remember them all, but things like Rosetta and Cassini are in that category.
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ilbasso
post Dec 24 2005, 10:44 PM
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At what angle and distance did Ulysses encounter Jupiter to be shot into an 80-dgree inclided orbit?


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Planet X
post Jan 9 2006, 11:59 AM
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I was looking at the planetary orbits (as viewed from 90 degrees above the ecliptic) the other day and noticed it might be possible to fly a Uranus-2003 UB313 mission. Just wondering, is the NH2 concept dead? If not, would it be possible to fly that mission to Uranus and 2003 UB313? That, IMO, would be one cool mission. Has anyone yet pondered this idea? Later!

J P
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abalone
post Jan 9 2006, 01:54 PM
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QUOTE (ugordan @ Dec 23 2005, 06:02 AM)
Isn't Jupiter's equator more or less edge on to the ecliptic?
*

It is not Jupiter's equator or the ecliptic that matter it is the plane of the planets orbit. It just so happens that for Jupiter they are almost the same. For Uranus it matters of course if it is to be used for grav assist

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Planet X Posted Yesterday, 10:59 PM
At what angle and distance did Ulysses encounter Jupiter to be shot into an 80-dgree inclided orbit?


If a gravity assist is an increase in velocity then this may not qualify as if was simply using Jupiter to change the inclination of the orbit, but then again that is a deltaV so it may. unsure.gif unsure.gif unsure.gif
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ugordan
post Jan 9 2006, 02:09 PM
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QUOTE (abalone @ Jan 9 2006, 02:54 PM)
It is not Jupiter's equator or the ecliptic that matter it is the plane of the planets orbit. It just so happens that for Jupiter they are almost the same. For Uranus it matters of course if it is to be used for grav assist
*

I think you misunderstood me. What I was getting at is that most planets (well, all when you exclude Pluto tongue.gif) orbit in practically the same plane. Jupiter's equatorial plane is also similar to that plane meaning the most intense radiation area around Jupiter is "conveniently" placed so most spacecraft that want to reach one of those planets need to fly through the densest part of the radiation belt IF they want to maximize the slingshot effectiveness, that is fly as close to Jupiter as possible.


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abalone
post Jan 9 2006, 02:29 PM
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QUOTE (ugordan @ Jan 10 2006, 01:09 AM)
I think you misunderstood me. What I was getting at is that most planets (well, all when you exclude Pluto tongue.gif) orbit in practically the same plane. Jupiter's equatorial plane is also similar to that plane meaning the most intense radiation area around Jupiter is "conveniently" placed so most spacecraft that want to reach one of those planets need to fly through the densest part of the radiation belt IF they want to maximize the slingshot effectiveness, that is fly as close to Jupiter as possible.
*

Got it, thanks
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Bob Shaw
post Jan 9 2006, 09:48 PM
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QUOTE (SFJCody @ Dec 22 2005, 08:33 PM)
Why 45 degrees (except as a 'worst case')? 2003 UB313 isn't all that far from the ecliptic, and it's getting closer (it should pass through it before this century is out).

Edit: A thought about data transfer: At 100AU, the New Horizons clone would take years to downlink a 'Pluto encounter's worth' of data. A larger high-gain or optical communication may be needed.
*



I think it was Bruce Moomaw who commented on a related issue, ie the cost per unit of data, and suggested that future spacecraft needed to be examined on an accounting basis as well as in terms of pure science (I wonder how the ISS would come out? NOT!). It does make you think, though, that with spacecraft longevity almost a given, s-l-l-l-o-o-o-w data return might have a range of benefits. Smaller spacecraft sizes, more robust components, and cheaper radio facilities on Earth all spring to mind. Does it *really* matter if the results of a wham-bang-thankyou-ma'am encounter take years to be returned?

Bob Shaw


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helvick
post Jan 9 2006, 10:18 PM
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QUOTE (Bob Shaw @ Jan 9 2006, 10:48 PM)
Smaller spacecraft sizes, more robust components, and cheaper radio facilities on Earth all spring to mind. Does it *really* matter if the results of a wham-bang-thankyou-ma'am encounter take years to be returned?
*

We're going to need an orbiting deep space receiver to handle all this inbound data fairly soon. The Earth\Moon L4\L5 points seem like a good spot. Are there any plans?
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