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The case for more flybys
TheAnt
post Jul 11 2015, 06:17 PM
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QUOTE (belleraphon1 @ Jul 11 2015, 07:44 PM) *
I really do not see this as an end to classical exploration. We are opening a new door. It never ends...

Craig


I concur, this is only the later part of a first survey of some of the major stops in the solar system, but not all.

Though all big stops have been covered with a first peek, we cant say we have visited a place after seeing it trough a window of a high speed train. And NH can be compared to that to one amazing degree. =)
Even by a simple flyby we still got Pallas, the Trojans of Jupiter, Chiron, Haumea, Ixion, Makemake, Orcus, Sedna, Quaoar and Varuna before we even will see the end of the first survey.
When all these worlds have had a visit by a lander or one atmospheric probe, then I will agree we've come to the end of 'classical exploration' and start to think about what kind of rovers that would be suitable for Varuna or Io. =)

And thank you for the 2 images fredk, yes I did show those to a friend and we could see the slight difference in size from only 4 minute, that really put some perspective on how fast NH is travelling. =)
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belleraphon1
post Jul 11 2015, 06:38 PM
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QUOTE (TheAnt @ Jul 11 2015, 02:17 PM) *
I concur, this is only the later part of a first survey of some of the major stops in the solar system, but not all.


Agree ....first pass ... and what a wonderland has been revealed.

Still want to hear the winds whisper on Mars. What does a human breath sound like there?
What sonorous bells ring in the caverns of Enceladus?
What vapours rise from the hollows on Mercury?
Does a wind stir the anvil plains of Venus?
What electric dreams stir the rad belts of Jupiter and what would a skyfall reveal of the interior?
Do diamonds really rain on Uranus and Neptune?
Do whales sing in the oceans of Europa?
What hydrocarbon magic occurs in the cauldron of Titan seas?

What awaits in the outer dark and across the stygian sky?

We have just started.

Craig.
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rboerner
post Jul 11 2015, 06:41 PM
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There has been a slightly off-topic sub discussion in the New Horizons Pluto System Encounter about the merits of additional KBO flybys.

Some people seem to think that the age of flybys is over with NH. I don't quite see the logic in that. The diversity of KBOs calls for additional samples. One cheap NH-type craft could encounter Jupiter, Uranus or Neptune and then one or even two KBOs. Explore additional KBOs, get ice giants and perhaps Triton for free.

Given that new ice giant exploration with orbiters may not be happening until the 2040s, this seems like an incredibly good deal for a $700 million mission.

Uranus should count as a "new" planet not previously visited anyway because it is approaching the opposite solstice (2028) than the one Voyager 2 encountered in 1986, so a flyby probe would image the northern hemispheres of the Uranian satellites for the first time.



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rboerner
post Jul 11 2015, 06:57 PM
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Something to add: I know the idea is quite obvious. Alan Stern proposed it as New Horizons II and it was rejected.

http://blogs.discovermagazine.com/outthere...plutos-wonders/
https://en.wikipedia.org/wiki/New_Horizons_2

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ZLD
post Jul 11 2015, 06:58 PM
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One of the biggest hurdles for any of these outer planets missions will be in getting enough Plutonium-238 to power the craft. Much of this ceased production as nuclear weaponry slowed in production. This(pdf) link has a good overview of the current situation with powering spacecraft in the outer planets.

It isn't necessarily just that people don't want a flyby mission. It also has some to do with 'wasting' an extremely rare resource for a very limited science return, versus a mission like Cassini which has generated an enormous sum of data for over 11 years.

Don't get me wrong, if Pu-238 was plentiful again, a bunch of NH class missions would be great, so long as it didn't jeopardize the science return for other longer missions.


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OWW
post Jul 11 2015, 06:59 PM
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QUOTE (belleraphon1 @ Jul 11 2015, 07:38 PM) *
What does a human breath sound like there?

We already know.

Less than 2 million miles now!
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nprev
post Jul 11 2015, 07:02 PM
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Topic moved to the Exploration Strategy section. Please review the Forum rules and keep them firmly in mind before posting.


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A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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rboerner
post Jul 11 2015, 07:08 PM
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At the risk of derailing my own thread, what are the odds that NASA will try to ease the PU 238 shortage by restarting development of ASRG? The latest news I'm aware of on the subject,

http://spacenews.com/u-s-plutonium-stockpi...fter-mars-2020/

says that ASRG development isn't truly dead, just on the minimum funding back burner and could be revived.
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djellison
post Jul 11 2015, 07:52 PM
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QUOTE (rboerner @ Jul 11 2015, 10:41 AM) *
One cheap NH-type craft ....


$650M isn't cheap - New Horizons was New Frontiers class. Only Flagship missions are more expensive. Unless you are actually building them at the same time, there is little to be saved by building any sort of copy.

New Frontiers missions are now in the region of $800M - and given the current budget environment, expecting more than two every decade could be considered highly optimistic.
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ZLD
post Jul 11 2015, 08:35 PM
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The ASRG is a good concept. I like it because it produces a lot more power for the same fuel supply. I don't like it because moving parts inherently fail eventually without maintenance. Most units will probably be fine (should they go into use) but a few are likely to cripple a mission and that always stings.


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JRehling
post Jul 23 2015, 06:49 PM
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I'll mention an idea I had 15 years ago and the extension of that idea from the asteroid belt to the Kuiper Belt.

The high concept for the asteroid belt was this: Use a Jupiter gravity assist to put a solar orbiter into retrograde orbit. Use propulsion to drop the aphelion in from Jupiter distance to the edge of the asteroid belt. Then fly "backwards" down the asteroid belt, like a lunatic driving the wrong way down the highway, and have many, many asteroid flybys which are each very fast, because the relative velocity of the craft vs. the asteroids would be double the orbital speed at that distance.

Would a random orbit like that provide many close fly-bys? No. But if the goal were to maximize flybys, choosing whichever targets provided that goal, there could be an extraordinary number of fly-bys, as it would experience a conjunction with a known asteroid on average every two hours. Of course, most of these would be terribly distant flybys, but there would be a huge number of trajectories that would provide targeted flybys of 3 asteroids in a half orbit, and a few moderately close untargeted flybys. Then a propulsive maneuver could set up another set of targeted flybys, and I think you could get pretty good science on dozens of asteroids in one mission.

The Kuiper Belt doesn't make any of that math work out so nicely, but I suspect that a NH clone could achieve 3-5 flybys if we weren't picky about which targets it flew by. NH itself was "married" to one target. If a KB Explorer used a Neptune gravity assist to fly by two chosen targets, there'd almost certainly be a third bonus target reachable after that, so we'd get a look at the Neptune system plus 3 KBOs. Uranus could also drive something like that, and with two more probes, we'd get a flyby of Uranus and Neptune plus about 6 KBOs.
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SFJCody
post Jul 23 2015, 07:02 PM
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One thing I'd like to see for a future New Horizons style mission is an attempt to draw out the flyby by giving the spacecraft a larger aperture telescope. Imagine how great it would be to have a mission with a HiRISE size instrument. Or even WFIRST!
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stevesliva
post Jul 23 2015, 07:13 PM
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QUOTE (djellison @ Jul 11 2015, 02:52 PM) *
Unless you are actually building them at the same time, there is little to be saved by building any sort of copy.


2 is a good number. One J-U-TNO and one J-N-TNO. Same hardware, staggered so the same ops team handles every flyby. One "mission," two spacecraft, 4 giant planet flybys, then TNO science.

The problem is you get a smidge of science in a wide variety of buckets, so it's hard to write mission objectives for such a thing that sells it as advancing science in the way these things are justified.
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JRehling
post Jul 23 2015, 09:08 PM
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I suppose one could group the Uranian and Neptunian satellites with TNOs as one, broad class of body that the mission(s) are exploring, just as Dawn had Vesta and Ceres as co-targets, not two unrelated goals. But Jupiter, jovian system (and Uranus/Neptune) observations would be quite unrelated: Nice to have, but not a rationale for the mission.
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stevesliva
post Oct 6 2015, 09:31 PM
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QUOTE (JRehling @ Jul 23 2015, 05:08 PM) *
I suppose one could group the Uranian and Neptunian satellites with TNOs as one, broad class of body that the mission(s) are exploring, just as Dawn had Vesta and Ceres as co-targets, not two unrelated goals. But Jupiter, jovian system (and Uranus/Neptune) observations would be quite unrelated: Nice to have, but not a rationale for the mission.


Probably true. Looking at the new geology coming from the Pluto flyby, I'd think ice giant satellite flybys are not the un-novel already-been-done thing we tend to think of them as. The excellent may be the enemy of the good.
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