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Neptune Orbiter, Another proposed mission
Rob Pinnegar
post Nov 10 2005, 03:51 PM
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This seems like a good place to start off the Uranus and Neptune forum: with the next ice-giants mission.

I will admit to not knowing a whole lot about the Neptune Orbiter With Probes (NOWP), other than the fact that it's in the planning stages, and a few other details I've gathered from Wikipedia and various other Internet sources. Anyone care to get this one going with a bit more information?
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Guest_Analyst_*
post Jul 20 2006, 10:54 AM
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Before the "nuclear problem" comes the money problem. RTGs may be expensive, but they are very reliable, long lasting with predictable slow degration. Solar arrays at Neptune? There you have 1/36 the light level compared to Jupiter, this means 36 times larger arrays (or collector space). I guess this will be more expensive than RTGs (at least to develop), much less reliable and a problem for navigating/pointing.

Save the money problem first.
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antoniseb
post Jul 21 2006, 11:52 PM
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QUOTE (Analyst @ Jul 20 2006, 04:54 AM) *
Before the "nuclear problem" comes the money problem. RTGs may be expensive, but they are very reliable, long lasting with predictable slow degration. Solar arrays at Neptune? There you have 1/36 the light level compared to Jupiter, this means 36 times larger arrays (or collector space). I guess this will be more expensive than RTGs (at least to develop), much less reliable and a problem for navigating/pointing.

Save the money problem first.


Your mention of the factor of 36 difference in Sun light compared to Jupiter seems to have ignored the previous post. It would be fairly cheap and reliable to have thousands of square meters of mylar reflecting light back to a small PV array.
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Stephen
post Jul 25 2006, 04:35 AM
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QUOTE (antoniseb @ Jul 21 2006, 11:52 PM) *
Your mention of the factor of 36 difference in Sun light compared to Jupiter seems to have ignored the previous post. It would be fairly cheap and reliable to have thousands of square meters of mylar reflecting light back to a small PV array.

But is it a practical solution?

Once you got to Neptune and started orbiting the planet you would need to ensure that all that mylar stayed at a fixed attitude with respect to the Sun. If it functioned simply as a solar sail the easiest solution would be to eject the sail. If you have to keep it to power your PV array then you would surely be complicating matters.

For which attitude would you want to use? To have the mylar facing the Sun would be best for reflecting light back into PV array. However, doing so would probably have all that mylar acting like a solar sail again, trying to drag the probe in directions its masters back on Earth would (probably) not want it to go in. The latter could be minimised by having the mylar face edge-on with respect to the Sun, but doing that would also minimise the amount of light being reflected into the PV array.

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Stephen
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Greg Hullender
post Jul 25 2006, 05:01 AM
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But surely at the distance of Neptune the force applied by light to a mirror can't amount to much -- especially when the point of the mirror is to collect about as many photons as the solar panels on a Mars probe receive all the time! (Or do Mars probes have a big problem coping with the force of the photons falling on their solar cells?)
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Posts in this topic
- Rob Pinnegar   Neptune Orbiter   Nov 10 2005, 03:51 PM
- - elakdawalla   I don't know much myself about what's poss...   Nov 10 2005, 04:43 PM
|- - tedstryk   I would really like to see a Neptune orbiter with ...   Nov 10 2005, 05:26 PM
|- - Rob Pinnegar   QUOTE (tedstryk @ Nov 10 2005, 11:26 AM)Maybe...   Nov 10 2005, 05:59 PM
|- - elakdawalla   QUOTE (tedstryk @ Nov 10 2005, 10:26 AM)I wou...   Nov 10 2005, 06:20 PM
|- - JRehling   QUOTE (elakdawalla @ Nov 10 2005, 11:20 AM)Ho...   Nov 10 2005, 07:09 PM
||- - tedstryk   If an orbiter is a long way off, I think a Triton ...   Nov 10 2005, 07:13 PM
||- - ljk4-1   QUOTE (tedstryk @ Nov 10 2005, 02:13 PM)If an...   Nov 10 2005, 07:53 PM
||- - Jeff7   QUOTE (tedstryk @ Nov 10 2005, 02:13 PM)If an...   Nov 11 2005, 05:20 PM
|- - hendric   QUOTE (elakdawalla @ Nov 10 2005, 12:20 PM)Ho...   Nov 16 2005, 08:22 AM
|- - Rob Pinnegar   QUOTE (hendric @ Nov 16 2005, 02:22 AM)Accord...   Nov 16 2005, 02:02 PM
|- - tedstryk   It is no doubt battered, but so is Mimas. A possi...   Nov 16 2005, 02:28 PM
|- - Rob Pinnegar   QUOTE (tedstryk @ Nov 16 2005, 08:28 AM)A pos...   Nov 16 2005, 05:09 PM
- - RNeuhaus   The trip to planets beyond than Saturn, I think th...   Nov 10 2005, 07:38 PM
|- - tasp   QUOTE (RNeuhaus @ Nov 10 2005, 01:38 PM)The t...   Nov 10 2005, 09:49 PM
|- - RNeuhaus   QUOTE (tasp @ Nov 10 2005, 04:49 PM)Prometheu...   Nov 10 2005, 10:00 PM
|- - JRehling   QUOTE (tasp @ Nov 10 2005, 02:49 PM)Prometheu...   Nov 10 2005, 10:06 PM
|- - tasp   To revise and extend my remarks, Would a reusable...   Nov 11 2005, 12:59 AM
|- - tasp   Meanwhile, back at Neptune, Has anyone considered...   Nov 11 2005, 01:09 AM
|- - Rob Pinnegar   QUOTE (tasp @ Nov 10 2005, 07:09 PM)Has anyon...   Nov 11 2005, 01:36 AM
|- - tedstryk   QUOTE (Rob Pinnegar @ Nov 11 2005, 01:36 AM)T...   Nov 11 2005, 02:28 AM
|- - Rob Pinnegar   QUOTE (tedstryk @ Nov 10 2005, 08:28 PM)I don...   Nov 11 2005, 06:22 AM
- - Decepticon   There where some ideas for Neptune orbiter in Astr...   Nov 11 2005, 12:42 AM
- - BruceMoomaw   There has actually been quite a lot of work done b...   Nov 11 2005, 04:01 AM
- - tasp   I'll digress to Uranus orbiting briefly. Assu...   Nov 11 2005, 04:11 AM
|- - JRehling   QUOTE (tasp @ Nov 10 2005, 09:11 PM)I'll ...   Nov 11 2005, 02:23 PM
|- - tedstryk   QUOTE (JRehling @ Nov 11 2005, 02:23 PM)Unfor...   Nov 11 2005, 03:01 PM
||- - Rob Pinnegar   QUOTE (tedstryk @ Nov 11 2005, 09:01 AM)That ...   Nov 11 2005, 05:11 PM
|- - tasp   QUOTE (JRehling @ Nov 11 2005, 08:23 AM)If th...   Nov 11 2005, 03:12 PM
|- - JRehling   QUOTE (tasp @ Nov 11 2005, 08:12 AM)Can ...   Nov 11 2005, 04:45 PM
- - BruceMoomaw   I may have something to say on THAT subject in my ...   Nov 11 2005, 04:53 AM
- - BruceMoomaw   That's another reason why, given the likely de...   Nov 11 2005, 10:18 PM
- - tasp   Alex Blackwell has a post in the Uranus Orbiter th...   Nov 12 2005, 02:26 PM
|- - tedstryk   Here is an approach sequence of Proteus. All colo...   Nov 15 2005, 11:59 PM
|- - Rob Pinnegar   QUOTE (tedstryk @ Nov 15 2005, 05:59 PM)It is...   Nov 16 2005, 06:25 AM
- - tasp   And even Miranda is somewhat oblongish. Would I b...   Nov 16 2005, 06:31 PM
|- - David   QUOTE (tasp @ Nov 16 2005, 06:31 PM)And even ...   Nov 17 2005, 03:11 AM
- - tasp   I suspect the 'lumpiness' of Iapetus is a ...   Nov 17 2005, 04:46 AM
|- - Bob Shaw   QUOTE (tasp @ Nov 17 2005, 05:46 AM)I suspect...   Nov 17 2005, 08:01 PM
- - tasp   With a greater understanding or how orbital tours ...   Nov 26 2005, 02:55 PM
- - Decepticon   A simple Google search reveled this!? What P...   Nov 26 2005, 03:41 PM
- - BruceMoomaw   That's the nuclear-electric version of Neptune...   Nov 27 2005, 02:43 AM
- - Decepticon   I hate anything that Unfurls. When Galileo...   Nov 27 2005, 12:31 PM
- - BruceMoomaw   Just keep in mind that Galileo's antenna was e...   Nov 27 2005, 01:32 PM
|- - vjkane2000   QUOTE (BruceMoomaw @ Nov 27 2005, 06:32 AM)Ju...   Nov 28 2005, 03:38 AM
|- - mchan   QUOTE (BruceMoomaw @ Nov 27 2005, 05:32 AM)Ju...   Nov 29 2005, 07:51 AM
- - edstrick   In a conversation some 10? years ago, maybe at the...   Nov 28 2005, 06:06 AM
- - edstrick   Deployments have ALWAYS been one of the big missio...   Nov 29 2005, 08:44 AM
- - tasp   Just in case NASA/JPL finds themselves looking for...   Dec 5 2005, 05:23 AM
- - dvandorn   Does Triton *really* have enough of an atmosphere ...   Dec 5 2005, 07:35 AM
|- - Toma B   QUOTE (dvandorn @ Dec 5 2005, 10:35 AM)Does T...   Dec 5 2005, 08:34 AM
|- - chris   QUOTE (Toma B @ Dec 5 2005, 08:34 AM)Solution...   Dec 5 2005, 10:49 AM
||- - Toma B   QUOTE (chris @ Dec 5 2005, 01:49 PM)Which cou...   Dec 5 2005, 11:42 AM
||- - chris   QUOTE (Toma B @ Dec 5 2005, 11:42 AM)What did...   Dec 5 2005, 12:52 PM
||- - Toma B   QUOTE (chris @ Dec 5 2005, 03:52 PM)If you la...   Dec 5 2005, 01:27 PM
||- - paxdan   QUOTE (Toma B @ Dec 5 2005, 01:27 PM)Question...   Dec 5 2005, 01:47 PM
|||- - ljk4-1   Drop a probe right into one of the Triton geysers....   Dec 5 2005, 02:57 PM
||- - chris   QUOTE (Toma B @ Dec 5 2005, 01:27 PM)Question...   Dec 5 2005, 03:07 PM
||- - Toma B   QUOTE (chris @ Dec 5 2005, 06:07 PM)I wasn...   Dec 6 2005, 08:48 AM
||- - chris   QUOTE (Toma B @ Dec 6 2005, 08:48 AM)All righ...   Dec 6 2005, 10:41 AM
|- - helvick   QUOTE (Toma B @ Dec 5 2005, 09:34 AM)Mars atm...   Dec 5 2005, 12:02 PM
|- - JRehling   QUOTE (Toma B @ Dec 5 2005, 12:34 AM)Mars atm...   Dec 5 2005, 04:23 PM
- - edstrick   Note that the surface of Triton may be very rough ...   Dec 5 2005, 11:07 AM
- - tasp   Check out the last half of the Uranus orbiter thre...   Dec 5 2005, 03:05 PM
- - ermar   As a long-time lurker, sorry for spamming links, b...   Dec 10 2005, 02:23 AM
|- - Toma B   QUOTE (ermar @ Dec 10 2005, 05:23 AM)As a lon...   Dec 10 2005, 06:56 AM
- - BruceMoomaw   They definitely won't fly the nuclear-propelle...   Dec 10 2005, 06:42 AM
- - BruceMoomaw   Sure: http://www.lpi.usra.edu/opag/jun_05_meetin.....   Dec 10 2005, 08:46 AM
|- - tedstryk   QUOTE (BruceMoomaw @ Dec 10 2005, 08:46 AM)Th...   Dec 10 2005, 01:29 PM
- - AlexBlackwell   I apologize for reviving a dead thread; however, F...   Jul 17 2006, 07:51 PM
|- - Rob Pinnegar   QUOTE (AlexBlackwell @ Jul 17 2006, 01:51...   Jul 18 2006, 03:36 PM
|- - JRehling   I would think that at some point the weight of the...   Jul 18 2006, 03:38 PM
|- - Chmee   QUOTE (JRehling @ Jul 18 2006, 11:38 AM) ...   Jul 18 2006, 03:47 PM
|- - AlexBlackwell   QUOTE (Chmee @ Jul 18 2006, 05:47 AM) By ...   Jul 18 2006, 04:42 PM
- - ljk4-1   I wonder if a very large solar sail could be desig...   Jul 18 2006, 05:34 PM
- - Analyst   Before the "nuclear problem" comes the m...   Jul 20 2006, 10:54 AM
|- - antoniseb   QUOTE (Analyst @ Jul 20 2006, 04:54 AM) B...   Jul 21 2006, 11:52 PM
|- - Stephen   QUOTE (antoniseb @ Jul 21 2006, 11:52 PM)...   Jul 25 2006, 04:35 AM
|- - Greg Hullender   But surely at the distance of Neptune the force ap...   Jul 25 2006, 05:01 AM
|- - helvick   QUOTE (Greg Hullender @ Jul 25 2006, 06:0...   Jul 25 2006, 05:34 AM
- - ljk4-1   Would a Neptune orbiter be able to utilize the pla...   Jul 25 2006, 02:58 PM
|- - TritonAntares   QUOTE (ljk4-1 @ Jul 25 2006, 03:58 P...   Jul 25 2006, 11:17 PM
- - qraal   Hi All Solar concentrators are such a cool concep...   Jul 26 2006, 01:40 PM
- - mimile   There have been many good answers to the question ...   Feb 11 2007, 11:38 AM
- - Rob Pinnegar   Those are good points, but it may be worth keeping...   Feb 11 2007, 05:04 PM
- - nprev   Nereid: 27.6 deg with respect to Neptune's equ...   Feb 11 2007, 05:37 PM
|- - JRehling   It's odd that people brought the topic of Nere...   Feb 12 2007, 01:42 AM
- - nprev   Good point, JR. In fact, Nereid spins pretty fast:...   Feb 12 2007, 04:13 AM
- - tasp   OK, I am not smart enough to visualize this in my ...   Feb 12 2007, 06:24 AM
- - mchan   Possibly that the node crossings of the two orbits...   Feb 12 2007, 08:05 AM
- - tasp   Wikipedia has stats on Nereid and reports its...   Feb 12 2007, 03:14 PM
|- - JRehling   QUOTE (tasp @ Feb 12 2007, 07:14 AM) Wiki...   Feb 12 2007, 04:12 PM
- - tasp   Thanx, appreciate the clarification very much. So...   Feb 13 2007, 03:43 AM
- - Rob Pinnegar   The orbits will certainly precess -- but at that d...   Feb 14 2007, 01:57 AM
|- - TritonAntares   Hi, any ideas for an illustration, report, paper, ...   Feb 17 2007, 09:16 PM
|- - TritonAntares   Hi again, here a link to a french website dealing ...   Feb 18 2007, 02:10 PM
|- - tedstryk   It also has some of the strangest seasons, due to ...   Feb 22 2007, 02:13 PM
- - mchan   There is a graph in "The New Solar System...   Feb 17 2007, 11:42 PM
- - Rob Pinnegar   Yeah, looking at some of the references cited abov...   Mar 1 2007, 02:30 PM
- - tasp   Just throwing out some ideas here: Modify a follo...   Mar 2 2007, 05:30 AM
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