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Uranus Orbiter, The other proposed ice-giant mission
Rob Pinnegar
post Nov 11 2005, 05:13 PM
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Since the Neptune Orbiter thread has started to veer into talking about a Uranus orbiter as well, it seemed like a good idea to start a topic for Uranus.
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tasp
post Nov 15 2005, 06:16 PM
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Without incurring copyright snags, of course, could I field a question about the ideas in the paper?

The portion available through the link ends with an intriguiging acknowledgement that the vehicle could enter orbit about Ariel after ~40 loops around Uranus.

Is this characteristic of the orbit tour similar (at least broadly) to the clever trajectory Messenger is utilizing to eventually end up in orbit about Mercury?

I realize the mass ratios of Sun - Mercury - Venus - Earth are quite different, but is there a correlation between the flight plans?

Amazing article, regardless!
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Guest_AlexBlackwell_*
post Nov 15 2005, 06:34 PM
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QUOTE (tasp @ Nov 15 2005, 06:16 PM)
Without incurring copyright snags, of course, could I field a question about the ideas in the paper?

The portion available through the link ends with an intriguiging acknowledgement that the vehicle could enter orbit about Ariel after ~40 loops around Uranus.

Is this characteristic of the orbit tour similar (at least broadly) to  the clever  trajectory Messenger is utilizing to eventually end up in orbit about Mercury?

I realize the mass ratios of Sun - Mercury - Venus - Earth are quite different, but is there a correlation between the flight plans?

Amazing article, regardless!
*

Darn, wouldn't you know that I don't have a copy of the paper available on my system at the moment biggrin.gif

That said, I'll review it when I get home but from what I recall, the main concept behind the end-of-tour plan to insert into orbit at Ariel is based on orbital pumping and cranking, which not only changes inclination from the initial Uranian insertion, but reduces relative velocity so that the deterministic delta-V for insertion at Ariel can be handled by the orbiter's propulsion system. I can't remember whether the scheme also utilizes any "third-body" effects from Uranus or "fuzzy boundaries" but these might possible as was planned for the original Europa Orbiter insertion in europan orbit.

Whether this resembles, even in a broad sense, the MESSENGER trajectory through the inner solar system, is, I guess, in the eye of the beholder.
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tasp
post Nov 26 2005, 02:27 PM
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QUOTE (AlexBlackwell @ Nov 15 2005, 12:34 PM)
Darn, wouldn't you know that I don't have a copy of the paper available on my system at the moment  biggrin.gif

That said, I'll review it when I get home but from what I recall, the main concept behind the end-of-tour plan to insert into orbit at Ariel is based on orbital pumping and cranking, which not only changes inclination from the initial Uranian insertion, but reduces relative velocity so that the deterministic delta-V for insertion at Ariel can be handled by the orbiter's propulsion system.  I can't remember whether the scheme also utilizes any "third-body" effects from Uranus or "fuzzy boundaries" but these might possible as was planned for the original Europa Orbiter insertion in europan orbit.

Whether this resembles, even in a broad sense, the MESSENGER trajectory through the inner solar system, is, I guess, in the eye of the beholder.
*


Have reviewed the Heaton/Longuski paper (Thanx!) now and have some comments.

The 'clever bit' of the Messenger trajectory, gravitational interaction with the target object to facilitate orbital insertion, isn't employed at Ariel. This technique is not addressed in the paper, but since utilizing it would take quite a while (if it were even possible at Ariel) and the paper was assuming 2 year long orbital missions the omission is not surprising. Also, the 1km/sec 'burn off' at Ariel doesn't seem excessive anyhow, so the utility of the technique at Ariel is less appparent. That the technique works at Mercury may be due more to Mercury's high density alowing the craft to approach closer to the planets center of mass to 'realize the math' than may be possible with an icy body like Ariel. It is not clear (to me) how the mass ratios and distances scale for this technique from sun/Mercury to Uranus/Ariel.

I am also amazed with the Heaton/Longuski trajectory in that in 2 years, 40 (!) encounters with Oberon, Titania, Umbriel, and Ariel are possible. A significant truth revealed in the paper is that since the Uranian system is 'scaled' smaller than the Galilean satelllites, useful distant flybys of Uranian moons also occur more frequently than they did for the Galileo spacecraft.

Inferring to Cassini, it seems the mass ratio of Saturn/Titan being so different from that of Jupiter or Uranus does allow Cassini much more flexibility in changing it's inclination around Saturn. I had wondered why this was not done with Galileo at Jupiter, and it seems many more satellite flybys would be required for a given inclination change than for Cassini at Saturn.

It does seem that an interesting mission could be orbited at Neptune following the Cassini style tour.

Also, granted the enormous delta vee needed to effect orbit insertion around Pluto, once that is achieved, an interesting mission at Pluto is possible utilizing Charons gravity for orbit shaping. Close observations of Pluto and Charon at a variety of inclinations seems quite feasible, and arbitrarily close approaches to the 2 new satellites seems 'easy' now. The big problem remains though, the difficulty in achieving orbit around Pluto due to the high approach speed of any reasonable spacecraft.
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Posts in this topic
- Rob Pinnegar   Uranus Orbiter   Nov 11 2005, 05:13 PM
- - tasp   QUOTE (Rob Pinnegar @ Nov 11 2005, 11:13 AM)S...   Nov 11 2005, 05:46 PM
- - tasp   I admit a keen interest in Uranus. The mass ratio...   Nov 11 2005, 06:08 PM
|- - Rob Pinnegar   QUOTE (tasp @ Nov 11 2005, 12:08 PM)Would Hub...   Nov 11 2005, 07:15 PM
|- - AlexBlackwell   QUOTE (Rob Pinnegar @ Nov 11 2005, 07:15 PM)T...   Nov 11 2005, 07:59 PM
|- - tasp   QUOTE (AlexBlackwell @ Nov 11 2005, 01:59 PM)...   Nov 12 2005, 02:21 PM
|- - AlexBlackwell   QUOTE (tasp @ Nov 12 2005, 02:21 PM)I'll ...   Nov 15 2005, 06:15 PM
|- - tasp   {In re the 20 year mission life at Uranus} I real...   Nov 15 2005, 07:29 PM
- - Rob Pinnegar   Yeah, thanks Alex -- that link was a good read. Ve...   Nov 13 2005, 01:49 AM
|- - AlexBlackwell   QUOTE (Rob Pinnegar @ Nov 13 2005, 01:49 AM)Y...   Nov 15 2005, 06:01 PM
|- - hendric   QUOTE (AlexBlackwell @ Nov 15 2005, 12:01 PM)...   Nov 16 2005, 08:54 AM
|- - AlexBlackwell   QUOTE (hendric @ Nov 16 2005, 08:54 AM)For ...   Nov 16 2005, 05:56 PM
|- - tasp   QUOTE (AlexBlackwell @ Nov 16 2005, 11:56 AM)...   Nov 16 2005, 06:19 PM
|- - AlexBlackwell   QUOTE (tasp @ Nov 16 2005, 06:19 PM)I confess...   Nov 23 2005, 01:49 AM
- - tasp   Without incurring copyright snags, of course, coul...   Nov 15 2005, 06:16 PM
|- - AlexBlackwell   QUOTE (tasp @ Nov 15 2005, 06:16 PM)Without i...   Nov 15 2005, 06:34 PM
|- - tasp   QUOTE (AlexBlackwell @ Nov 15 2005, 12:34 PM)...   Nov 26 2005, 02:27 PM
- - BruceMoomaw   Orbiting Ariel would be a remarkable ending to thi...   Nov 15 2005, 07:31 PM
|- - Bob Shaw   A long time ago (the early 1970s!), I suggeste...   Nov 15 2005, 10:13 PM
- - BruceMoomaw   Well, shucks, how can anybody not jump at a bargai...   Nov 16 2005, 09:23 AM
- - BruceMoomaw   The best way to orbit -- or land on -- either Plut...   Nov 26 2005, 09:23 PM
|- - tasp   QUOTE (BruceMoomaw @ Nov 26 2005, 03:23 PM)Th...   Nov 27 2005, 01:15 AM
- - BruceMoomaw   McRonald's best paper on the subject seems to ...   Nov 27 2005, 03:17 AM
|- - tasp   QUOTE (BruceMoomaw @ Nov 26 2005, 09:17 PM)Mc...   Nov 27 2005, 03:58 AM
- - BruceMoomaw   Just keep in mind that -- because Pluto's grav...   Nov 27 2005, 10:00 AM
|- - tasp   QUOTE (BruceMoomaw @ Nov 27 2005, 04:00 AM)Ju...   Nov 28 2005, 04:45 AM
- - dvandorn   The biggest problem with using steerable aerocaptu...   Nov 29 2005, 02:32 PM
|- - tasp   QUOTE (dvandorn @ Nov 29 2005, 08:32 AM)Like ...   Nov 29 2005, 03:38 PM
- - centsworth_II   What about a small,simple atmospheric probe that w...   Nov 29 2005, 05:49 PM
- - BruceMoomaw   You don't need to grasp at straws -- Tasp...   Nov 29 2005, 09:23 PM
- - BruceMoomaw   The document for simulation tests for a Neptune or...   Nov 30 2005, 08:29 AM
|- - tasp   QUOTE (BruceMoomaw @ Nov 30 2005, 02:29 AM)Th...   Nov 30 2005, 04:36 PM
|- - vexgizmo   An excuse to post in the oh-so-obscure Uranus Orbi...   Feb 2 2006, 07:46 AM
|- - JRehling   QUOTE (tasp @ Nov 30 2005, 08:36 AM)Weird it ...   Feb 2 2006, 05:30 PM
- - PhilHorzempa   Time to re-start this thread. Thanks to Cassini, ...   Apr 9 2007, 05:07 PM
|- - JRehling   QUOTE (PhilHorzempa @ Apr 9 2007, 10:07 A...   Apr 10 2007, 03:02 PM
- - Cugel   Let's not forget that at Neptune Triton would ...   Apr 9 2007, 06:33 PM
|- - PhilHorzempa   QUOTE (Cugel @ Apr 9 2007, 02:33 PM) Let...   Apr 9 2007, 08:52 PM
- - Cugel   I stand corrected. I just wasn't following thi...   Apr 10 2007, 12:12 AM
- - Greg Hullender   Apparently the big reason to prefer Neptune to Ura...   Apr 10 2007, 12:53 AM
- - dvandorn   The other attraction of Triton is, of course, that...   Apr 10 2007, 03:22 PM
|- - JRehling   QUOTE (dvandorn @ Apr 10 2007, 08:22 AM) ...   Apr 10 2007, 05:37 PM
|- - hendric   QUOTE (JRehling @ Apr 10 2007, 12:37 PM) ...   Apr 10 2007, 09:10 PM
- - Rob Pinnegar   A couple of random thoughts in favour of Neptune o...   Apr 11 2007, 03:28 PM
|- - David   QUOTE (Rob Pinnegar @ Apr 11 2007, 03:28 ...   Apr 25 2007, 01:28 AM
- - jsheff   Don't forget that both of them have ring syste...   Apr 21 2007, 08:42 PM
- - Jyril   And don't forget Neptune's second largest ...   Apr 22 2007, 05:08 PM
- - Spirit   What about building two identical probes and launc...   Sep 22 2007, 11:45 AM
|- - infocat13   QUOTE (Spirit @ Sep 22 2007, 07:45 AM) Wh...   Sep 24 2007, 10:45 PM
|- - AscendingNode   QUOTE (infocat13 @ Sep 24 2007, 03:45 PM)...   Sep 25 2007, 12:12 AM
|- - JRehling   QUOTE (infocat13 @ Sep 24 2007, 03:45 PM)...   Sep 25 2007, 05:03 AM
- - djellison   Sounds great! You paying? Seriously - that...   Sep 22 2007, 12:12 PM
|- - JRehling   QUOTE (djellison @ Sep 22 2007, 05:12 AM)...   Sep 22 2007, 06:14 PM
|- - AscendingNode   QUOTE (JRehling @ Sep 22 2007, 11:14 AM) ...   Sep 23 2007, 05:18 AM
|- - JRehling   QUOTE (AscendingNode @ Sep 22 2007, 10:18...   Sep 23 2007, 05:56 AM
|- - ugordan   Regarding attitude-control propellant (i.e. monopr...   Sep 23 2007, 10:41 AM
|- - AscendingNode   QUOTE (JRehling @ Sep 22 2007, 10:56 PM) ...   Sep 23 2007, 02:25 PM
|- - ugordan   QUOTE (AscendingNode @ Sep 23 2007, 04:25...   Sep 23 2007, 03:00 PM
|- - JRehling   QUOTE (AscendingNode @ Sep 23 2007, 07:25...   Sep 23 2007, 09:07 PM
- - brellis   A mothership with a bunch of micro-landers would b...   Sep 22 2007, 04:37 PM
- - djellison   Whilst orbital mechanics dictate that sending Cass...   Sep 23 2007, 05:21 PM
- - tasp   I admit a burning desire for a Uranian orbiter (he...   Sep 23 2007, 05:48 PM
- - djellison   I think Neptune and Uranus orbiters are going to r...   Sep 23 2007, 06:11 PM
- - mchan   Will RTG power levels be sufficient to operate all...   Sep 23 2007, 09:09 PM
|- - tedstryk   Well, 42 years, really. That's how long till ...   Sep 24 2007, 10:11 AM
|- - ugordan   QUOTE (tedstryk @ Sep 24 2007, 12:11 PM) ...   Sep 24 2007, 11:05 AM
- - tasp   The Galileo style tour of the Uranian system is qu...   Sep 24 2007, 12:51 PM
|- - djellison   QUOTE (tasp @ Sep 24 2007, 01:51 PM) A Ur...   Sep 24 2007, 01:52 PM
||- - AscendingNode   QUOTE (djellison @ Sep 24 2007, 06:52 AM)...   Sep 24 2007, 05:34 PM
||- - djellison   QUOTE (AscendingNode @ Sep 24 2007, 06:34...   Sep 24 2007, 05:49 PM
|- - JRehling   I think one difficulty owing to the no-big-moon si...   Sep 24 2007, 03:41 PM
|- - dvandorn   QUOTE (JRehling @ Sep 24 2007, 10:41 AM) ...   Sep 24 2007, 04:32 PM
|- - AscendingNode   QUOTE (JRehling @ Sep 24 2007, 08:41 AM) ...   Sep 24 2007, 05:37 PM
|- - JRehling   Another consideration, a happy one, is that for th...   Sep 25 2007, 02:46 PM
- - djellison   The paper cited above actually discusses the plane...   Sep 24 2007, 03:46 PM
- - nprev   Infocat, I and others on the board have had variat...   Sep 25 2007, 01:00 AM
- - brellis   QUOTE requirements for planetary missions tend to ...   Sep 25 2007, 01:30 AM
|- - nprev   QUOTE (brellis @ Sep 24 2007, 06:30 PM) I...   Sep 25 2007, 03:40 AM
|- - dvandorn   QUOTE (nprev @ Sep 24 2007, 10:40 PM) ......   Sep 25 2007, 05:42 AM
|- - brellis   QUOTE (nprev @ Sep 24 2007, 08:40 PM) Can...   Sep 25 2007, 08:42 AM
- - tasp   Yeah, the Longuski paper describes a mission phase...   Sep 25 2007, 02:19 AM
- - dvandorn   Anyone have any charts handy telling us when we ha...   Sep 25 2007, 05:51 AM
- - mchan   To a first order, there can be Jupiter gravity ass...   Sep 25 2007, 07:30 AM
- - Spirit   Maybe we'll have another opportunity to flyby ...   Sep 25 2007, 04:23 PM
|- - JRehling   QUOTE (Spirit @ Sep 25 2007, 09:23 AM) Ma...   Sep 25 2007, 06:06 PM
- - algorimancer   Perhaps slightly off-topic, but there have been se...   Sep 25 2007, 07:45 PM
- - tedstryk   QUOTE (algorimancer @ Sep 25 2007, 07:45 ...   Sep 25 2007, 09:08 PM
- - algorimancer   QUOTE (tedstryk @ Sep 25 2007, 04:08 PM) ...   Sep 26 2007, 12:37 PM


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