Manned mission to Ceres?

PJay_A · Nov 22, 2008

I was just examining the Hubble Ceres images pixel for pixel and I am convinced that we are in for a big surprise when its visited by DAWN in 2015. I'm seeing the following surface features:Mountains with snow and ice on its summitsValleys lined with blue that's either water or iceRiver deltas of either water or iceLakes and/or oceans of water or iceA bluish haze over the entire surface that's either ice or an atmosphereWhere's there's water, there may be life. This may be a less hostile world than Mars with possible life resources, which begs the question: Why not send a manned mission?

3488 · Nov 22, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I was just examining the Hubble Ceres images pixel for pixel and I am convinced that we are in for a big surprise when its visited by DAWN in 2015. I'm seeing the following surface features:Mountains with snow and ice on its summitsValleys lined with blue that's either water or iceRiver deltas of either water or iceLakes and/or oceans of water or iceA bluish haze over the entire surface that's either ice or an atmosphereWhere's there's water, there may be life. This may be a less hostile world than Mars with possible life resources, which begs the question: Why not send a manned mission? Posted by PJay_A</DIV> Hi PJay_A.I think your imagination is running a little wild. Remember the Hubble images of 1 Ceres are enhanced, to make surface features easier to see. 1 Ceres is actually much greyer, with a dark reddish tone, than seen here. 1 Ceres is only approx 940 KM wide & has a surface gravity of approx 2.8% of Earth's.The maximum surface temperature is approx -40 C, global average -110 C & atmosphere, hardly one exists, a very thin envelope of gasses, yes, but far too tenuous to be an atmosphere.True the Hubble images are tantalising, but no snow covered peaks, rivers or oceans I'm afraid. 1 Ceres is a desolate world, but with some interesting potential geology & chemistry to be had for sure & DAWN will show us. I assume you mean this image. <img src="http://sitelife.space.com/ver1.0/Content/images/store/5/1/c5abb819-8402-4d0c-8131-c94c2879acd7.Medium.jpg" alt="" />Also here is a KECK AO image of 1 Ceres, clearly showing craters & smoothish plains.<img src="http://sitelife.space.com/ver1.0/Content/images/store/11/12/8b567804-83c5-4e42-acb9-dd05ee611ea9.Medium.jpg" alt="" />  Andrew Brown.  <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

MarkStanaway · Nov 22, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I was just examining the Hubble Ceres images pixel for pixel and I am convinced that we are in for a big surprise when its visited by DAWN in 2015. I'm seeing the following surface features:Mountains with snow and ice on its summitsValleys lined with blue that's either water or iceRiver deltas of either water or iceLakes and/or oceans of water or iceA bluish haze over the entire surface that's either ice or an atmosphereWhere's there's water, there may be life. This may be a less hostile world than Mars with possible life resources, which begs the question: Why not send a manned mission? Posted by PJay_A</DIV>I assume these are tongue-in-cheek speculations based on the very limited information we have on Ceres.If ony it were true! <div class="Discussion_UserSignature"> </div>

kelvinzero · Nov 22, 2008

I find Ceres a very interesting planet especially from the point of view of humans in space.http://en.wikipedia.org/wiki/Ceres_(dwarf_planet) (This label is missleading. We have no direct evidence of dwarves)The obvious problem is that it would take something like twice as long to get there, compared to Mars. However I feel this makes it a very worthwhile target because a large focus would be on a long term lifesupport. This is an area that I feel is very important to earth, that we can make great strides in, and in fact indefinite lifesupport is entirely plausible.Long term health in low gravity, radiation shielding and some high ISP thrust would also become important. These are also very important for our long term future in space and applicable to many diverse missions.Despite being further, launch windows to ceres are almost twice as frequent as to MarsCeres very probably has vast quantities of ice and other materials that the moon does not have. I expect it to be a resource smorgasboard.Its very low gravity will make landing on it and leaving again much easier than the moon and much MUCH easier than Mars.It has a low axial tilt, so like the moon it may have peaks of eternal light. Although the sun may be 9 times weaker than at the moon and less than half that at mars, the low gravity should make it easy to put some very tall lightweight solar collectors up here.Anyway, it has a night of only about 4.5 hours and probably no dust problem, so this may make solar power much less problematic than either the Moon (2 week night) or Mars (dust storms), anywhere on its surface.Apart from all that I expect it to be a very interesting world in its own right, both because it is not just another Moon or Mars, and also because it may teach us a lot about the many icy worlds in this solarsystem compared to which the Moon and Mars are just oddities.(to the many people on this site who know alot more than just a wiki article, please consider this post a cry for help

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samkent · Nov 24, 2008

While it may have interesting features it doesn’t have anything that we don’t already have down here.  We can’t get long-term life support on the ISS what makes you think we can do it for a mission the Ceres?  Manned mission this century? It won’t happen. Reasons..No reasonNo money

MarkStanaway · Nov 24, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>While it may have interesting features it doesn’t have anything that we don’t already have down here.  We can’t get long-term life support on the ISS what makes you think we can do it for a mission the Ceres?  Manned mission this century? It won’t happen. Reasons..No reasonNo money Posted by samkent</DIV>That's a big call to make from the standpoint of first decade of the twenty first century! Who can predict what priorities and possibilities there will be four generations hence. Making projections based on current socio-economic conditions is fraught with pitfallsMark <div class="Discussion_UserSignature"> </div>

mithridates · Nov 27, 2008

It takes somewhat longer to get to Ceres but at the same time launch windows are far more frequent than to Mars, so the actual time a mission would take to get to Ceres and back would be less than the mission time to and from Mars. Assuming we have the ability to shield humans from the solar radiation for the time it takes to get to Mars, the extra time for the trip to Ceres would be just as possible. At the same time the much lower gravity would make it that much easier to get back in terms of both mass and cost. I'm really looking forward to 2015 because I also think Ceres could turn out to be quite a good location to explore, assuming there are no weird surprises in store.That won't be for quite some time of course; at present after Dawn I would most like to see a rover explore the surface. With a gravity only 5% that of Earth it could probably hop from place to place, and the lack of weather (no sandstorms), and shorter day (10 hours long) and almost complete lack of seasons would make it that much easier to plan for. You're basically dealing with the same thing every day - 5 hours of light, 5 hours of darkness, no weather, no seasons, repeat.  Edit: I wrote this before reading the rest of the thread (exciting topic for me) and I see kelvinzero pretty much wrote the same thing. Good to see we're on the same page. <div class="Discussion_UserSignature"> ----- http://mithridates.blogspot.com </div>

3488 · Nov 27, 2008

I agree mithridates, BTW its great to see you again, 1 Ceres will be a great place to eventually send humans.I think 1 Ceres has huge scarps & cliffs, looking a cross between, Mercury, Dione & Ariel. All have scarps & all have primitive looking surfaces, all have seen geological activity, but have also been quiet more recently.I think with 1 Ceres, my hypothetical scarps would be due to the ice rich crust freezing quickly, but the ice rich mantle froze more slowly. As that froze, it expanded very slightly, causing the already hard brittle frozen crust to crack, possibly compression features & even cryovolcanism. How long ago will depend on how well preserved said features may be. I suspect 1 Ceres is going to be very heavily cratered, given the position within the Asteroid Belt, but hopefully some interesting stuff, if it ever existed has remained uncratered. Since then any surface ice has sublimated, so I suspect the surface of 1 Ceres is ice poor, though underneath ice rich, with perhaps some exposed ice in the shadowed polar craters.DAWN will show us something very interesting IMO at BOTH 4 Vesta & 1 Ceres.Andrew Brown.  <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

mithridates · Nov 28, 2008

Thanks. I haven't really gone anywhere, just been lurking for the past while.Out of curiosity, if you were in charge of exploration to Ceres what would you suggest we do after Dawn assuming we find more or less what we expect to there? Besides sending a rover or two, a sample return mission shouldn't be beyond the realm of possibility considering the low gravity. <div class="Discussion_UserSignature"> ----- http://mithridates.blogspot.com </div>

3488 · Nov 28, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Thanks. I haven't really gone anywhere, just been lurking for the past while.Out of curiosity, if you were in charge of exploration to Ceres what would you suggest we do after Dawn assuming we find more or less what we expect to there? Besides sending a rover or two, a sample return mission shouldn't be beyond the realm of possibility considering the low gravity. Posted by mithridates</DIV>Great question mithridates.Sending a rover or two are musts as are maybe five fixed landers spaced well apart not too unlike Phoenix one each at each pole & three well spaced longitudely at lower latitudes. All equipped with seismometers, TEGA like labs & a SSI camera system similar to Phoenix.The rovers obviously could be modelled on the hugely successful MERs, so I really do not think that we have to reinvent the wheel here. Another lander maybe sent later would certainly be sample return, more likely from one of the polar regions. Something that could burrow would be interesting, though that could be part of the Sample Return mission & could continue well after the actual return capsule has left with a sample. Whether or not I'd send another orbiter, I dunno, perhaps we may need one as a relay. If DAWN succeeds & based on current performance since launch suggests that she will, may not require another orbiter, unless it is very low with an MRO HiRISE type multispectral camera & some sort of ground penetrating radar like SHARAD (shallow) or MARSIS (deep). My answer is certainly in the first instance, is at least one rover, preferably two (one polar, one equatorial) & as many as five fixed identical landers (all clones like the two Vikings or the seven Pre Apollo Lunar Surveyor Landers of which five were a resounding success), to increase the surface science coverage from five very different sites (panoramas, multispectral remote sensing, on board lab analysis & seismological data). Andrew Brown.  <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

JonClarke · Nov 28, 2008

It might not be that interesting Andrew! <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-laughing.gif" border="0" alt="Laughing" title="Laughing" /> <div class="Discussion_UserSignature"> Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars Arthur Clarke </div>

3488 · Nov 28, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>It might not be that interesting Andrew! Posted by jonclarke</DIV>Indeed, may not be as interesting as we think Jon, I only based my ideas on current info & ideas. Seven landers for such a small body does seem overkill, considering we have had only six successes on Mars, given how varied Mars is, a handful on Venus (almost as large as Earth with interesting geology), none as yet on Mercury (fascinating small planet, more varied than we thought after Mariner 10) & the Jupiter Galileans (very varied indeed from active volcanoes to impact craters).1 Ceres though IMO is still worthy of at least two, maybe one rover & one fixed geophysical lander. DAWN will certainly tell us if 1 Ceres is worth follow ups or not. I suspect the answer will still be yes. We'll see in time.Andrew Brown.  <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

silylene · Nov 28, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Indeed, may not be as interesting as we think Jon, I only based my ideas on current info & ideas. Seven landers for such a small body does seem overkill, considering we have had only six successes on Mars, given how varied Mars is, a handful on Venus (almost as large as Earth with interesting geology), none as yet on Mercury (fascinating small planet, more varied than we thought after Mariner 10) & the Jupiter Galileans (very varied indeed from active volcanoes to impact craters).1 Ceres though IMO is still worthy of at least two, maybe one rover & one fixed geophysical lander. DAWN will certainly tell us if 1 Ceres is worth follow ups or not. I suspect the answer will still be yes. We'll see in time.Andrew Brown.  Posted by 3488</DIV> The escape velocity on Ceres is just 0.68 km/sec.  By comparison, the Moon is 2.38 km/sec, and Mars is 5.03 km/sec. Andrew, I disagree with your missions choices.  Ceres definately merits a sample-return mission, perhaps on the first lander !  If nothing else, this would be a good practice for a future manned landing  (and I think there would be a lot of good science from a sample return mission too.) <div class="Discussion_UserSignature"> petet = silylenePlease, please give me my handle back ! </div>

JonClarke · Nov 28, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>The escape velocity on Ceres is just 0.68 km/sec.  By comparison, the Moon is 2.38 km/sec, and Mars is 5.03 km/sec. Andrew, I disagree with your missions choices.  Ceres definately merits a sample-return mission, perhaps on the first lander !  If nothing else, this would be a good practice for a future manned landing  (and I think there would be a lot of good science from a sample return mission too.) Posted by petet</DIV>As the main interest in Ceres is likley to be geochemical, a small sample return mission might indeed be the most valuable.  Comparisons between the differentiated hydrated rocks of Ceres with the dry differentiated rocks of Vesta would be most instructive.Fully autonomous sample collection,loading and docking should be developed by for Mars sample return, and a very small ascent vehicle would be enough to launch the sample container into orbit for rendezvous with an ion powered sample return craft. No planetary protection would be needed either, making handling a since compared to Mars. The orbital velocity of Ceres surely can't be much more than 500 m/s?  Maybe samples could be returned from several sites?Jon <div class="Discussion_UserSignature"> Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars Arthur Clarke </div>

silylene · Nov 30, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>As the main interest in Ceres is likley to be geochemical, a small sample return mission might indeed be the most valuable.  Comparisons between the differentiated hydrated rocks of Ceres with the dry differentiated rocks of Vesta would be most instructive.Fully autonomous sample collection,loading and docking should be developed by for Mars sample return, and a very small ascent vehicle would be enough to launch the sample container into orbit for rendezvous with an ion powered sample return craft. No planetary protection would be needed either, making handling a since compared to Mars. The orbital velocity of Ceres surely can't be much more than 500 m/s?  Maybe samples could be returned from several sites?Jon Posted by jonclarke</DIV>Whew!  I am glad I can finally see your response, after you got restored back into the Pluck-verse, Jon and Andrew, it seems we are coalescing around a good plan for a Ceres mission - an unmanned sample return mission.  Jon, you make a very interesting point about the feasibility of multiple landings and samplings.  I do think this should be a priority.  If NASA cannot do it, perhaps ESA, the Russians , the Japanese or even India might be interested? <div class="Discussion_UserSignature"> petet = silylenePlease, please give me my handle back ! </div>

JonClarke · Nov 30, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Whew!  I am glad I can finally see your response, after you got restored back into the Pluck-verse,Jon and Andrew, it seems we are coalescing around a good plan for a Ceres mission - an unmanned sample return mission.  Jon, you make a very interesting point about the feasibility of multiple landings and samplings.  I do think this should be a priority.  If NASA cannot do it, perhaps ESA, the Russians , the Japanese or even India might be interested? Posted by petet</DIV>It is good to be incarnate again!Ceres Sample Return  would be a big, complex mission,  so almost certainly an international consortium would be the way to do.  I don't think it would even begin to be planned for until we see the results of Dawn.By then we should know more about the surface and how variable it is, and how maany landing sites would be needed.  By then to MSR should be well advanced and we should know much more about such complex missions.  the experience of Phobos Grunt and Hayabusa would have been well digested too. <div class="Discussion_UserSignature"> Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars Arthur Clarke </div>

efron_24 · Dec 1, 2008

to even think about Ceres is a waste of many thingswe need to focus only a few things this centuryMoon.. as stepping stoneMars.. as new EarthEnceladus as possible place where life might be Titan.. because it is a deepfreeze earth and it was discovered by one of the most important man in history <div class="Discussion_UserSignature"> </div>

mithridates · Dec 1, 2008

There's another much easier destination as well to search for life: the cloudtops of Venus.http://www.universetoday.com/2008/07/25/if-life-exists-on-venus-could-it-be-blown-to-earth/Ceres isn't a waste though, for all the reasons given above. <div class="Discussion_UserSignature"> ----- http://mithridates.blogspot.com </div>

silylene old · Dec 1, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>to even think about Ceres is a waste of many thingswe need to focus only a few things this centuryMoon.. as stepping stoneMars.. as new EarthEnceladus as possible place where life might be Titan.. because it is a deepfreeze earth and it was discovered by one of the most important man in history Posted by efron_24</DIV> OK, let me go down the list of 'challenges' for doing an unmanned sampling return mission:Mars requires a heavy heatshield, and a sample return mission is difficult given the high required escape velocity (5.02 km/sec).  A return mission requires carrying a lot of fuel instead of science instruments or many samples..  The high surface gravity means that the lander can only sample one location.  EXPENSIVE!Titan requires a heavy heatshield, and a sample return mission is difficult given the extreme distance from Earth and high required escape velocity (2.65 km/sec), and in addition, the craft also would have to pull itself out of the Saturn gravity well.   A return mission requires carrying a lot of fuel instead of science instruments or many samples.  This makes a sampling return mission very difficult.  Power supply in the thick dark atmosphere would require an expensive and heavy nuclear source, which means less weight for instruments, and solving heat management issues so the craft doesnt sink into the thawing soils.  An orbiter would also be required for communication  (more expensive).  On the positive side, perhaps a balloon could be used to move the craft around to sample different locations.  EXPENSIVE!Enceladus mission would require a large amount of fuel to decelerate in the Saturnian gravity well and get captured by this tiny moon, and then another large amount of fuel to escape from Saturn's gravity well and get back to earth.  On the positive side, at least the Enceladus escape velocity is low (0.24 km/s), so perhaps the craft could be lifted and re-landed at different areas for multiple sampling sites.  Power supply in the distance from earth would require an expensive and heavy nuclear source, which means less weight for instruments, and solving heat management issues so the craft doesnt sink into the thawing ices.  An orbiter would also be required for communication  (more expensive).  EXPENSIVE!A mission to Ceres would be much easier, given is close proximity, and its tiny gravity (escape velocity = 0.53 km/sec).  This means much less fuel is required to land and return.  The tiny gravity would allow the craft to hop and reland at different locations for multiple sampling.  Also no expensive and heavy nuclear fuel supply is needed. No heat shield would be needed.  All told, much more mass could be devoted to instruments.  In many ways, Ceres is ideal for an unmanned sample return mission.  COMPARTIVELY CHEAP! <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center">- - - - - - - - - - - - - - - - - - - - - - </div><div class="Discussion_UserSignature" align="center">I really, really, really miss the "first unread post" function. </div> </div>

JonClarke · Dec 1, 2008

Another advantage of Ceres is that any regolith sample would contain a rocks of mixed provenance.  A simple rake would collect a range of these sufficient for a representative sample from many locations..  This idea was first used on Apoll 15 and developed for unmaned LSR missions.  It won't work on Titan or Mars or Venus, but definitely on Ceres.But first we need to know what we are looking at.  So this is a project for the 2020's <div class="Discussion_UserSignature"> Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars Arthur Clarke </div>

3488 · Dec 1, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Whew!  I am glad I can finally see your response, after you got restored back into the Pluck-verse,Jon and Andrew, it seems we are coalescing around a good plan for a Ceres mission - an unmanned sample return mission.  Jon, you make a very interesting point about the feasibility of multiple landings and samplings.  I do think this should be a priority.  If NASA cannot do it, perhaps ESA, the Russians , the Japanese or even India might be interested? Posted by petet</DIV>Hi Silylene,I would be very interestred in being a part of the mission. I know that we will have to wait till DAWN has arrived in Ceres orbit first, but yes, there's no reason why perhaps between the few of us, we can't bounce some ideas around now.I see your point about sample return straight off withut using earlier landers first. The reason why I suggested a multipronged approach was to get a general  picture of the dwarf planet from several locations using siesmometers, cameras & on board TEGA like labs, etc first, thus building up a knowledge base to properly target a sample return & provide a context for said sample return.Mind you  I suppose a sample return lander could do much of that anyway on it's own. Land, photograph the surroundings, deploy seismometer, then begin extracting the samples & loading them onboard. Sample return blast's off & perhaps the portion left behind could carry on seismological, multispectral & photgraphic studies of the landing site, till it fails, thus by the time the sample gets to Earth, we'll already know quite a lot about the site from where it was taken.Also dependent on DAWN data, where  do you think a sample return would be more effective? Polar region, equatorial?Polar regions may contain frost deposits in shadowed areas, but an equatorial site wouild probably be more representative of 1 Ceres as a whole. Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

silylene · Dec 1, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>........Also dependent on DAWN data, where  do you think a sample return would be more effective? Polar region, equatorial?Polar regions may contain frost deposits in shadowed areas, but an equatorial site wouild probably be more representative of 1 Ceres as a whole. Andrew Brown. Posted by 3488</DIV> Jon, I agree this would have to wait for the DAWN data, and planning and everything would push this mission to about perhaps 2017-2020.  Ahh, but it would be a great mission!  3488, I don't know yet, I am eagerly awaiting DAWN data.  If we can launch and re-land three times, a few hundred kms apart, I think we will have the chance to study some widely varied terrain in close detail.  Jon makes the great point that the regolith samples should be rather mixed, anyways. <div class="Discussion_UserSignature"> petet = silylenePlease, please give me my handle back ! </div>

JonClarke · Dec 1, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'> Jon, I agree this would have to wait for the DAWN data, and planning and everything would push this mission to about perhaps 2017-2020.  Ahh, but it would be a great mission!  3488, I don't know yet, I am eagerly awaiting DAWN data.  If we can launch and re-land three times, a few hundred kms apart, I think we will have the chance to study some widely varied terrain in close detail.  Jon makes the great point that the regolith samples should be rather mixed, anyways. Posted by petet</DIV> A hopper that sampled different sites might be easier than seveal landers? <div class="Discussion_UserSignature"> Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars Arthur Clarke </div>

kelvinzero · Dec 4, 2008

Would it be practical or useful to impact something into the surface and then sample material exposed by the impact?Im also interested to see what you come up with to perform this mission. To return a sample from the surface to a craft in orbit you only need 320-500 m/s. You could even use a spudgun. The record for a spudgun is about 900m/s. I checked

(edit)But seriously, perhaps rovers and a fixed ascent vehicle would have real advantages over a single vehicle.<ul><li>Having a craft in orbit allows uninterupted communication to the ground vehicle as well as the advantages of the apollo luna rendezvous. Assuming a craft in orbit affects the next point.</li><li>I did some rough maths and got a figure of about 80m/s velocity at the equator. That could be a worthwhile bonus for launching from the equator. After all the velocity you need to achieve isnt even escape velocity, but orbital velocity to dock with the ion powered return vehicle. In any case if you are docking, then you want a suitable orbit. So maybe your mission will not leave you a reasonable choice of where to ascend from.</li><li>I found this among Dawn's goals: "Obtain a topographic map of 80% of the surface of Ceres, with a horizontal resolution 200m and a vertical resolution 20m." I think with a solar powered rover on the low gravity, low dust environment of Ceres we have the oportunity to examine a staggering volume of surface area up as close as we wish. Compare with mars or the moon where decades later there are still places we would love to see up close but cannot without a specific mission. Why shouldnt there be features on Ceres as rare as caves on earth?</li><li>It would sure be a pity to try for one more sample and end up damaging your hopper if it is also your launch vehicle. If you lose a rover then you will still have whatever samples you collected early on. It is quite reasonable to extend the mission until the rovers fail, or launch and return while the rovers continue.</li><li>If we do put up with the complexity of rovers that have to return to a launch site at the equator, then at least we can also leave any tests we chose to do before returning at the same launch site. This simplifies the rovers and these tests are another consolation should the return fail.</li></ul>

h2ouniverse · Dec 5, 2008

hi all,Well Andrew, you know my position on the matter. I do believe Ceres is going to be one of the top destination because of "follow the water" (or at least "follow the water ice"). And I think some water ice will be permanently exposed close to the poles (and not only in ever shadowed areas), where temperatures never exceed 130 or 150K. Contrary to "ice on the moon" or "ice on mercury" the ice there would be indigenous and would not depend on overstretched scenarii such as a comet bringing it and crashing precisely in an evershadowed area. Also, spin axis orientations may vary with time (and that is the issue with our Moon). In the case of Ceres, if H2O is endogenic, it will tend to form frost plates wherever it can, even if the tilt varies.Ceres should be, imho, an icy body like the ones of the outer system, covered with regolith (beneath frost line). But the Frost line is a valid notion at equator, not at poles.I would privilege a Phoenix-like Lander in the polar areas. A Rover will be too heavy to bring at a reasonable cost unless we progress significantly on miniaturisation (but then, which science would it be able to accomplish?).A Sample Return will be extremely expensive, far more than Phobos-Grunt or Marco Polo because the gravity, although low, is not negligible => you need soft landing techniques, not rendezvous techniques like on Phobos or an asteroid. best regards.

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