This thread will cover all final phases of the Dawn mission, the end of which is not certain at this point.

XMO3 was suppose to be the final orbit, but now plans have changed and it will move into a new higher altitude and higher phase orbit soon. This will be XMO4.

An interesting monthly journal for January details the plan:

Dawn Journal 31 January 2017

Ahuna mons have turned out to be what is called one "ice volcano"
(Used in lack of a better word in american English I guess, my native language got a word for underground water that instantly freeze as it enter the surface in the wínter which would have been very suitable here.)
Now why only a single such feature?
The American Geophysical Union put some thought on that matter and suspect there's other ones that have flattened out and started a search for potential other sites.

Another possible answer might be that the whole of Ceres is acting like a single pressure vessel with relatively fluid contents. This would require only a single relief valve (at any given time).

Perhaps the raised area adjacent to Ahuna is such a feature:

Click to view attachment

The elevation of this area seems to be anomalous compared to the surrounding topography. It does not appear to be associated with any crater/ basin rims or central peaks. Its association with Ahuna seems to imply a relationship of some kind. The surface of this feature is heavily cratered, which means it has been around much longer than Ahuna. Either this feature is an area of general uplift associated with the formation of Ahuna, or it is an older volcanic edifice of the upwelling that produced Ahuna (i.e. 'ancestral Ahuna') that has subsequently suffered subsidence and erosion. Or perhaps both processes were in play. Finally, it is possible it presence there could be purely coincidental.

@Gladstoner: You might indeed have pointed out Ahuna mons predecessor there.
But yes, it cannot be ruled out that it's associated with the current formation. We just have to wait for the verdict by the professionals.
Regardless of which two it turn out to be, I don't think it's coincidental.

What is interesting is the comparatively short timeframe for a feature like this to relax and get near invisible.
If it is lets say 10 MY, that would mean that there's some ongoing activity inside Ceres to create a feature like Ahuna mons.
The big question then will be if it's continuous or periodical.

Well this higher altitude orbit might perhaps get us a chance to catch an image of the possible fog over Occator. Backlit by the Sun would be the best way to catch it just as on Enceladus.

Based on the features' appearances and on the (apparent) lack of extensive activity on Ceres, I'd think any volcanic processes would be episodic.

" Asteroid Dust Cloaks True Composition Of Dwarf Planet Ceres "

" Observations of Ceres indicate that asteroids might be camouflaged "
http://www.seti.org/seti-institute/press-r...-be-camouflaged

" Dwarf planet Ceres camouflage by asteroid dust ":
http://www.space.com/35451-dwarf-planet-ce...eroid-dust.html

?
Is expected to map temperatures of Ceres? I expected Already for long time :-/

on today's Science (and behind the paywall... )

Localized aliphatic organic material on the surface of Ceres



see also the Science perspective article: Dwarf planet Ceres and the ingredients of life
and the JPL press release: Dawn Discovers Evidence for Organic Material on Ceres

This is the kind of news that could have me literally jumping up and down.
Water, ammonia, salts, cabonates and now this!
It might be quite premature to speculate if any space agency will jump at this opportunity.
But it's a fact that Ceres would provide an easy target for a lander mission.
With the very low gravity it would even be possible to have a 'jumping' lander visiting several sites for sampling.
Even the idea of returning samples might be considered.
Aliphatic organic matter - it's not any of the lighter ones, they would be long gone, from a single spectral line it's hard to say how complex those molecules are.
But I'd give an arm and a leg to have closer look at a sample here on Earth.

There's probably already samples of Ceres on Earth, just not yet identified as such. All those craters must have made sprayed ejecta everywhere and some meteorites must be here now, just by probability.
Otherwise a sample return mission might in fact be easier than Mars; lack of atmosphere and low gravity making up for the greater difference in orbits...

Doesn't atmosphere help you at Mars? You'd need a heck of a lot of fuel to brake from orbit and land without atmospheric drag. The drag would affect a launch from the surface, but with low launch speeds and thin atmosphere I'm guessing that's not a big effect.

Of course lower gravity at Ceres means lack of atmosphere won't be as important as it would've been at Mars.

Yes, I was talking about launching from the surface. I vaguely recall reading an article a few years ago about someone working on an engine for an ascent stage to get straight to Earth, no need for rendezvous; can't find it now. Anyway, this is a discussion for another thread, another time.

Repropose my UP question... ?

I know that Ceres has no seasons like earth. However, we can say that it is entering its warm period. Dawn was arrived to Ceres in the beginning of the cold season. Too bad the mission will end before the maximun warm season of Ceres.

They're starting to publish XMO3 images on the NASA Photojournal! The first is this interesting context view of Ahuna Mons and Occator crater, taken on 11 February.

EDIT: Here's a version I uploaded to Wikimedia Commons, with annotations labelling all the discernible features in the image, per the official nomenclature by the IAU.

Some pictures showing temperature have been generated. Here's a few that I am not sure if have been posted to the Photojournal, where you can find the others. Don't know about global or other larger maps, or time series of temperature.

Thanks!
235 K -38°C
196 K -76°C
However, the VIR images are of the last year.
Ceres from this year begins to warm. The mission will not arrive to the maximum hot season of Ceres, but it could show more high temperatures in the next months....

ADMIN MODE: Moved four recent posts to the former "Water Vapor on Ceres" thread, which has been retitled "Ceres Geology". I think that discussion will continue long after the Dawn mission is completed. Thanks!

Long-range image taken on March 28:

https://photojournal.jpl.nasa.gov/catalog/PIA21401

Click to view attachment

The brightness of the Occator faculae is pretty subdued at this lighting and viewing angle.

Dawn has lost another (third) reaction wheel. But it looks like the opposition studies scheduled for Saturday the 29th will not be affected.

Dawn Status Report

Opposition observation data received! https://dawn.jpl.nasa.gov/mission/status.html

Man, if I ever win the lottery I'm going to work on making longer-lasting reaction wheels for space missions.

There are many old spacecraft with great reaction wheels still working fine. But there must have been some batch - some particular hardware version rev that has hit Kepler and Dawn.

Movie from opposition observations released: https://www.jpl.nasa.gov/news/news.php?feature=6845
New journal soon, presumably.

Dawn's fate to be decided soon. Sending it off to a new asteroid is one option back on the table.

SpaceFlight Now article

Yep, here's a comment from this article ( https://spaceflightnow.com/2017/06/17/dawn-...ecrafts-future/ )

Benjamin Hunt
Mass and size are always an issue on spacecraft, especially deep space probes. Remember, however, that Dawn is an exception in terms of reliability...while reaction wheels have failed on other missions, they all (I believe) failed *after* completing their primary missions, and usually their extended missions.

That said, the reaction wheels that have failed on Dawn and several other spacecraft that have made the news have been noted as coming from a bad batch made by Ithaco Space Systems. The decreased lifespans weren't understood until it was far too late to do anything about it, except for the Kepler mission; those wheels were sent back to Ithaco for preventative maintenance shortly before launch, but even that didn't fix the problem. Still, Kepler made it 4 years before failure compared to its planned 3.5 year mission, and it is still returning very useful science, even if at a reduced capacity.

It would be fantastic news if the budget allowed for another asteroid flyby - I'd be pretty surprised though if the idea was approved.

Just a fun thought, would it be possible for Dawn to make it back to Earth? The idea of it matching orbits with the ISS and being examined up close after ten years of spaceflight is strangely thrilling (well to me at least )

It'd be possible to make it back to the Earth's vicinity, but probably only as a flyby. I don't see any practical way to get it into near-Earth orbit, even if the attitude control suite was fully operational.

No value added there. An asteroid flyby would be a much, much better option.

What about a Europa flyby, with some asteroid flybys en-route? Not sure about the gravity gradient, but it might be more efficient to head inward and get an orbital assist from Mars, or it might not. Given the current state of knowledge about Europa, we could probably learn a lot from a targeted flyby -- and probably 10 or more years before we have an orbiter in place.

Europa? No way it'll survive that far from the Sun and that sort of radiation dose. It really is Adiona, or Ceres. That's honestly all the options.

Another asteroid flyby would be cool, but I'd like to stay at Ceres to monitor it though perihelion to see if any changes/outgassing can be detected.

Perihelion is next April, and it does seem as if most water vapor detections by remote sensors have happened around then.

I concur with Ted.

I agree, stay at Ceres, but in a long term parking orbit that would allow for long term observations, with possible dips to a close orbit for flybys of anything interesting. I doubt we'll see significant changes, but maybe we'll get lucky. Occator crater is such an enigma, with the youth of the central mound. It is fascinating that two icy bodies (Ceres and Enceladus) that span an order of magnitude of sizes have localized activity.

True, only 28% as much solar energy at Jupiter (if I did the math right). Not sure if this is more a problem for propulsion or simply keeping the electronics running. And I have no expertise in judging the radiation problem, though (having been a software developer once upon a time), I do wonder whether radiation tolerant software could be developed -- perhaps using the RAM in a multiply redundant fashion -- but that's a broader problem.

Anyway, my vote would be to go elsewhere if possible, with the argument being that flyby observations of another -- never explored -- asteroid would be more valuable than spending a bit more time at Ceres.

"Ceres' Temporary Atmosphere Linked to Solar Activity ... Villarreal and colleagues showed that past detections of the transient atmosphere coincided with higher concentrations of energetic protons from the sun. Non-detections coincided with lower concentrations of these particles. What's more, the best detections of Ceres' atmosphere did not occur at its closest approach to the sun. This suggests that solar activity, rather than Ceres' proximity to the sun, is a more important factor in generating an exosphere."

I would like to stay up Ceres to the perihelion. However, it depends on which asteroid destination Dawn team proposing.

It is confirmed that Dawn will stay at Ceres. From now until the end of mission they will try to get into a closer orbit than ever before (at periapsis in a highly elliptical orbit), photograph the southern hemisphere with favorable lighting and observe Ceres at it closest point to the sun. The last part is in April with the greater possibility of Ceres outgassing an atmosphere.

October 19 Press Release

October 31st Dawn Journal

Many details in the latest Dawn Journal: https://www.jpl.nasa.gov/blog/2017/12/dear-...awnce-travelers

Descent to lower orbit should start in April, though targeting of specific areas for higher resolution imagery is not guaranteed.

Where is Dawn? Notices on extended mission?

I'm assuming no news is good news, they are still spiraling down to the final orbit. Should be in an intermediate orbit May 14th, according to the last journal, and then May 31st to finish off.

Journal update: http://www.planetary.org/blogs/guest-blogs...elliptical.html
Ceres reached perihelion, all is well with Dawn....

Sharpened and enlarged views of Occator crater's eastern rim, boulders and landslides from altitude 44-48 km:

Click to view attachment
from PIA22524

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from PIA22525

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from PIA22526

Really neat limb view here: https://photojournal.jpl.nasa.gov/catalog/PIA22522
New journal entry posted; looks like EOM is estimated for September, October at the latest:
http://www.planetary.org/blogs/guest-blogs...lling-down.html
Running out of hydrazine for manouevres is not exactly a dramatic end, but what a journey it will have been!

do you think of new, close-up images of Mount Ahuna??

This is new images of Ceres?I do not find them update dawn nasa, or in another webasite, why?

You can find those images here.

For unkown reasons they do not update twitter feed anymore since Dawn started descent to XAMO7 orbit on may 31th.

Thanks :-)

I wanted to show My model of Ahuna Mons, with my hands (12x17 cm - 1cm about 1260 km) NO 3Dprinter (in the link there is also my occator crater):

I do not know if I can to insert here or remove moderator

http://antidotumtarantulae.altervista.org/...ula_planet.html

Cerealia Facula in Occator Crater:

Click to view attachment

https://photojournal.jpl.nasa.gov/catalog/PIA22477

I dare not speculate.

Vinalia Faculae, also in Occator:

Click to view attachment

https://photojournal.jpl.nasa.gov/catalog/PIA22478

Occator floor fractures:

Click to view attachment

https://photojournal.jpl.nasa.gov/catalog/PIA22551