Dawn's last mission extensions at Ceres, From XMO3 to EOM Options

[Holder of the Tw...]

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

[TheAnt]

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.

[ngunn]

Now why only a single such feature?

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).

[Gladstoner]

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.

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



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.

[TheAnt]

@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.

[Gladstoner]

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.

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

[Daniele_bianchin...]

" 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

[Daniele_bianchin...]

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

[Paolo]

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

Localized aliphatic organic material on the surface of Ceres

Organic compounds occur in some chondritic meteorites, and their signatures on solar system bodies have been sought for decades. Spectral signatures of organics have not been unambiguously identified on the surfaces of asteroids, whereas they have been detected on cometary nuclei. Data returned by the Visible and InfraRed Mapping Spectrometer on board the Dawn spacecraft show a clear detection of an organic absorption feature at 3.4 micrometers on dwarf planet Ceres. This signature is characteristic of aliphatic organic matter and is mainly localized on a broad region of ~1000 square kilometers close to the ~50-kilometer Ernutet crater. The combined presence on Ceres of ammonia-bearing hydrated minerals, water ice, carbonates, salts, and organic material indicates a very complex chemical environment, suggesting favorable environments to prebiotic chemistry.

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

[TheAnt]

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.

[Explorer1]

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...

[fredk]

lack of atmosphere

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.

[Explorer1]

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.

[Daniele_bianchin...]

?
Is expected to map temperatures of Ceres? I expected Already for long 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.

[PhilipTerryGraha...]

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.

[Habukaz]

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

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.

[Daniele_bianchin...]

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....

[nprev]

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!

[Gladstoner]

Long-range image taken on March 28:

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



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

[Holder of the Tw...]

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

[Explorer1]

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

[hendric]

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

[djellison]

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.

[Explorer1]

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

[Holder of the Tw...]

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

SpaceFlight Now article

[hendric]

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.

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.

[jasedm]

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 )

[nprev]

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.

[algorimancer]

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.

[djellison]

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.

[tedstryk]

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.

[nprev]

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.

[hendric]

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.

[algorimancer]

Europa? No way it'll survive that far from the Sun and that sort of radiation dose...

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.

[bobik]

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

"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."

[Daniele_bianchin...]

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

[Holder of the Tw...]

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

[Explorer1]

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.

[Daniele_bianchin...]

Where is Dawn? Notices on extended mission?

[Explorer1]

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....

[Therion]

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



from PIA22524



from PIA22525



from PIA22526

[Explorer1]

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!

[Daniele_bianchin...]

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



from PIA22524



from PIA22525



from PIA22526

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

[Daniele_bianchin...]

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



from PIA22524



from PIA22525



from PIA22526

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

[charborob]

You can find those images here.

[Guest_mcmcmc_*]

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

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

[Daniele_bianchin...]

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

Attached thumbnail(s)

 

[Gladstoner]

Cerealia Facula in Occator Crater:



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

I dare not speculate.

[Gladstoner]

Vinalia Faculae, also in Occator:



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

[Gladstoner]

Occator floor fractures:



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

[Explorer1]

Amazing! I do not see a single crater in the top mosaic. A surface as young and fresh as Sputnik Planum on Pluto?

[Therion]

Amazing!
I really didn't expect we will see this thru Dawn's eyes.
Trully extraordinary engineering and mission planning accomplishment.

Reversed perspective of that mosaic makes more sense for my brain:



Occator context image

[Hungry4info]

Approximate location of two of these images overlaid on the PIA 20350 image.

Attached thumbnail(s)

 

[Floyd]

Many thanks for the context Hungry4info

[GS_Brazil]

Reversed perspective of that mosaic makes more sense for my brain:

Every brain works different ;-) My brain prefers to original, not the reversed.

Anyone knows if they were able to get more images of the area, or just the ones we saw today?

[Gladstoner]

It kind of looks like tiramisu

[wildespace]

My quck ICE version:



I tried using colour from an earlier colour image, but there is strong purple fringing there.

Of course, would be nice to see the central dome in such resolution.

[Guest_mcmcmc_*]

is it a lake or a hill?!?
Are photo metadata available?

[wildespace]

is it a lake or a hill?!?
Are photo metadata available?

"The geometry of this feature is similar to a mesa or large butte with a flat top." http://photojournal.jpl.nasa.gov/catalog/PIA22477

A sodium carbonate-topped hill. Interesting that some of it streaked downslope.

P.S. Actually, looking at it in the surrounding context, it's more like a cliff or escarpment, because the south-western side of it seems to be level with the dark part of terrain, whereas north-east side drops off sharply towards the main mound.



Most of the flat white area here is slightly darkened, probably by space weathering and dust, but the bright edges with downslope streaks reveal fresher material. I wonder what it means in terms of dynamic processes on Ceres.

[Daniele_bianchin...]

It seems like exposure of sulfur after volcanic eruption, but this should be salt or sodium carbonate [wildespace].

[HSchirmer]

It seems like exposure of sulfur after volcanic eruption, but this should be salt or sodium carbonate [wildespace].

Looks like the travertine springs in Pamukkale, Turkey.



Bigger
https://upload.wikimedia.org/wikipedia/comm..._panorama_2.jpg

[Gladstoner]

My eyes are seeing something like this:





1. Bedrock (or 'bedrock')

2. Talus made up of fragmented bedrock

3. White material deposit

4. Scattered debris atop white material

5. Eroding white material

[Paolo]

the Max Planck Institute site also has a striking image of the rim of Occator crater:
http://www.mps.mpg.de/Dawn-Unique-Views-of-Occator-Crater

[Jaro_in_Montreal]

Finally a closeup: Cerealia Facula in Occator Crater, Ceres.

[Daniele_bianchin...]

I have Searched The areas seen so far at high resolution in Occator crater:

Attached thumbnail(s)

 

[Gladstoner]

Mosaic of Cerealia Facula in Occator Crater:

https://photojournal.jpl.nasa.gov/catalog/PIA21924

Mosaic of the Vinalia Faculae in Occator Crater:

https://photojournal.jpl.nasa.gov/catalog/PIA21925

[Explorer1]

New Dawn journal, detailing how the images were obtained, and the last ion engine firing: http://www.planetary.org/blogs/guest-blogs...-on-a-high.html

[Therion]

Oh my! Those mosaics are absolutely stunning!

I see lot of pockmarks (pits/craters) on that white surface, although gray material within linear troughs/chasms and around that flat elevated mesa at SW is rather smooth.

Those bright fluvial features streaming down from flat-top mesa seems to be mixing with darker stuff which then covers underlaying bright deposits. I wonder, how amazing look would it be, standing down there next to central dome and looking SW at those streams!

Streams and landslides within troughs seems to be the youngest geological features here. Or those pockmarks all around the bright stuff are not impacts, but rather some sublimation-pits or even cryovolcanic calderas??

Either way, it's crazy landscape..

[Guest_mcmcmc_*]

Each pixel should cover around 3-3.5 meters in these images.

[Daniele_bianchin...]

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



from PIA22524



from PIA22525



from PIA22526

Finally a closeup: Cerealia Facula in Occator Crater, Ceres.

Your images are enlarged more than those inserted on: https://dawn.jpl.nasa.gov/multimedia/images/ceres.html
WHy? I would like to see these bigger,

Like these: https://www.jpl.nasa.gov/images/dawn/20180716/PIA21924.jpg

we would not have great images of Hauna mons if I understood correctly but only of crater 0ccator . .

Why did not we have temperature maps for Ceres?
..
.

[Gladstoner]

It is proving quite difficult to visualize topography in the Cerealia Facula mosaic. For instance, the fractures keep appearing as ridges to my eyes.

Is it yet possible to produce 3D images, or lay portions or all of the mosaic on an elevation model?

[Floyd]

Save the image on you computer, open in an editor and rotate 180 degrees. Light is coming from wrong angle for your brain to work--mine too--till flipped

[Gladstoner]

Save the image on you computer, open in an editor and rotate 180 degrees. Light is coming from wrong angle for your brain to work--mine too--till flipped

I already did that, and now it looks like the light is coming from below.

The extreme light-dark pattern really fools the eyes.

[wildespace]

Is it yet possible to produce 3D images, or lay portions or all of the mosaic on an elevation model?

Someone made this 3D model: https://sketchfab.com/models/6a163a690a9b44...537eb745e24f5fa
Would be very nice to see the new imagery over this model!

[Adam Hurcewicz]

Here is my 3D version of Ahuna Mons.
I use JMars software to generate DTM and ortho texture (LAMO phase) and create CMOD model to Celestia.

https://www.youtube.com/watch?v=EMW4bXI9-o8

[Gladstoner]

Parallel structures:

https://photojournal.jpl.nasa.gov/catalog/PIA22643

[Adam Hurcewicz]

From this 2 images central peak of Urvara crater I made a composition
https://photojournal.jpl.nasa.gov/catalog/PIA22627
https://photojournal.jpl.nasa.gov/catalog/PIA22636




and comparison with old images FC21B0055129_16035075527F1C versus https://photojournal.jpl.nasa.gov/catalog/PIA22627

[Explorer1]

New Dawn journal (looks to be the penultimate one, sadly), going into detail on EOM http://www.planetary.org/blogs/guest-blogs...denouement.html

Some new images here: https://dawn.jpl.nasa.gov/multimedia/images/#gallery-1

[atomoid]

interesting paper about Ceres' polar wander on astronomy.com..not to mention a great limb shot of Occator

[Explorer1]

It's over. OIP (Orbit in Peace) Dawn!
Till we see you again....