I Dawn dead in Ceres orbit, ran out of fuel Oct 2018

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The Dawn spacecraft successfully observed Ceres from a distance of 238,000 miles on January 13, 2015, capturing over half of its surface at a resolution of 27 pixels. The mission aimed to enter a polar orbit around Ceres, with a planned descent to an altitude of 375 km, but faced challenges due to limited hydrazine propellant for attitude control. A cosmic ray event in September 2014 had previously disrupted the propulsion system, complicating the approach trajectory. Despite these issues, the spacecraft was expected to achieve a stable orbit around Ceres, ultimately becoming a "perpetual satellite" as it ran out of fuel. The mission's success would provide valuable data on Ceres' physical characteristics and surface mapping.
  • #931
- from Chief Engineer/ Mission Director, Marc Rayman (JPL)
2016
May 13 - Another Lucky Day for Dawn

"On this Friday the 13th, Dawn is maintaining its long streak of good
luck (supplemented with some skill) in exploring Ceres. The spacecraft
began transmitting its most recent pictures and spectra to Earth
yesterday and will finish late this morning. It will resume observing the
dwarf planet around noon".

I'll keep an eye out for the latest images,hope to post some soon.
 
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  • #932
1oldman2 said:
I'll keep an eye out for the latest images,hope to post some soon.
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PIA20571_hires.jpg

PIA20570_hires.jpg

:smile:
 
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  • #933
And last but not least :smile:
PIA20668_hires.jpg
 
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  • #934
That double crater in the last picture looks weird. The craters don't overlap, they look as if they were created at the same time. Impact from split up object?
 
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  • #935
Or, less likely, some kind of strong rigid material dividing the craters that resisted impact. That the craters are approximately the same age favors the simultaneous impact theory.
 
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  • #936
double crater zoom.PNG

Here is a zoom view.
 
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  • #937
mheslep said:
Or, less likely, some kind of strong rigid material dividing the craters that resisted impact. That the craters are approximately the same age favors the simultaneous impact theory.
They do resemble clones of one another, I'm going to see if there are any comments from JPL on this feature, I honestly hadn't focused on it until mfb mentioned it. The center ridge does seem to have a darker material. I suspect both of you may be correct, if I find anything out I'll mention it in a post.
 
  • #938
A couple of other features that have me curious, the material on the crater rim in the top left corner of the first image, and on the flanks of AH in the second image there seems to be significant amounts of the "bright white material". I have thought of that stuff as being a deeper subsurface trait so it strikes me as out of place so high up the slopes (and that thing is relatively very high). I still haven't heard a theory on the formation of AH and wonder if that could be a clue.
Ceres crater walls.PNG


AM.PNG
 
  • #939
DISCLAIMER!... I'm not sure if this is an appropriate place for humor but while searching images I came across this and thought "what the heck, a good laugh never hurts"
Ceres UFO.PNG
 
  • #940
1oldman2 said:
DISCLAIMER!... I'm not sure if this is an appropriate place for humor but while searching images I came across this and thought "what the heck, a good laugh never hurts"
View attachment 100785
Have we seen these anomalous blobs somewhere before in this long thread? Maybe so, but I'm good with writing them off as photo defects.
 
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  • #941
Dotini said:
Have we seen these anomalous blobs somewhere before in this long thread? Maybe so, but I'm good with writing them off as photo defects.
It was you, almost a year ago, who first pointed them out.

May 18 2015
Dotini said:
Below are two stills from the animation. What are these artifacts in the images?
...

And you-know-who made a joke about them.
OmCheeto said:
I'm guessing dust on the camera lens.
The donut shaped anomaly can be seen in two other frames.
...
The only other explanation: Aliens.
:redface:
 
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  • #943
1oldman2 said:
They do resemble clones of one another, I'm going to see if there are any comments from JPL on this feature, I honestly hadn't focused on it until mfb mentioned it. The center ridge does seem to have a darker material. I suspect both of you may be correct, if I find anything out I'll mention it in a post.
This image from Ceres shows a small, double-impact crater (at bottom) near a larger
crater. The larger structure has a crater floor with roughly the same crater density, and
therefore roughly the same age, as the material outside the crater rim. Within the large
crater is a small impact scar with rays of bright material.

NASA's Dawn spacecraft took this image on March 23, 2016, in its low-altitude mapping
orbit, at a distance of about 240 miles (385 kilometers) above the surface. The image
resolution is 120 feet (35 meters) per pixel.

regarding post # 938
 
  • #944
from Chief Engineer/ Mission Director, Marc Rayman (JPL)

"May 16 - Dawn Operating Smoothly

Dawn is devoting most of today and tomorrow to sending more Ceres data to Earth.
Every three weeks, the flight team evaluates Dawn's orbit to determine whether a
small adjustment maneuver with the ion engine is needed. (These "orbit
maintenance maneuvers" were described in the February Dawn Journal.) Today the
team concluded that the orbit is so good that no maneuver is necessary."

"May 19 - Dawn Executing All Planned Observations

Dawn is hard at work observing Ceres and storing the data in computer memory.
The spacecraft is programmed to pause its measurements early on May 21, when it
will turn to point its main antenna to Earth and radio the data to JPL.

Dawn is continuing to operate in "hybrid control," using its two operable reaction
wheels in combination with hydrazine to control its orientation. Mission controllers
activated the two reaction wheels in December when the probe reached this low
altitude orbit. As long as they operate, the two wheels allow the dwindling supply of
hydrazine to be used very efficiently."

Hopefully more imaging to post soon. :smile:
 
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  • #945
1oldman2 said:
Hopefully more imaging to post soon. :smile:

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  • #946
Ahuna Mons with multiple double craters in attendance. ~450'/pixel
Impressive buttresses, aretes, columns or whatever they are. Curious talus or glacis, for want of a better word, at bases of the largest ones.
ceres5a.jpg


Chained craters, center right, lower right
ceres5b.jpg


For laughs
220px-Krak_des_Chevaliers_14.jpg
 
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  • #947
Dotini said:
Ahuna Mons with multiple double craters in attendance. ~450'/pixel
Impressive buttresses, aretes, columns or whatever they are. Curious talus or glacis, for want of a better word, at bases of the largest ones.
Ahuna Mons close up.PNG

A little closer view here, all the features you mentioned and another of those weird artifacts. I believe the term Talus is the appropriate word for the flanks of this thing. Pretty cool real estate, I hope the geology of this gets explained.
 
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  • #948
And a couple of late comers that were recently posted on the JPL site. :smile:

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  • #949
5/24 Image release.
PIA20675.jpg

Image was taken on 4/17/16 at an altitude of approximately 240 miles or 385 Kilometers
 
  • #950
Released on 5/25/16, taken same day and altitude as post #950
Expecting more data to be released soon.

PIA20676.jpg
 
  • #951
- from Chief Engineer/ Mission Director, Marc Rayman (JPL)
2016
May 26 - Dawn Completes Another Mapping Campaign

"Dawn has completed the photography of the Ceres landscapes it began on April 11,
pointing its camera slightly ahead and to the left. Combining pictures from that
perspective with the earlier pictures looking straight down makes stereo views.

The spacecraft is now transmitting its last set of pictures and other data to Earth. After
it finishes tomorrow, it will begin a new photography campaign, this time taking
pictures with the camera looking slightly ahead and to the right. These pictures will
form new stereo views, allowing further refinements in topographical maps of the alien
terrain.

Since arriving in orbit on March 6, 2015, Dawn has now completed more than 1,000
revolutions around the dwarf planet".
 
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  • #952
PIA20677.jpg
 
  • #953
:partytime:May Journal's out!
- from Chief Engineer/ Mission Director, Marc Rayman (JPL)

2016
May 31 - "Dawn Continuing to Study Ceres
Dawn is transmitting its latest pictures and spectra of Ceres to NASA's Deep
Space Network.The spacecraft is healthy and all systems are working well.
Early tomorrow morning it will resume observing the dwarf planet.

The May Dawn Journal explains how scientists use Dawn's photographs of
craters to measure the age of geological features. It also presents some
surprising information about samples on Earth from Vesta, which Dawn
explored in 2011-2012."

PIA20679_hires.jpg

May Dawn Journal
 
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  • #954
JPL seems to be releasing an image per day so I will in the future save up three or four days worth before posting them. While zooming on today's image I noticed a familiar artifact so I have posted a couple of shots showing it fairly clearly, I'm wondering if it's micro meteor damage or what it might be, any
ideas ?

PIA20680_Jun1_lg.jpg


ceres zoom June 1st.PNG


Ahuna Mons close up.PNG
 
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  • #955
1oldman2 said:
JPL seems to be releasing an image per day so I will in the future save up three or four days worth before posting them. While zooming on today's image I noticed a familiar artifact so I have posted a couple of shots showing it fairly clearly, I'm wondering if it's micro meteor damage or what it might be, any
ideas ?

...
I'm guessing, dust on the lens. We've seen similar artifacts in the past.

One more problem to solve, on our endeavors: extraterrestrial windshield wipers. :smile:
 
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  • #956
OmCheeto said:
extraterrestrial windshield wipers. :smile:
I have a patent on that!
 
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  • #957
It's odd that this artifact is triangular, and the previous ones were donut shaped: [ref: page 23, May 18, 2015]

Dr. Rayman graciously explained everything back then:

May 19, 2015 12:42 PM
Hi [Om],

I don’t have time now to look at the forum (I have only ever visited it very briefly), but the images do have artifacts. Some are the result of dust that occasionally separates from the spacecraft and, being small and out of focus, can look larger than it really is. We have observed this throughout the mission, but the flux of dust is very low and it does not compromise the scientific value of the images. There are also electronic artifacts from the CCD. Most spacecraft experience both, and image processing removes them. We are releasing images that have not yet gone through the (time-consuming) full processing, although ultimately all the data, both uncorrected and fully corrected, calibrated, will be released. Of course, all images are scrutinized for moons and other real phenomena, but we know with 100% confidence that none of the stuff we see is anything other than an artifact.

We post a new image every (work) day.

Regards,
marc [Rayman, Dawn chief engineer and mission director at JPL]
bolding mine
 
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  • #958
- from Chief Engineer/ Mission Director, Marc Rayman (JPL)
"June 6 - Dawn Operations Remain Smooth"

"After sending its most recent findings to Earth on June 4-5, Dawn is observing
Ceres again, acquiring new photographs and spectra. The mission has already
surpassed all of its original objectives for exploring the dwarf planet, and it is
continuing to collect bonus data".

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PIA20683_hires.jpg
 
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  • #959
- from Chief Engineer/ Mission Director, Marc Rayman (JPL)

"June 9 - Dawn to Adjust Orbit
Dawn started beaming more photographs and spectra to JPL yesterday, and it is continuing
today."

"Every three weeks, the flight team evaluates Dawn's orbit to determine whether an adjustment is
needed. These "orbit maintenance maneuvers" (OMMs) were described in the February Dawn
Journal. Most of the OMMs have not been necessary and so were canceled. Now a small
refinement is needed, and the first part will be executed this afternoon starting shortly after 4:00
PM. Dawn will thrust with its ion engine for about an hour. The spacecraft will perform more
small maneuvers on June 17 and 18."

PIA20646.jpg


PIA20684.jpg


PIA20685.jpg
 
  • #960
1oldman2 said:
Dawn will thrust with its ion engine for about an hour.
For an estimated delta_v of just 20 cm/s.
 
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