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

[OmCheeto]

Here's text of the interview:
https://www.earthfiles.com/news.php?ID=2349&category=Science

He says the VIR (visual and infrared spectrometer) has not reported any surface ice, in particular at the bright spots. So that suggests they might be salt residue left where salty water dried or salty ice sublimated.

Moulton Howe writes the "earth files" blog , I won't say more about her. She interviewed Chris Russell principal investigator for the Dawn mission (their top planetary scientist).
Dotini is right that it was a good interview!

When I first saw the interview, it looked very interesting. But then I googled Linda's name, and decided I would get an insta-ban should I even mention her name!

I'm guessing that that Chris did this, as intra-solar system science is turning out to be even more outlandish than aliens.

Pluto looks to me, more Earth-like, than any other planet in the system. Very weird.

However, on Pluto, the “snow” is the carbon monoxide, methane and nitrogen, while the “dirt” is water ice.

Water ice is dirt? Ultra weird!

 

[marcus]

Rayman posted a status update:
=quote=
September 21, 2015 - Dawn Conducting Fourth Mapping Cycle

Dawn began its fourth mapping cycle on Sept. 19 at 10:13 p.m. PDT. The probe has now completed two of the 12 revolutions needed to photograph the dwarf planet's entire surface.

For this mapping cycle, the spacecraft points its camera and spectrometers at the scenery ahead and to the left as it orbits at an altitude of 915 miles (1,470 kilometers). Together with the pictures from the other mapping cycles, the different views will allow scientists to develop topographical maps. The visible and infrared mapping spectrometers, which observe a smaller area than the camera, are continuing to study previously unobserved regions with each new mapping cycle.
=endquote=

As I said earlier, I gather from remarks by the principal investigator Chris Russell that the spectrometers have not detected ice on the surface---meaning that the "bright spots" are more likely to be salt residue from ice or water that has evaporated.

Ice would not last long in the vacuum, on surface. However SOME of the bright spots could be fresh ice. Some process (e.g. impact) could cause melting in the subsurface ice layer and cause small amounts of water to seep up to the surface, where it would freeze and exist for a while as ice. It would eventually sublimate leaving whatever salt residue. But there might be some ice fields currently for the spectrometer to detect.

Dawn will make 6 complete coverages ("mapping cycles) at altitude 1450 km, and it's already into the fourth. Seems likely that it would have detected ice if there was any on the surface.

Gamma and neutron spectroscopy at 375 km altitude (beginning December) will be able to sense water below the surface.
View attachment 88403View attachment 88402

 

[OmCheeto]

Mission [finally ] accomplished.

ps. I sent him a couple of post script message/questions also.
Did Christopher Russell really do an interview with Linda Moulton Howe?
Are you excited about seeing "The Martian"?

And... Success!

I've inserted a comment where his response may seem out of the blue.

2015.09.22.1255 PDT
Hi [Om],

{me; I understand that there is currently a “gag order” on some of the information regarding Ceres due to an upcoming article in the “Nature” journal, so no need to apologize if you can’t expand...}​

You kindly acknowledged the embargo on results, but still I'm sorry I can't give you more informative answers.

Yes, the spectroscopy provides insight into the composition of the surface, and information on that will be released when the science team, peer-reviewed journal, and media relations office collectively are ready to do so. The issue date for the journal has not been decided yet. Feel free to check back with me, but it can take a while for the papers to make their way through the review process. I don't believe I can say anything about the nature of the papers.

The visible and IR spectroscopy show chemical composition. Molecules and compounds tend to have spectral signatures in those wavelength ranges. Elemental composition, however, is different. The atomic constituents are determined from the two nuclear spectroscopic techniques. Neutron and gamma ray spectra reveal what kinds of atoms are there. We will not have those results until Dawn is in its lowest orbit. I have written about this before, including on August 31, 2014.

Even well before Dawn arrived at Ceres, there was much speculation within the science team about the possibility of pingos there. Indeed, the team has expertise in such structures, and some of the geologists studied them specifically for that reason. For the mountain to be a pingo, it would have to be a uniquely large one. In addition, it is not yet certain that the conditions for forming a giant pingo really can occur on Ceres. So, it's a very intriguing idea, and for now remains an open question.

I've been interviewed by Linda Mouton Howe too. I like your description of her, and I'm going to pass that along to some people here whom I've told about some of the questions she asked me. The interview is real, but I'm not sure what exactly you have in mind. In such a long running interview, some comments may come out a bit confusing.

I greatly enjoyed the novel The Martian, and yes, I'm very much looking forward to the movie. (Bland as it may make me sound, however, I prefer science to science fiction.) I had an opportunity to see an advanced screening but had to decline because I had a conflict. Are you looking forward to it?

Regards,

Marc

 

[marcus]

==mission director's update==
September 25, 2015 - Dawn Conducting Fourth Mapping Cycle

Dawn has completed more than half of its fourth mapping cycle, acquiring more stereo pictures as well as spectra in infrared and visible wavelengths. Today the ship will make its eighth transit over the hemisphere of Ceres lit by the sun.
==endquote==

 

[marcus]

Dawn Journal 27 September
http://dawnblog.jpl.nasa.gov/2015/09/27/dawn-journal-september-27-2/

 

[marcus]

==quote mission update==
September 28, 2015 - Fourth Mapping Cycle Nearly Complete

This afternoon Dawn will begin the 12th and final observation session in its fourth mapping cycle. Upon completing this last flight over the illuminated hemisphere, the spacecraft will point its main antenna at Earth for two days to transmit the many pictures and spectra it has acquired.

On Sep. 27, Dawn celebrated its eighth anniversary of being in space. This month's Dawn Journal looks at the spaceship's progress on its interplanetary travels.
==endquote==

 

[OmCheeto]

Twitter is atwitter about the cornucopia of images just released:

Parent article: Dawn Team Shares New Maps and Insights about Ceres

Sub articles:

Topographic View of Ceres Mountain
Occator Topography
Hints at Ceres' Composition from Color
Topographic Ceres Map with Feature Names II​

A tad confusing, as they color code the images differently.

 

[OmCheeto]

I'm starting to understand why no one wants to make a guess about what's going on with the "Lonely Mountain".
From the false color image(left), there's really nothing outstanding about it.
It's just a mountain, with freaky streaks.

double hmmmm...

My extraction from the two big images.
​

It took me forever to find the left image, as they didn't provide lat/long marks on the parent image. (location: 11°S 316°E)

 

[Dotini]

Amazing images and a surprise observation.

http://scitechdaily.com/dawn- spacecraft -reveals-new-maps-and-insights-about-ceres/

This view, made using images taken by NASA’s Dawn spacecraft , is a color-coded topographic map of Occator crater on Ceres. Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDAA surprising bonus observation came from Dawn’s gamma ray and neutron spectrometer. The instrument detected three bursts of energetic electrons that may result from the interaction between Ceres and radiation from the sun. The observation isn’t yet fully understood, but may be important in forming a complete picture of Ceres. “This is a very unexpected observation for which we are now testing hypotheses,” Russell said.

This color-coded map from NASA’s Dawn mission shows the highs and lows of topography on the surface of dwarf planet Ceres. It is labeled with names of features approved by the International Astronomical Union. Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

 

[marcus]

Nice finds, Dotini!
I have links to some papers presented at the Ceres session of a European space conference last week, in Nantes, France. But nothing as striking as what you just posted. For completeness, here they are.
Ceres session, a few of the many papers, presented at the Nantes conference:
http://meetingorganizer.copernicus.org/epsc2015/sessionprogramme

http://meetingorganizer.copernicus.org/EPSC2015/EPSC2015-400.pdf
Impact Craters on Ceres: Evidence for Water-Ice Mantle?

http://meetingorganizer.copernicus.org/EPSC2015/EPSC2015-490-1.pdf
Ceres: ice stability and water emission

http://meetingorganizer.copernicus.org/EPSC2015/EPSC2015-525.pdf
Color variations on Ceres derived by Dawn/VIR: Implications for the surface composition

 

[marcus]

==Rayman's latest update==

October 1, 2015 - Dawn Begins Fifth Mapping Cycle

After sending the last of its data from the fourth mapping cycle to Earth, Dawn started its fifth mapping cycle on Sep. 30 at 11:40 p.m. PDT. During this 11-day period, the tireless explorer will aim its sensors toward the terrain immediately ahead as it orbits the alien world at an altitude of 915 miles (1,470 kilometers). This new angle will provide scientists with another stereo view to use in developing 3-D perspectives.

This morning Dawn completed the first transit in this cycle over the side of Ceres facing the sun. The dwarf planet turns on its axis in nine hours, and the spacecraft revolves around it in 19 hours, spending half that time over the sunlit landscape and half over the ground hidden in the dark of night. With 12 orbital loops, Dawn's camera can see all of the terrain.
==endquote==

 

[marcus]

Dawn's six mapping cycles in HAMO are nearing completion
==Rayman, 5 October update==

October 5, 2015 - Fifth Mapping Cycle Half Complete

Dawn conducted its sixth observing session in mapping cycle #5 today, spending more than nine hours photographing Ceres and collecting more spectra.

Since entering orbit in March, Dawn has completed more than 100 revolutions around the dwarf planet, with 62 of those occurring since the start of this third mapping phase on Aug. 17.
==endquote==

Orbit    dates      altitude(km)  pixelsize(m) res/HST  period  soccerball at
RC3    April 23–May 9    (13,600)    (1,300)    24     15 days    (3.0 meters)
Survey    June 6-30      (4,400)      (410)     73     3.1 days    (1.0 meters)
HAMO    Aug 17–Oct 23    (1,470)      (140)     217    19 hours    (33 cm)
LAMO Dec 15–end of mission (375)      (35)      850    5.5 hours    (8.5 cm)

For me personally, the real meat of the results will only start coming in December when the probe finally gets down to 375 km altitude and can make effective use of gamma and neutron spectrometers for tasting the chemistry of Ceres' surface layer to a depth of about one meter.

The final descent, from altitude 1470 km to 375 km, will be long and arduous, because so much more gravitational potential energy is involved, closer into the planetto. You can see it will take nearly 8 weeks of work with the solar-powered ion engine to get down to LAMO.

 

[OmCheeto]

...
For me personally, the real meat of the results will only start coming in December when the probe finally gets down to 375 km altitude and can make effective use of gamma and neutron spectrometers for tasting Ceres' surface chemistry down to a depth of about one meter.
...

Me too! I've been going over the posts and references [see below] since August, trying to figure out how the neutron detectors can differentiate between fast and slow ones, but it all looks like black magic to me.

I also checked out a couple of other references:
Dawn’s GRaND to reveal the complex geochemistry of Vesta [lpi.usra.edu] (Where I learned that Vesta is covered in "Howardite")
Scintillation counter, Neutron detector efficiency [wiki] (Told me absolutely nothing. My apologies if you clicked on the link.)
PDS: The Planetary Data System, GAMMA-RAY AND NEUTRON DETECTOR [nasa] (Where I learned that "GRaND is mounted on the +Z deck of the spacecraft ". Woo Hoo!)

I used to be a nuclear trained technician in the USN, where they made us study neutron detector theory. But after 35 years, it's all a bit fuzzy now.

ps. I surfed through at least 15 other websites, and didn't learn very much, other than rocks from Vesta are named after someone named Howard: Howardite
I thought that was very funny.
Sorry.Previously referenced references:
[1] Gamma Ray and Neutron Spectrometer (GRNS) [messenger-education.org]
[2] Planetary gamma-ray spectrometers [wiki]
[3] DAWN JOURNAL | OCTOBER 29, 2006, re: GRaND [jpl]

 

[OmCheeto]

Just in case anyone interested in the mission missed the announcement:

Get your popcorn ready!

(About 90 minutes from now, for those of you not on the west coast of the USA)

 

[marcus]

A lecture by Carol Raymond, deputy principal investigator. Starts at 7 PM pacific at this website:
http://www.ustream.tv/nasajpl2

Here's a bit about the lecture:
http://www.jpl.nasa.gov/events/lectures_archive.php?year=2015&month=10

I gather that Dr. Raymond will be giving it twice each time at 7 PM pacific, on Thursday 8 Oct and Friday 9 Oct.

 

[OmCheeto]

A lecture by Carol Raymond, deputy principal investigator. Starts at 7 PM pacific at this website:
http://www.ustream.tv/nasajpl2

Here's a bit about the lecture:
http://www.jpl.nasa.gov/events/lectures_archive.php?year=2015&month=10

I gather that Dr. Raymond will be giving it twice each time at 7 PM pacific, on Thursday 8 Oct and Friday 9 Oct.

Did you watch it?
Was I mistaken, or did she not say they didn't know what the bright spots were?

I watched a video yesterday that kind of contradicted that:

European Planetary Science Congress
27 Sept - 02 Oct 2015
2015 EPSC Opening Ceremony: C. Russell


Regarding the "bright spots" in Occator Crater:
@ t = 15:30
"Eventually, we found the albedo, and that ruled out ice.
So we believe this is a huge salt deposit.
It tells me, that this is an active surface".
​

Not that it makes much of a difference to me.

But, hmmm...
Ah ha!

Never mind.

 

[marcus]

I watched some of Dr. Raymond's talk---it was for wide audience. Thanks for the link to Chris Russell's more informative EPSC opening talk, more for professional audience. I heard the same remark you did---not ice but rather salt. The fraction in the icy mantle is now estimated at 20%, it seems. He said the surface is clay-ey rather than regolith. If I understood correctly the current best guess model is a small core which may have metal surrounded by a thick layer of "hydrated minerals" then a layer of ice (thinner than that shown in earlier guesses but still some 50-100 km thick) and then a dry clay-like surface.

 

[OmCheeto]

I watched some of Dr. Raymond's talk---it was for wide audience. Thanks for the link to Chris Russell's more informative EPSC opening talk, more for professional audience. I heard the same remark you did---not ice but rather salt. The fraction in the icy mantle is now estimated at 20%, it seems. He said the surface is clay-ey rather than regolith. If I understood correctly the current best guess model is a small core which may have metal surrounded by a thick layer of "hydrated minerals" then a layer of ice (thinner than that shown in earlier guesses but still some 50-100 km thick) and then a dry clay-like surface.

My "Ah ha!" comment was based on my perception that JPL may be playing the media, to gather attention.

Faux Headline:

Top scientists fighting at JPL!
JPL's Dawn PI says it's salt, while the deputy PI says they don't know.
Intra-stellar smackdown at 7​

They did refer to Ahuna Mons as a "pyramid".

 

[newjerseyrunner]

I have a question, why can't a spectral analysis tell us what the bright spot's made out of?

 

[mfb]

It will, but Dawn has to go to the lower orbit to do sensitive spectroscopy.

 

[marcus]

New status update from Rayman:
==quote==

October 9, 2015 - Fifth Mapping Cycle Wrapping Up

Dawn will start its 12th and final passage in mapping cycle #5 over the dayside of Ceres this afternoon. After completing these observations at 1:31 a.m. PDT tomorrow, the spacecraft will aim its main antenna to Earth. It will take about two days to radio all of its photos and other data to NASA's Deep Space Network. Dawn will orbit Ceres 2.5 times while it is transmitting its findings.

The final mapping cycle in this phase of the mission will begin on Oct. 12.
==endquote==

 

[OmCheeto]

It will, but Dawn has to go to the lower orbit to do sensitive spectroscopy.

As I pointed out to someone on social media the other day, Dawn is still 900 miles from Ceres, which is about the distance of JPL in Pasadena, to Seattle.

I bought an http://www.radioshack.com/radioshack-ir-thermometer/2200170.html early this year, and played with it to no end.
Two odd peculiarities showed up:

1. It could not correctly measure the temperature of polished metal
2. It could not correctly measure the temperature of wet (wink wink) sand​

If I can't get an accurate IR reading from 1 foot away, how on off Earth can you do it from 900 miles away?
IMHO, these people are rocket scientists!

 

[mfb]

It could not correctly measure the temperature of polished metal

It reflects most of the infrared radiation, so you actually measure the temperature of objects that get reflected (to a good approximation). Good thermometers can consider that with a known room temperature and surface reflectivity. The typical solution is to cover the metal, however - with tape, paint, or something similar.

If I can't get an accurate IR reading from 1 foot away, how on off Earth can you do it from 900 miles away?

As long as the surface is homogeneous in your measurement direction, distance does not matter. The angular resolution can be an issue.

 

[marcus]

Deep Space Network
https://eyes.nasa.gov/dsn/dsn.html
now shows Dawn transmitting at 125 kilobit per second to Madrid antenna 54. that means it has finished recording all the pictures and data for mapping cycle #5 and is now taking a couple of days to send it to us.

Dawn will start the sixth and final HAMO mapping cycle on Monday 12 Oct, Rayman says.

 

[marcus]

From mission director Marc Rayman:

October 12, 2015 - Final Mapping Cycle Underway

Dawn transmitted the last of its measurements from mapping cycle #5 yesterday and started its sixth mapping cycle today at 1:40 a.m. PDT. Mapping cycle #6 will consist of 12 flights over the sunlit terrain, during which the explorer will aim its sensors at the scenery farther behind than in the third mapping cycle but not as far to the right. The pictures will add to scientists' determination of the topography of this alien world. This will be the last set of observations made at the current altitude of 915 miles (1,470 kilometers).

 

[OmCheeto]

... This will be the last set of observations made at the current altitude of 915 miles (1,470 kilometers).

Good!
I'm starting to hallucinate looking at the pictures from this altitude.

zoomed capture of crater from JPL PIA19972 image​

Yes. I know. I was supposed to look at the "fractured" set of looking features, off to the right.

PIA19972: Dawn HAMO Image 34​

low-res capture​

 

[marcus]

Ceres sends her love.

 

[OmCheeto]

Ceres sends her love.

Ha ha! I didn't notice that.

I saw a squirrel, with wings, in a peregrine falcon dive, flying out towards us.

Actually, it was the landslide cleavage, just below the crater rim, at about the 10:30 position, that caught my eye.
It looked very plate tectonic, rotating clockwise, with the fulcrum being at about 9:15.

I should probably wait for JPL to analyze the photos...

 

[marcus]

A new update from Rayman:
==quote==

October 16, 2015 - Dawn Halfway Through Sixth Mapping Cycle

This morning Dawn completed observations during its sixth transit over the dayside of Ceres in mapping cycle #6. The spacecraft is continuing to operate extremely well.

The flight team is now developing the detailed flight profile and the associated instructions the probe will follow for its spiral descent from this third mapping orbit to the fourth and final orbit, which it will reach in December. Ion thrusting is scheduled to begin on Oct. 23.
==endquote==

 

[OmCheeto]

A new update from Rayman:
==quote==

October 16, 2015 - Dawn Halfway Through Sixth Mapping Cycle

This morning Dawn completed observations during its sixth transit over the dayside of Ceres in mapping cycle #6. The spacecraft is continuing to operate extremely well.

The flight team is now developing the detailed flight profile and the associated instructions the probe will follow for its spiral descent from this third mapping orbit to the fourth and final orbit, which it will reach in December. Ion thrusting is scheduled to begin on Oct. 23.
==endquote==

I'm feeling like a kid, sitting in the back seat, just blocks away, from the candy shop.

 

[marcus]

Yes! I know the feeling! I'm already tasting the December results, even though realizing it will take 2 months of ion-drive work to get down to altitude 375 km.
Have to think about something else to pass the time. The Hamo mapping (terrain from 6 different angles) should produce some really nice 3D contour maps.

 

[marcus]

Latest update from Rayman:
==quote==
October 19, 2015 - Final Mapping Cycle Continuing Smoothly

Dawn is flying over the lit hemisphere of Ceres for the 10th time in the final mapping cycle, taking pictures and measuring spectra. After it completes the 12th revolution on Oct. 21, it will turn to point its main antenna to transmit the data to Earth.
==endquote==

As a reminder I'll bring forward the projected schedule.

...

Orbit    dates      altitude(km)  pixelsize(m) res/HST  period  soccerball at
RC3    April 23–May 9    (13,600)    (1,300)    24     15 days    (3.0 meters)
Survey    June 6-30      (4,400)      (410)     73     3.1 days    (1.0 meters)
HAMO    Aug 17–Oct 23    (1,470)      (140)     217    19 hours    (33 cm)
LAMO Dec 15–end of mission (375)      (35)      850    5.5 hours    (8.5 cm)

For me personally, the real meat of the results will only start coming in December when the probe finally gets down to 375 km altitude and can make effective use of gamma and neutron spectrometers for tasting the chemistry of Ceres' surface layer to a depth of about one meter.

The final descent, from altitude 1470 km to 375 km, will be long and arduous, because so much more gravitational potential energy is involved, closer into the planetto. You can see it will take nearly 8 weeks of work with the solar-powered ion engine to get down to LAMO.

And a detail from Dawn's HAMO image #34 that Om captured:
a

 

[marcus]

Here's the original post where Om gives the source of that image, which he zoomed in on.

zoomed capture of crater from JPL PIA19972 image​

Yes. I know. I was supposed to look at the "fractured" set of looking features, off to the right.

PIA19972: Dawn HAMO Image 34​

low-res capture​

 

[OmCheeto]

For me personally, ...

Given the lack of time travel, I've been sleeping 14 hours a day trying to get to LAMO, asap.

 

[Garth]

Given the lack of time travel, I've been sleeping 14 hours a day trying to get to LAMO, asap.

What? No time travel? On this the 21st October 2015 - 'Back to the Future II' day?

Garth