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

[mfb]

I'm not aware of any properly working probe that has been shut down simply because the space agency didn't want to use it any more.

 

[1oldman2]

http://spacenews.com/nasa-reviews-options-for-dawn-extended-mission/
WASHINGTON - "NASA expects to make a decision within the next two months whether to keep the Dawn spacecraft in orbit around the largest body in the main asteroid belt or have it fly past another asteroid."

 

[OmCheeto]

http://spacenews.com/nasa-reviews-options-for-dawn-extended-mission/
WASHINGTON - "NASA expects to make a decision within the next two months whether to keep the Dawn spacecraft in orbit around the largest body in the main asteroid belt or have it fly past another asteroid."

Weird. I read the latest journal the other day, and don't remember "that message".

 

[1oldman2]

Weird. I read the latest journal the other day, and don't remember "that message".

The folks at JPL don't seem to be saying much about the future of Dawn, I can't find anything but vague references to the possible upcoming mission phase but I'm sure they will come up with something soon.

 

[1oldman2]

Still no word on the next phase of Dawns mission.
from Chief Engineer/ Mission Director, Marc Rayman (JPL)
2017
August 2 - Dawn Operations Continuing

"As Dawn measures cosmic rays, it is ascending in its elliptical orbit. Its average altitude today is 22,300 miles (35,800 kilometers). For comparison, that is the altitude of geosynchronous orbit at Earth. In geosynchronous orbit, satellites circle Earth once per day, the same rate at which Earth turns on its axis. Because Ceres' mass (and hence the strength of its gravitational pull) and the length of its day are different from Earth's, synchronous orbital altitude around the dwarf planet is different. With the Cerean day of a little more than nine hours, synchronous orbit is 450 miles (720 kilometers). Dawn descended through that altitude in November 2015 and ascended past it in September 2016."

 

[mfb]

The mission has been extended until the hydrazine runs out, probably in the second half of 2018.

Until then, Dawn will take a much closer look at Ceres. While the previously lowest orbit was at 385 km, the new orbit will at a minimum distance of less than 200 km. We'll get more measurements of the gamma ray and neutron spectrometer, and of course new optical and infrared images with a higher resolution.
The orbit is expected to be stable, so Dawn will stay there even after the end of the mission.

NASA news article

 

[mfb]

https://solarsystem.nasa.gov/news/2017/10/26/dawn-finds-possible-ancient-ocean-remnants-at-ceres

supporting the idea that Ceres' deeper interior contains liquid left over from its ancient ocean.

 

[1oldman2]

https://solarsystem.nasa.gov/news/2017/10/26/dawn-finds-possible-ancient-ocean-remnants-at-ceres

Interesting reading.
http://onlinelibrary.wiley.com/doi/10.1002/2017JE005302/pdf
https://www.sciencedirect.com/science/article/pii/S0012821X17304405

 

[OmCheeto]

I was most intrigued by the fact that Ahuna Mons has the highest gravitational anomaly.

Of course, this only feeds my hypothesis as to what might be causing this, but I'll wait and see if my guess was correct.

 

[mfb]

The mountain itself causes a gravitational anomaly.

 

[OmCheeto]

The mountain itself causes a gravitational anomaly.

As do we both.
But Ahuna Mons isn't big enough to cause the anomaly.

"However, since the feature is only 17 km wide, it is not possible to associate the anomaly with the feature itself, but only with the general surrounding area. Positive anomaly in the Ahuna Mons region can be explained by an extrusion of high-density brines to the surface..."​

My guess is, that whatever is causing the anomaly, created Ahuna Mons.

ps. I'm greatly looking forward to perihelion. (April, 2018!)

 

[1oldman2]

I was most intrigued by the fact that Ahuna Mons has the highest gravitational anomaly.

View attachment 213998Of course, this only feeds my hypothesis as to what might be causing this, but I'll wait and see if my guess was correct.

Somewhere, far back in this thread I mentioned to Marcus that Ceres was going to be in demand for mining eventually. I wonder what the value of all that potential "Fossil" Ocean will be in one hundred years or so.
Curious about interpreting the map I did a little reading and thought I'd post this, a pretty good explanation overall.
https://pubs.usgs.gov/fs/fs-0239-95/fs-0239-95.pdf
"The isostatic gravity anomaly is calculated by
subtracting the gravitational effect of low-density
mountain roots below areas of high topography.
Although these roots have never been seen, their isos-
tatic effect has been measured and models calculated
using topography. Isostasy is typified by floating ice-
bergs that have 90% of their mass of ice below water
that supports a smaller mass of ice projecting above
water."
(Somewhat still on subject, and very cool also.)
https://mrdata.usgs.gov/geophysics/gravity.html
https://solarsystem.nasa.gov/galleries/flowing-in-flowing-out-of-aelia

 

[1oldman2]

https://phys.org/news/2017-11-dawn-explores-ceres-interior-evolution.html
https://www.jpl.nasa.gov/blog/2017/10/dear-frankendawns-skeledawns-and-all-other-dawn-or-treaters

 

[lpetrich]

There's an interesting conundrum about Ceres, a conundrum suggested by Vesta. That latter asteroid had gotten hot enough to melt early in the Solar System's history, most likely from short-lived radionuclides like aluminum-26. If Ceres had enough of these radionuclides, then it may have been enough to melt its interior. So could Ceres have had an interior ocean in its past? An ocean like those of Europa and Enceladus.

 

[mfb]

See post #1057. It could still have liquid water, and it looks like it had an ocean in the past. It won't be ocean-like today, however, more like wet soil.

 

[mfb]

Image source and news

The periapsis is now 35 km. There is no zero missing here. Shorter than a marathon distance.
We will get very detailed pictures of Occator Crater.

 

[OmCheeto]

If anyone is still interested in the mission:

NASA to Host Live Chat on Successful Mission to Asteroid Belt

NASA's Jet Propulsion Laboratory in Pasadena, California, will host a live-streamed Science Chat at 11 a.m. PDT (2 p.m. EDT) Friday, Sept. 7, during which experts will talk about the role of the agency's Dawn spacecraft in studying the beginning of our solar system, and the approaching end of its 11-year mission.

The event will air live on NASA Television, Facebook Live, Ustream, YouTube and the agency's website.

Participants include:

Jim Green, NASA chief scientist
Carol Raymond, Dawn principal investigator at JPL
Marc Rayman, Dawn mission director and chief engineer at JPL

The public can ask questions on Twitter using the hashtag #askNASA or in the comment section of the JPL Facebook page.​

What a wild orbit she's in right now.

34 km at periapsis!

Though the images are kind of disappointing, as they are getting so detailed, they're taking all the mystery out!

 

[OmCheeto]

NASA's Dawn Mission to Asteroid Belt Comes to End

News | November 1, 2018

NASA's Dawn spacecraft has gone silent, ending a historic mission that studied time capsules from the solar system's earliest chapter.

Dawn missed scheduled communications sessions with NASA's Deep Space Network on Wednesday, Oct. 31, and Thursday, Nov. 1. After the flight team eliminated other possible causes for the missed communications, mission managers concluded that the spacecraft finally ran out of hydrazine, the fuel that enables the spacecraft to control its pointing. Dawn can no longer keep its antennae trained on Earth to communicate with mission control or turn its solar panels to the Sun to recharge. ​

Thank you again, for the last time, Marcus, for inviting me along for the ride.
What a long strange** trip it's been.*

---------------
* Dawn is supposed to be truckin' in orbit, long after I'm Dead.
** As in weird. As in, outer space is nothing like here on planet Earth.

ps. Didn't the Kepler mission end just two days ago? Asking for a friend.

hmmmm... (google google google)

Dia de los Muertos!

The multi-day holiday focuses on gatherings of family and friends to pray for and remember friends and family members who have died, and help support their spiritual journey.​

 

[mfb]

Kepler has a successor in orbit already, TESS.
Dawn doesn't have that, but there are new asteroid missions planned:
Psyche is expected to launch 2022 towards - you guessed it - asteroid Psyche. The idea is similar: Approach, enter orbit, lower the orbit in multiple steps with an ion thruster.
Lucy is expected to perform 5 fly-bys at different Jupiter trojans after a launch 2021.
DESTINY+ is a Japanese mission towards a small (6km diameter) asteroid with an expected launch date of 2022. It will be launched to low Earth orbit and will exclusively use ion engines from there on - spending the first 1.5 years to escape from Earth. Similar to Dawn it has the capability to visit multiple objects.

 

[mfb]

Mystery Solved: Bright Areas on Ceres Come From Salty Water Below

By analyzing data collected near the end of the mission, Dawn scientists have concluded that the liquid came from a deep reservoir of brine, or salt-enriched water. By studying Ceres' gravity, scientists learned more about the dwarf planet's internal structure and were able to determine that the brine reservoir is about 25 miles (40 kilometers) deep and hundreds of miles wide.

Ceres doesn't benefit from internal heating generated by gravitational interactions with a large planet, as is the case for some of the icy moons of the outer solar system. But the new research, which focuses on Ceres' 57-mile-wide (92-kilometer-wide) Occator Crater – home to the most extensive bright areas – confirms that Ceres is a water-rich world like these other icy bodies.

(Highlight from me)

 

[Astronuc]

A press release claiming "Ceres Was Formed In The Coldest Zone Of Our Solar System And The Thrusted Into The Asteroid Belt," was put out by São Paulo Research Foundation (FAPESP) within the last two days.
https://agencia.fapesp.br/dwarf-pla...r-system-and-thrust-into-asteroid-belt/38634/

The research was conducted by Rafael Ribeiro de Sousa, a professor in the program of graduate studies in physics on the Guaratinguetá campus. The co-authors of the article are Ernesto Vieira Neto, who was Ribeiro de Sousa's PhD thesis advisor, and researchers affiliated with Côte d'Azur University in France, Rice University in the United States, and the National Observatory in Rio de Janeiro.

The story has been picked up and reported by some media.

The paper is reported in Icarus, Volume 379, June 2022, 114933 (Elsevier)

Dynamical origin of the Dwarf Planet Ceres​

https://www.sciencedirect.com/science/article/abs/pii/S0019103522000549

I haven't read the paper yet, nor browsed the thread, but I'm curious about their conclusions and the observations reported.