Updates Dawn Mission News

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NASA JPL: It's Complicated: Dawn Spurs Rewrite of Vesta's Story

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Click on images for details​

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This image shows infrared views of two craters at the giant asteroid Vesta that NASA's Dawn mission has found to sport the mineral olivine.
Image credit: NASA/JPL-Caltech/UCLA/ASI/INAF​
|This colorized map from NASA's Dawn mission shows the types of rocks and minerals distributed around the surface of the giant asteroid Vesta.|In this contrast-enhanced infrared image of Bellicia Crater on the giant asteroid Vesta, scientists from NASA's Dawn mission can see signs of the mineral olivine.
Image credit: NASA/JPL-Caltech/UCLA/ASI/INAF​
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On December 21, Dawn will be equidistant from Vesta and Ceres. The article also includes how Dawn will operate on two reaction wheels in a hybrid mode, or even fewer.

"Dawn Journal: Equidistant from Vesta and Ceres"

It is currently [eventTimer]2013-12-27 00:00:00?before|after;%d% day(s) %c%[/eventTimer] Dawn is ~0.21 AU from both asteroids.
 

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Dawn abruptly stopped thrusting and entered safe mode due to a single particle of ionizing radiation on 11 September. This unimaginably tiny particle had the ability to delay the spacecraft's arrival at Ceres by one month. The anomaly was compounded by potentially another particle that affected the spacecraft's computer, resulting in Dawn being unable to adequately point its high-gain antenna until the issue was resolved. Pretty crazy.

JPL: "Dawn Operating Normally After Safe Mode Triggered"
The Dawn spacecraft has resumed normal ion thrusting after the thrusting unexpectedly stopped and the spacecraft entered safe mode on September 11. That anomaly occurred shortly before a planned communication with NASA's Deep Space Network that morning. The spacecraft was not performing any special activities at the time.

Engineers immediately began working to restore the spacecraft to its normal operational state. The team determined the source of the problems, corrected them, and then resumed normal ion thrusting on Monday night, Sept. 15.

"This anomaly presented the team with an intricate and elaborate puzzle to solve," said Robert Mase, Dawn project manager at NASA's Jet Propulsion Laboratory in Pasadena, California.

After investigating what caused the spacecraft to enter safe mode, the Dawn team determined that it was likely triggered by the same phenomenon that affected Dawn three years ago on approach to the protoplanet Vesta: An electrical component in the ion propulsion system was disabled by a high-energy particle of radiation.

"We followed the same strategy that we implemented three years ago to recover from a similar radiation strike -- to swap to one of the other ion engines and a different electronic controller so we could resume thrusting quickly," said Dawn Mission Director and Chief Engineer Marc Rayman of JPL. "We have a plan in place to revive this disabled component later this year."

Complicating the issue, the team discovered that the spacecraft had experienced not just one anomaly, but also a second one that affected the ability to point the main antenna at Earth to communicate. Because the spacecraft could not communicate using its main antenna, the team had to utilize the weaker signals of another antenna, slowing their progress. In addition, Dawn is so far from Earth that radio signals take 53 minutes to make the round trip. Although they have not yet specifically pinpointed the cause of this issue, it could also be explained by a high-energy particle corrupting the software running in the main computer. Ultimately the team reset the computer, which restored the pointing performance to normal.

As a result of the change in the thrust plan, Dawn will enter into orbit around dwarf planet Ceres in April 2015, about a month later than previously planned. The plans for exploring Ceres once the spacecraft is in orbit, however, are not affected.

Dawn orbited Vesta, the second most massive object in the main asteroid belt, from July 2011 until September 2012. The spacecraft's ion propulsion system enabled it to spiral away from Vesta and head toward Ceres, the most massive object in that region. Thanks to the power of ion propulsion, Dawn is the only mission ever targeted to orbit two deep-space destinations.

[...]
 

RonDVouz

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Dawn abruptly stopped thrusting and entered safe mode due to a single particle of ionizing radiation on 11 September.
It was a TERRORIST PARTICLE!!

But that is sad though, I'm so looking forward to seeing the Ceres images. Well, waited this long, might as well wait another month.
 

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The first spacecraft that will explore a dwarf planet has a new trajectory after its incident in September.


Each dot on the trajectory represents an Earth day. The spacecraft will be captured by Ceres' embrace only a few hours after what was planned for the original trajectory. However, falling, and thrusting, into Ceres orbit will now take much longer as illustrated. Dawn will enter its initial high, circular orbit called RC3 by April 23. The spacecraft will obtain "detail more than 20 times finer" (Marc Rayman) than Hubble in this orbit. For a more detailed explanation, read the chief engineer's latest post in his fantastic blog.

There's one more thing that makes this update necessary: "Dawn Snaps Its Best-Yet Image of Dwarf Planet Ceres".


Seeing nine pixels of Ceres isn't that impressive, but Dawn's finally getting there! That photo was taken at a distance of only 1.2 million kilometers (or three times Earth's distance to the Moon) for calibrating the camera. There's still months to go due to the slow, but efficient, nature of ion propulsion.

---------- Post added at 04:10 AM ---------- Previous post was at 04:03 AM ----------

I can now add a new countdown clock, so why not?

It is [eventTimer]2015-03-06 00:00:00?until|since;%d% day(s) %c%[/eventTimer] capture by Ceres' gravity and [eventTimer]2015-04-23 00:00:00?before|after;%d% day(s) %c%[/eventTimer] the start of RC3 orbit.
 

fsci123

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When do we get some cool images?
 

fsci123

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For those who wanted to see the original image a week late:
 

fsci123

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This claimed to be the best image yet... It was compiled from images taken on the 25th.


Oh wow look at the ridges and craters.:hailprobe:

Behold the original:
 
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For more information (it would be nice if you could post a link), check the Dawn Mission website.

Dawn Mission: "NASA's Dawn Spacecraft Captures Best-Ever View of Dwarf Planet"
January 27, 2015—NASA's Dawn spacecraft has returned the sharpest images ever seen of the dwarf planet Ceres. The images were taken 147,000 miles (237,000 kilometers) from Ceres on Jan. 25, and represent a new milestone for a spacecraft that soon will become the first human-made probe to visit a dwarf planet. .

"We know so little about our vast solar system, but thanks to economical missions like Dawn, those mysteries are being solved," said Jim Green, Planetary Science Division Director at NASA Headquarters in Washington.

At 43 pixels wide, the new images are more than 30 percent higher in resolution than those taken by NASA's Hubble Space Telescope in 2003 and 2004 at a distance of over 150 million miles (about 241 million kilometers). The resolution is higher because Dawn is traveling through the solar system to Ceres, while Hubble remains fixed in Earth orbit. The new Dawn images come on the heels of initial navigation images taken Jan. 13 that reveal a white spot on the dwarf planet and the suggestion of craters. Hubble images also had glimpsed a white spot on the dwarf planet, but its nature is still unknown.

[...]
Emily Lakdawalla processed the animation differently (L) and made a comparison to the views from January 13 (R).


At the present resolution, Ceres (L) looks pretty similar to Umbriel (R):


As of this post, there are 36 days until Dawn is captured by Ceres. The spacecraft will enter its first targeted orbit, called RC3, in April. The animation below simulates Dawn and its view of Ceres from RC3.
 

statickid

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Id like to know why Ceres looks so much like Umbriel
 

fsci123

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I think the white spot could be a geyser.
 

Kyle

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IMO, I think it's a fresh impact crater. Aristarchus on Luna comes to mind.
 

statickid

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If that were true, could you mine the ice ? :hmm:

---------- Post added at 10:12 PM ---------- Previous post was at 09:58 PM ----------

Its probably just bright colored compared to the dust, not glinting necessarily. If Ceres is one of those super dark objects, even a medium grey could look brilliant
 
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