DAWN mission to orbit 1 Ceres & 4 Vesta.

3488 · Sep 17, 2007

I would love to see a sample return from 1 Ceres too. A nice deep core sample will do. <img src="/images/icons/laugh.gif" /> As you say, the 12% solar constant is quite nice too, solar power will work, but the panels unless of the low temperature & / or concentrator GaAs type, will have to be quite large. 1 Ceres at the equator can briefly get to a toasty minus 38 Celsius / 235 Kelvin, with the Sun at zenith. This is even warmer than many areas in our own polar regions. <img src="/images/icons/crazy.gif" /> At night though, it is a different story. That why I would like a RTG powered lander that can work all of the time, day & night on 1 Ceres. DAWN, will answer the question about the albedo & colour variations, due to liquid water reacting with Fe rich clays. Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

h2ouniverse · Sep 17, 2007

Also: The frost line is similar for H2O and NH3. So Ceres should have accumulated a significant quantity of ammonia. With a gentle cooling from the outside, the ammonia should concentrate progressively in the subsurface ocean up to about 32%. Then the freezing temperature is minimal and the water+ammonia mix will freeze altogether, stopping the water versus ammonia differentiation. But... max temperature on Ceres is about 235K on surface. That is pretty high. Far above freezing point of a 32% ammonia-enriched water (177K)... The average temperature is about 160, 170K at surface. And higher on the equator... So if there has been 32%ammonia-water local upflows from ocean to surface, you might find areas close to surface where the liquidus line is crossed. That is the particularity of Ceres, formed outside the frost line, but now way beneath. regards.

3488 · Sep 17, 2007

I suspect the orbit of 1 Ceres has not changed much, but the Sun was only about 70% as powerful in its youth, than it is now, enough to move the 'frost line' outward. I see what you mean about the H20 / NH3 mix. Do you think there might be geysers of the stuff along the equator & tropics about 6 degrees north / south? The surface temperatures may allow for that. Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

h2ouniverse · Sep 18, 2007

Hi Andrew. Why not? Logically the surface clays shoud cover all that but let's see when Dawn is there. The initial average ratio NH3/H20 should be about 7% (Solar System average N vs O abundancies). To reach 32% of ratio, this means a concentration by a factor 4.5. So a 100km-deep initial ocean would have to freeze up to 78% of thickness to concentrate ammonia up to 32%. The point is that the higher the NH3 ratio, the lower the density (0.887). Slightly before this point the ocean density becomes lower than pure water ice density, meaning that the ice shelf should tend to sink, be submitted to huge stresses. Hence logically cracks and opportunities for the ammonia mix to surge up. Also at 170K, water ice vaporizes. I would suspect that interesting phenomena should occur. For instance: 1) a block of frozen 32%-ammonia-water mix lies under a thin clay layer at the surface 2) temperature reaches 177K at noon, H2ONH3 ice melts. 3) part of it is vaporized, bubbling through clay 4) temperature cools down (at night!) below 160K, H2O and NH3 vapors recondense, more or less mixed 5) dawn on Ceres observed by Dawn at Ceres: temperature rises again... Best regards.

MeteorWayne · Sep 20, 2007

Not big news, but I'll take any right now <img src="/images/icons/smile.gif" /> "09.20.07 Workers successfuly installed the payload fairing over the Dawn spacecraft on the top of the Delta II rokcet at Launch Pad 17-B on Thursday. The fairing protects the spacecraft from high temperatures during the early section of launch. It falls away in two pieces once the rocket reaches high into the atmosphere and friction decreases." <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

3488 · Sep 20, 2007

Cheers MeteorWayne. That is good news. Launch preparations are going extremely smoothly. <img src="/images/icons/laugh.gif" /> Fairing being installed around the DAWN Spacecraft. Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

MeteorWayne · Sep 20, 2007

Yes, I guess at this point, no news is good news <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

3488 · Sep 22, 2007

Hi MeteorWayne, Fancy trying this??? DAWN Spacecraft to appear to pass close to Pleiades / M45 two hours after launch. Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

alokmohan · Sep 23, 2007

Has it been launched?

cbased · Sep 23, 2007

it will be launched (hopefully!) on the 26th of September

MeteorWayne · Sep 23, 2007

Doesn't help us much Andrew <img src="/images/icons/smile.gif" /> Actually the Pleiades and I have become good friends this month as it has been close to the center of my field of view for meteor observing the whole of September <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

alokmohan · Sep 23, 2007

We wait for three days.

bpcooper · Sep 23, 2007

Launch has been postponed to Thursday, Sept. 27 at 7:20am. Weather has prevented fuel loading on the second stage again (already a day late this week). <div class="Discussion_UserSignature"> -Ben </div>

3488 · Sep 23, 2007

Cheers Ben, lets hope that there are no more delays. Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

JonClarke · Sep 23, 2007

You will behave yourelf sir, with those 7 sisters! <img src="/images/icons/smile.gif" /> Jon <div class="Discussion_UserSignature"> Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars Arthur Clarke </div>

MeteorWayne · Sep 23, 2007

I pleiades innocent to whatever I'm bein' accused of, officer. Just cause I look at them all night long....I;ve never touched them, honest!! <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

holmec · Sep 24, 2007

<blockquote>In reply to:<hr />I pleiades innocent to whatever I'm bein' accused of, officer. Just cause I look at them all night long....I;ve never touched them, honest!! <hr /></blockquote> Too funny! LOL <img src="/images/icons/laugh.gif" /> My wife says "That's cute". <div class="Discussion_UserSignature"> "SCE to AUX" - John Aaron, curiosity pays off </div>

MeteorWayne · Sep 24, 2007

So are they <img src="/images/icons/wink.gif" /> <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

MeteorWayne · Sep 24, 2007

Official postponement announcement; thanx BPCooper for the early heads up. MW 09.24.07 Katherine Trinidad Headquarters, Washington 202-358-3749 katherine.trinidad@nasa.gov George Diller Kennedy Space Center, Fla. 321-867-2468 george.h.diller@nasa.gov MEDIA ADVISORY: M07-121 NASA POSTPONES DAWN SPACECRAFT LAUNCH CAPE CANAVERAL, Fla. - The launch of NASA's Dawn spacecraft aboard a United Launch Alliance Delta II rocket has been postponed 24 hours. Fueling of the launch vehicle's second stage was unable to be completed on Sunday because of weather conditions at the launch pad. The launch now is scheduled for Thursday, Sept. 27, at the opening of a window that extends from 7:20 a.m. to 7:49 a.m. EDT. For reporters planning to establish remote cameras at the launch pad, set up has been rescheduled and will take place at 9 a.m. on Wednesday, Sept. 26. The prelaunch news conference is scheduled for 1 p.m., Tuesday, Sept. 25. Live launch coverage on NASA Television is set to begin Thursday at 5:15 a.m. For NASA TV streaming video, scheduling and downlink information, visit: http://www.nasa.gov/ntv For more information about Dawn, visit: http://www.nasa.gov/dawn <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

MeteorWayne · Sep 24, 2007

Apparently, the delayed propellant loading is now underway, so the Thursday morning launch looks good. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

alokmohan · Sep 25, 2007

The launch of NASA's Dawn spacecraft aboard a United Launch Alliance Delta II rocket has been postponed 24 hours. Fueling of the launch vehicle's second stage was unable to be completed on Sunday because of weather conditions at the launch pad. The launch now is scheduled for Thursday, Sept. 27, at the opening of a window that extends from 7:20 a.m. to 7:49 a.m. EDT. For reporters planning to establish remote cameras at the launch pad, set up has been rescheduled and will take place at 9 a.m. on Wednesday, Sept. 26. http://www.spaceref.com/news/viewpr.nl.html?pid=23586

alokmohan · Sep 25, 2007

Jugglery of word?Congrats.

3488 · Sep 25, 2007

Thank you very much MeteorWayne & alokmohan. Two very good pieces of news there. Looks like the new scheduling has worked. Of course I understand the risks posed by lightning very well & NASA made the correct decision to delay. The safety of the DELTA engineers comes first, as it should always. This is very good news indeed. <img src="/images/icons/laugh.gif" /> Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

MeteorWayne · Sep 25, 2007

Just a reminder, less than an hour till the pre launch news conference. The prelaunch news conference is scheduled for 1 p.m., Tuesday, Sept. 25. Live launch coverage on NASA Television is set to begin Thursday at 5:15 a.m. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

MeteorWayne · Sep 25, 2007

Live on NASA TV Now <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

DAWN mission to orbit 1 Ceres & 4 Vesta.

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