DAWN mission to orbit 1 Ceres & 4 Vesta.

JonClarke · Nov 4, 2008

I think the surface of Ceres will be mostly to entirely rocky.  Maybe a few ice patches in shaded polar regions. For art, try Ron Miller's site http://www.black-cat-studios.com/catalog/asteroids.htmlJon <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>

3488 · Nov 4, 2008

Thank you very much Wayne.Yes I was aware that thrusting had been intenentially stopped as this is one of the 'coasting along' portions of her long trajectory.DAWN remains very healthy & is in full operational order. The Mars encounter in February will be the first major science that DAWN will return, approaching Mars from the nightside, departing the dayside, much like MESSENGER has with Mercury. DAWN will also shoot a sol long departure movie showing Mars rotating.DAWN will also be using the whole instrument suite to scan the forth rock from the Sun & the UV results will study the structure of the martian atmosphere in profile, much like the ESA Rosetta did to huge effect.Wonder if DAWN will image either or both of Phobos & Deimos?  Replying to: <DIV CLASS='Discussion_PostQuote'>I think the surface of Ceres will be mostly to entirely rocky.  Maybe a few ice patches in shaded polar regions. For art, try Ron Miller's site http://www.black-cat-studios.com/catalog/asteroids.htmlJon Posted by jonclarke</DIV>Yes, I think so too now Jon. 1 Ceres is well within the frost line now, so any ice will be as postulated for the Moon & Mercury, within permanently shadowed craters.Hopefully the HST after the STS 125 Atlantis mission will study 4 Vesta, 1 Ceres & 2 Pallas again with the new instruments prior to the 4 Vesta arrival.Wonder if either 1 Ceres or 4 Vesta actually have any moons?????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 · Nov 4, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Wonder if either 1 Ceres or 4 Vesta actually have any moons?????Andrew Brown.  Posted by 3488</DIV> IMHO, that seems unlikely considering what is being doscovered in the Kuiper belt. However, we could always be surprised

<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 · Nov 5, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>IMHO, that seems unlikely considering what is being doscovered in the Kuiper belt. However, we could always be surprised

Posted by MeteorWayne</DIV>I think you are correct Wayne, I just threw in a bone there. Some of the pipsqueeks found in the KB, like Eris's moon Dysnomia & Pluto's moons Nix & Hydra, amongst others like Orcus's & Quaoars's moons does lend credence to the fact that 1 Ceres & 4 Vesta are moonless, unless they are really tiny, but like yourself, I think there are none. 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 · Nov 5, 2008

I discovered that we have a eucrite in the basement rock collection at work.  I will try and dig it out tomorrow.  I won't say what else we have in the meteorite collection, for fear that Wayne will get jealous.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 · Nov 5, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I discovered that we have a eucrite in the basement rock collection at work.  I will try and dig it out tomorrow.  I won't say what else we have in the meteorite collection, for fear that Wayne will get jealous.Jon Posted by jonclarke</DIV> <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-laughing.gif" border="0" alt="Laughing" title="Laughing" /> <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>

JonClarke · Nov 5, 2008

Bits of Allende and Murchison, as well as several Pallasites and a mesosiderite.  I think they have a Diogenite as well.No lunar or martian ones though.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>

3488 · Nov 21, 2008

DAWN completes current phase of ION propulsion & is now on course with coasting to complete the Mars encounter next February.The Mars encounter is essential for DAWN to reach 4 Vesta in 2011, then 1 Ceres in 2015.Update here.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 · Dec 3, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>DAWN completes current phase of ION propulsion & is now on course with coasting to complete the Mars encounter next February.The Mars encounter is essential for DAWN to reach 4 Vesta in 2011, then 1 Ceres in 2015.Update here.Andrew Brown. Posted by 3488</DIV> Here's the Dawn Journal at TPS describing the events. I find their writing style a bit annoying, but there's a lot of good info in here is you wade through it... http://www.planetary.org/blog/article/00001755/ <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 · Dec 4, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Here's the Dawn Journal at TPS describing the events. I find their writing style a bit annoying, but there's a lot of good info in here is you wade through it... http://www.planetary.org/blog/article/00001755/ Posted by MeteorWayne</DIV>Thank you very much Wayne.I agree, that article is very long winded but does contain some fascinating information. The article was not written for the novice in mind, but then again Wayne, I think we are well above novice level, so we could understand it, but could put off a newcomer.I am really looking forward to the Mars encounter next February, as that will be the first major test of the instrumentation. Also the Mars departure movie showing Mars rotating as receding in colour should be pretty spectacular? Roll on both 4 Vesta & 1 Ceres though. This is one hell of a mission.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 · Jan 11, 2009

Daniel Muller has a realtime page for the Feb flyby of Mars..http://www.dmuller.net/realtime/index.php?mission=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>

Boris_Badenov · Jan 12, 2009

Replying to: <DIV CLASS='Discussion_PostQuote'>Daniel Muller has a realtime page for the Feb flyby of Mars..http://www.dmuller.net/realtime/index.php?mission=dawn Posted by MeteorWayne</DIV>Cool countdown page, thank you very much. How close will the Mars Flyby be? <div class="Discussion_UserSignature"> <div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div> </div>

MeteorWayne · Jan 12, 2009

Replying to: <DIV CLASS='Discussion_PostQuote'>Cool countdown page, thank you very much. How close will the Mars Flyby be? Posted by boris1961</DIV> Still looking for that info; in the meantime I found this, which I thought was interesting, from the Dawn FAQ:"Frequently asked questions:Question: I see that a gravitational trajectory assist is scheduled for February 2009 (angular momentum transfer) with Mars. Normally, outward-bound probes pass by the planet while closer to the sun than the planet. The Dawn probe seems to be further away from the sun than Mars, so it would be traveling faster than Mars before the transfer. Wouldn't that slow the probe down, instead of speeding it up with respect to the sun? A more succinct question would be: How much delta V are you expecting from the Mars encounter (heliocentric velocity). Answer: There is a wide range of geometries that can make planetary gravity assists effective, and while approaching from outside the orbit of the planet may appear unusual, Dawn is not unique in doing so. The specifics of the gravity assist include not only the relative speed between the probe and the planet but also the direction each one is moving at the time of the encounter.In our case, the principal benefit of the gravity assist is to change the plane of Dawn's orbit around the Sun. Based on your choice of words, you seem to have some understanding already of the key principles, so you probably already know that most planets orbit the Sun close to the plane of Earth's orbit, also known as the ecliptic. You may also know that changing the plane of an orbit can be energetically very expensive. Vesta and Ceres orbit farther from the ecliptic than most planets do.If we had launched in 2006, the ion propulsion system could have achieved the plane change by itself. The mission is a little more difficult with a 2007 launch, because there is less time to complete the required ion thrusting before the relative alignment of Vesta and Ceres makes the trip between them inconveniently long. Therefore, we take advantage of the gravity of Mars to change Dawn's inclination. The delta-v is about 1.1 km/s, providing a plane change of less than 5°, but that significantly reduces the time Dawn needs to thrust, allowing it to reach Vesta at about the same time, even after launching a year later." A related fact, Vesta orbits the sun at an inclination of 7.1 degrees, which is higher than any (full) planet in the solar system. <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>

dmuller_dot_net · Jan 12, 2009

Replying to: <DIV CLASS='Discussion_PostQuote'>How close will the Mars Flyby be? Posted by boris1961</DIV>I have seen 500km being mentioned as the flyby altitude, but not sure if that still applies (or if memory serves me right)

MeteorWayne · Jan 12, 2009

Replying to: <DIV CLASS='Discussion_PostQuote'>I have seen 500km being mentioned as the flyby altitude, but not sure if that still applies (or if memory serves me right) Posted by dmuller_dot_net</DIV> Thanx, and thanx VERY much for your countdown sites!!!We science geeks love it! <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>

h2ouniverse · Jan 12, 2009

hi all, could finally find these cool artist's views of potential Ceres surface http://arcadiastreet.com/cgvistas/ab_menu_ceres.htmbest regards.

dmuller_dot_net · Jan 14, 2009

According to the Dawn ops team, the best estimate of the closest approach to Mars is February 17 at 16:28:55 PST +/- 35 seconds (Spacecraft Event Time). They will continue to refine the time over the coming weeks, with the principal uncertainty being the effect of RCS activity to desaturate reaction wheels. Also there will be no high resolution images of Mars during closest approach, and no observations of Mars are possible whilst Dawn approaches Mars because the Sun is at too close an angle to Mars. After all, the Mars flyby is just a means to reach Vesta, and would not have been in the flight plan had the mission launched earlier.

3488 · Jan 14, 2009

Replying to: <DIV CLASS='Discussion_PostQuote'>According to the Dawn ops team, the best estim........................................ Posted by dmuller_dot_net</DIV>Hi dmuller_dot_net.Very big welcome to SDC & I really like your various countdown pages. I've copied over the link, buried pages ago in this thread, back in early October. Has some details of the upcoming Mars encounter.Details of DAWN Mars encounter in February 2009.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>

dmuller_dot_net · Jan 14, 2009

Replying to: <DIV CLASS='Discussion_PostQuote'>According to the Dawn ops team, the best estimate of the closest approach to Mars is February 17 at 16:28:55 PST +/- 35 seconds (Spacecraft Event Time). They will continue to refine the time over the coming weeks, with the principal uncertainty being the effect of RCS activity to desaturate reaction wheels. Also there will be no high resolution images of Mars during closest approach, and no observations of Mars are possible whilst Dawn approaches Mars because the Sun is at too close an angle to Mars. After all, the Mars flyby is just a means to reach Vesta, and would not have been in the flight plan had the mission launched earlier. Posted by dmuller_dot_net</DIV> The source of the above information was provided by Marc Rayman, Chief Engineer of the Dawn mission.

dmuller_dot_net · Jan 26, 2009

Update on the flyby distance. I have been uploading more accurate trajectory information into the Dawn simulation (http://www.dmuller.net/dawn), source from NAIF SPICE kernels, and they indicate a flyby altitude of 568km. And thanks 3488 for the very warm welcone! Daniel

dmuller_dot_net · Jan 30, 2009

Dawn trajectory update for Mars flyby. Closest approach now expected 18 Feb 00:29:03 UTC at 550km altitude. Source; SPICE kernels (update 29Jan)

3488 · Jan 30, 2009

Replying to: <DIV CLASS='Discussion_PostQuote'>Dawn trajectory update for Mars flyby. Closest approach now expected 18 Feb 00:29:03 UTC at 550km altitude. Source; SPICE kernels (update 29Jan) Posted by dmuller_dot_net</DIV>Hi dmuller. You can call me Andrew. Some members already do, they know who they are as they are great freinds on these boards. You too have joined them & please from now on, you can me Andrew.I love this mission to bits & was personally involved in the campaign to prevent DAWN's cancellation, one of three missions I got involved in helping to save from cancellation (Mars Phoenix Lander & New Horizons being the others).Next month we finally at long last, get to see what DAWN is actually capable of.Yes its true that there wll be no really high resolution views of Mars, Mars will be a slender crescent IIRC during the approach. IIRC for one sol post Periareion, DAWN will image Mars once every few minutes& create a movie of the forth rock from the sun rotating, as the Jupiter bound Galileo & Mercury bound MESSENGER spacecraft have with Earth. Then its only just two years & a half years to 4 Vesta (August 2011, only five months after MESSENGER brakes into orbit around Mercury), a fascinating giant basalt rich asteroid, third largest behind 1 Ceres & 2 Pallas. Is 4 Vesta an exposed core of a dwarf planet like 1 Ceres? DAWN will get to orbit both. This is one example of planetary science at it's very best. View of Mars post Periareion. <img src="http://sitelife.space.com/ver1.0/Content/images/store/2/5/f27da159-4410-4f78-a515-875616d4fa83.Medium.jpg" alt="" /> Jumping the gun here a bit, part of the 4 Vesta imaging campaign. <img src="http://sitelife.space.com/ver1.0/Content/images/store/8/9/88373f6d-743b-4f03-994e-5b598524e939.Medium.jpg" alt="" /> 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>

dmuller_dot_net · Feb 1, 2009

Make that 543 km altitude. The Dawn team uses a Mars radius of 3396km (I was using 3389.9) Replying to: <DIV CLASS='Discussion_PostQuote'>Dawn trajectory update for Mars flyby. Closest approach now expected 18 Feb 00:29:03 UTC at 550km altitude. Source; SPICE kernels (update 29Jan) Posted by dmuller_dot_net</DIV> Good on you Andrew for helping to save three of my favorite missions! I'm Daniel BTW

MeteorWayne · Feb 3, 2009

A New Dawn Journal entry:http://dawn.jpl.nasa.gov/mission/journal_1_27_09.aspExcerpts...When Dawn was fired into space, aiming for the window near Mars was analogous to shooting an arrow at a target 47 kilometers (29 miles) away. In the center of the target is a red circle 30 centimeters (almost 1 foot) in diameter, representing Mars. Of course, we don’t want our arrow to hit the red bull’s-eye! Rather, our goal is a spot about 2.2 centimeters (7/8 of an inch) outside the circle, near the 11:00 position.   By the time of TCM1 2 months ago, Dawn had traveled 880 million kilometers (550 million miles), corresponding to the arrow having sailed 39 kilometers (24 miles) from our bow. After flying that tremendous distance, our projectile was headed for the bull’s-eye itself, so we applied a tiny adjustment to put it on course for the real aim point.   By January 15, when the mission operations team had scheduled TCM2, Dawn had put more than another 110 million kilometers (70 million miles) behind it, so our arrow would have streaked another 5 kilometers (3 miles) closer to its target. Even with so far still to go, the aim is so good that no further correction is needed.   Although controllers will continue to monitor Dawn’s trajectory and refine the predictions of its course, as long as the arrow flies true, it will reach its target. With the latest estimate, instead of hitting the mathematically optimal spot, it will strike less than 2 millimeters (a little over 1/16 of an inch) farther from the bull’s-eye. It won’t quite land at the 11:00 position, but it will be less than a third of the way to the tick mark just after the 11:00 marker, where the hour hand would be pointing at about 11:04. This is comfortably within Dawn’s allowance for accuracy.   These coordinates correspond to the spacecraft passing about 543 kilometers (337 miles) above the reddish surface of the planet rather than the original plan of 500 kilometers (311 miles). While that may seem like a large difference, the effect of a gravity assist largely depends on the distance from the center of a planet, not the surface. In that context, instead of passing about 3896 kilometers (2421 miles) from the center, Dawn will pass 3939 kilometers (2448 miles) from that reference location. (The arrow strikes 17.4 centimeters, or less than 6 7/8 inches, from the middle of the bull’s-eye rather than 17.2 centimeters, or 6 3/4 inches.) The mission easily could accommodate much larger deviations from the original plan.   And what does the difference mean for the overall journey to the asteroid belt? Dawn’s 4-month period of coasting between Mars and the resumption of ion thrusting will be shortened by about 4 days. As the spacecraft will thrust for most of the 2.5 years from Mars to Vesta, powering up the ion drive a few days earlier is virtually inconsequential.    ....The powerful tug exerted by the planet will bend Dawn’s path by about 78 degrees. To picture that angle, suppose Mars is a dot at the center of a clock, and Dawn flies toward it (or, more accurately, toward the required window very nearby) from the 12. If the planet had no gravity, the spacecraft would continue in a straight path, exiting the face of the clock by the 6. Instead, the probe takes a sharp turn at the center of the clock and heads out between the 3 and the 4. (This is not the same clock used in the discussion of solar conjunction in the previous log. Be sure to check out the full selection of celestial timepieces in your planet’s Dawn gift shop.) The deflection from Mars changes Dawn’s orbit around the Sun (as does thrusting with the ion propulsion system). To enter orbit around Vesta, Dawn needs to match its orbit around the Sun to the one that Vesta is in, and the Mars encounter is designed to help accomplish that, bringing Dawn’s plane into closer alignment with Vesta’s. (We saw in the previous log that part of the journey requires changing the plane of Dawn’s solar orbit.) The gravity of Mars will alter Dawn’s orbital plane by about 5.2 degrees, a seemingly modest angle. Yet, if it were up to the spacecraft to accomplish such a change on its own, it would require a velocity change of more than 2.3 kilometers/second (5200 miles/hour)......The changes to Dawn’s orbit come at the expense of Mars’s orbit. Just as when you throw a ball forward, you feel a “reaction” force backward, in pushing the spacecraft one way, Mars reacts by moving the other. Mars exerts a force on Dawn, but Dawn exerts an opposite force on Mars. As the planet’s mass is nearly 600 million million million times that of the spacecraft, the effect on our probe is far larger than on the fourth planet from the Sun. The cost of helping Dawn is that Mars will slow in its orbit enough that after 1 year, its position will be off by about the width of an atom. Adding up the growing deficit, it would take 180 million years for Mars to be out of position by 2.5 centimeters (1.0 inches). That is the cost, and, on behalf of Dawn and all who share in the eager anticipation of the mysteries it will reveal in the asteroid belt, we express our gratitude to Mars for its upcoming sacrifice! .....The control team’s best estimate now is that Dawn’s closest encounter with Mars will occur at about 4:28 pm PST on February 17.... If you have the time and interest, I suggest reading the whole blog entry. There's far more than what I excerpted, and is one of the most informative so far. <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 · Feb 3, 2009

Replying to: <DIV CLASS='Discussion_PostQuote'>A New Dawn Journal entry:http://dawn.jpl.nasa.gov/mission/journal_1_27_09.aspExcerpts...When Dawn was fired into space, aiming for the window near Mars was analogous to shooting an arrow at a target 47 kilometers....... Posted by MeteorWayne</DIV>Thank you very much Wayne,Periareion 00:28 UTC on Wednesday 18th February 2009. The first real test of DAWN's intruments since launch. Plus we still get some good science from this encounter.Wonder if DAWN is obtaining navigational images of Mars. Perhaps the phase angle is too high & that Mars appears too close to the Sun. 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>

DAWN mission to orbit 1 Ceres & 4 Vesta.

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