Question about the Phoenix Lander Landing

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CometPhoenix

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If the ice on the landing site is about 4-6 centimeters thick, and the shuttle is going to be very hot from the entry, what's to stop it from sinking through the ice? <div class="Discussion_UserSignature"> <font color="#0000ff"><p style="margin-top:0in;margin-left:0in;margin-right:0in" class="MsoNormal"><font face="Times New Roman" size="3" color="#0000ff">What ever happens, happens/</font><font face="Times New Roman"><font color="#0000ff"><font size="3">Just call me Phoenix</font></font></font></p></font> </div>
 
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MeteorWayne

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>If the ice on the landing site is about 4-6 centimeters thick, and the shuttle is going to be very hot from the entry, what's to stop it from sinking through the ice? <br />Posted by CometPhoenix</DIV><br /><br />This question should really go in the Phoenix thread in Missions and Launches.</p><p>Briefly (since you should move the question to that thread), the landing thrusters will only be near the surface for a few seconds. The craft is falling at 5 km/hr. So there will be some dust&nbsp; kicked up. Planning for that, they delay the solar panel deployment for 20 minutes or so.</p><p>MW</p> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>
 
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CometPhoenix

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If the ice on the landing site is about 4-6 centimeters thick, and the shuttle is going to be very hot from the entry, what's to stop it from sinking through the ice? <div class="Discussion_UserSignature"> <font color="#0000ff"><p style="margin-top:0in;margin-left:0in;margin-right:0in" class="MsoNormal"><font face="Times New Roman" size="3" color="#0000ff">What ever happens, happens/</font><font face="Times New Roman"><font color="#0000ff"><font size="3">Just call me Phoenix</font></font></font></p></font> </div>
 
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Philotas

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Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>If the ice on the landing site is about 4-6 centimeters thick, and the shuttle is going to be very hot from the entry, what's to stop it from sinking through the ice? <br />Posted by CometPhoenix</DIV><br /><br />It's not going to be very hot, the heat shield is shading it from all the entry heat that is generated. <div class="Discussion_UserSignature"> </div>
 
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centsworth_II

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<p>The ice is below the surface.&nbsp; </p><p>Phoenix must first dig through a layer of soil, perhaps 4-6 centimeters thick, to get to the ice.&nbsp; </p> <div class="Discussion_UserSignature"> </div>
 
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qso1

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<p><font color="#800080">If the ice on the landing site is about 4-6 centimeters thick, and the shuttle is going to be very hot from the entry, what's to stop it from sinking through the ice? Posted by CometPhoenix</font></p><p>In addition to MeteorWaynes excellent comment, terminal descent would cool the vehicle as well. The hottest part of the entry is well above 100,000 feet. The slower parachute descent lasts longer allowing for some cooling to occur.&nbsp;</p> <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
 
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DrRocket

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>If the ice on the landing site is about 4-6 centimeters thick, and the shuttle is going to be very hot from the entry, what's to stop it from sinking through the ice? Posted by CometPhoenixIn addition to MeteorWaynes excellent comment, terminal descent would cool the vehicle as well. The hottest part of the entry is well above 100,000 feet. The slower parachute descent lasts longer allowing for some cooling to occur.&nbsp; <br />Posted by qso1</DIV></p><p>What you say is true.&nbsp; In addition the heat shields reach a high temperature, but that temperature is on the surface and the back of the shield is cool.&nbsp; It is necessary that this be so in order to do its job.&nbsp; If I understood the sequence of events for landing, that hot heat shield is jettisoned some time prior to touchdown.&nbsp; So the Phoenix probe itself should be relatively cool.</p> <div class="Discussion_UserSignature"> </div>
 
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derekmcd

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It should also be mentioned that the heat shield was a cork-like material that ablated as it heated up... shedding the hot stuff to keep the rest of it cool so to say.<br /> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>
 
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centsworth_II

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<font color="#666699"><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>If the ice on the landing site is about 4-6 centimeters thick...<br /> Posted by CometPhoenix</DIV></font><br />There is no ice on the surface of the landing site.&nbsp; The ice is several centimeters below the surface. <div class="Discussion_UserSignature"> </div>
 
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willpittenger

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>There is no ice on the surface of the landing site.&nbsp; The ice is several centimeters below the surface.</p><p>Posted by centsworth_II</DIV><br /><br />With a catch: We already know the thrusters cleared down to the ice &mdash; or at least something that looks like ice. </p> <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>
 
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primordial

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Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>With a catch: We already know the thrusters cleared down to the ice &mdash; or at least something that looks like ice. <br />Posted by willpittenger</DIV><br /><br />Look are deceiving, and it's possible it could be CO2.
 
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centsworth_II

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<font color="#666699"><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Look are deceiving, and it's possible it could be CO2. <br /> Posted by primordial</DIV></font><br />The scientists, who have orbital data showing much water in the area have made no mention of the possibility of CO2 ice.&nbsp; The possibilities seem to be between water ice and rock, with the visual evidence favoring ice.&nbsp; Of course there should be a lot of soil mixed in with the ice.&nbsp; The question is, how much? <div class="Discussion_UserSignature"> </div>
 
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3488

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'><font color="#ff0000">The scientists, who have orbital data showing much water in the area have made no mention of the possibility of CO2 ice.&nbsp; The possibilities seem to be between water ice and rock, with the visual evidence favoring ice.&nbsp; Of course there should be a lot of soil mixed in with the ice.&nbsp; The question is, how much? <br />Posted by centsworth_II</font></DIV></p><p><strong><font size="2">Also it is currently too warm for dry ice. From late Autumn to approx the Spring Equinox, it will be cold enough, but at this time of the Martian year, it is too warm. -30 C maximum at the moment. During Winter, the Phoenix site will drop to approx -135 C, plenty cold enough for CO2 ice.</font></strong></p><p><strong><font size="2">Andrew Brown.</font></strong><br /></p> <div class="Discussion_UserSignature"> <p><font color="#000080">"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".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>
 
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willpittenger

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Also it is currently too warm for dry ice. From late Autumn to approx the Spring Equinox, it will be cold enough, but at this time of the Martian year, it is too warm. -30 C maximum at the moment. During Winter, the Phoenix site will drop to approx -135 C, plenty cold enough for CO2 ice.Andrew Brown.</p><p>Posted by 3488</DIV><br />In that case, it will be nice to see what the last pictures returned by MPL2 are. </p> <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>
 
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3488

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'><font color="#ff0000">In that case, it will be nice to see what the last pictures returned by MPL2 are. <br />Posted by willpittenger</font></DIV></p><p><strong><font size="2">It will be. I really hope that Phoenix lasts well into January 2009, after the Autumn Equinox, though it will be getting much darker&nbsp;& colder very quickly. </font></strong></p><p><strong><font size="2">I suspect that is only a pipe dream. It will very interesting to see the final images whenever they will be,</font></strong></p><p><strong><font size="2">Andrew Brown.</font></strong></p> <div class="Discussion_UserSignature"> <p><font color="#000080">"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".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>
 
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jasonpply

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<p>it's salt deposits under the lander i think. if water on mars was as salty as they think it may have been wouldnt it be really hard to freeze without seperating the salt from the water?</p><p>&nbsp;</p>
 
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3488

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'><font color="#ff0000">it's salt deposits under the lander i think. if water on mars was as salty as they think it may have been wouldnt it be really hard to freeze without seperating the salt from the water?&nbsp; <br />Posted by jasonpply</font></DIV></p><p><font size="2"><strong><font color="#000000">I&nbsp;really hope it's ice, though</font> evidence may now be stearing away from that given the latest Optical Microscope images (see Phoenix Surface mission thread in M&L).</strong></font></p><p><font size="2"><strong>We cannot say for 100% sure until the readings are back from the TEGA.</strong></font></p><p><font size="2"><strong>Marfs gets more than cold enough for even extremely saline water to freeze. Take the Phoenix site, late Winter / early Spring&nbsp;temperatures drop to about the -135 C / -211 F mark. That is pushing towards cryonic temperatures.<br /></strong></font><br /><strong><font size="2">Andrew Brown.</font></strong></p> <div class="Discussion_UserSignature"> <p><font color="#000080">"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".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>
 
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willpittenger

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Marfs</p><p>Posted by 3488</DIV><br />I think we have a new planet. <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-smile.gif" border="0" alt="Smile" title="Smile" /></p> <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>
 
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