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welcome to the Phoenix spacecraft entry

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descent and landing simulation computer

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simulation of what we think will happen

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on Sunday May twenty-fifth 2008 a May

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twenty-fifth Phoenix will land near the

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North Pole of Mars Phoenix enters the

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atmosphere going over 12,000 miles per

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hour at a very grazing angle about 13

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degrees the very shallow angle allow us

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to take advantage of the very thin

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atmosphere of Mars to slow us down as

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much as we can before our parachute

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opens up this robotic vehicle is

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controlled by itself it has its own

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computer on board that controls all of

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the events that you see that take place

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in the simulation as the vehicle hits

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the top of the atmosphere it will start

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to warm the heat shield which protects

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the vehicle from this heat is an ablator

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an ablator is a heat shield that

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actually has material that leaves the

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heat shield that takes the heat away as

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the vehicle goes through the atmosphere

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without this ablator the vehicle would

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burn up in the atmosphere instead while

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the heat shield will get over a thousand

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degrees Celsius the inside of the

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vehicle never gets above room

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temperature as the vehicle enters the

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atmosphere the vehicle is transmitting

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what it's doing and where it is and what

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its orientation is to our orbiting

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spacecraft Mars Reconnaissance Orbiter

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and Mars Odyssey these vehicles have

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unfortunately all this hot gas that

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surrounds the vehicle prevents the

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signal from making it to our orbiters

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it's not until it slows down later on

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that the signal will actually make it

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out to the vehicles to let us know how

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it went as you can see on the displayed

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on the lower left there is a horizontal

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velocity indicator as well as a vertical

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velocity indicator on the left there is

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an altimeter tells you how high this

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vehicle is above the surface of Mars on

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the bottom is a profile of the

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trajectory the vehicles taking through

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the atmosphere of Mars on the lower

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right is our landing site you can see it

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its in green on the lower right there is

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a clock that tells us how many seconds

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to the next event in this case the next

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on the upper right is it the number of

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now that the plasma blackout has ended

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the signal can be more clearly seen from

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our vehicles that are flying overhead in

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the case of Odyssey Odyssey is taking

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these radio signals and relay them back

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to earth where 15 minutes later the

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signal arrived at the Deep Space Network

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and be interpreted by our team in the

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mission-control area here at JPL the

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next event is parachute deployment this

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is where we launch a cannon that

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launches the parachute into the free

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stream behind it now this inflation

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happens very quickly but quickly the

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parachute slows us down to about 120

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miles per hour under the control of the

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computer the heat shield is released it

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seconds later the three lander legs are

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released preparing itself for landing on

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the surface of mars phoenix landing site

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although very far to the north is

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actually very low relative to mars

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atmosphere for this reason this part of

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the entry descent landing timeline is

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much longer than it was for the two

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Rovers that landed in 2004 we span over

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two minutes falling on the parachute at

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very high speeds right now we're still

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over 150 miles per hour as we're

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at this point the radar has been turned

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on by the computer and the radar is

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searching for the ground it's sending a

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pulse to the ground and back up to the

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vehicle and from that pulse the vehicle

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is able to figure out how fast it's

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moving respect to the ground and how

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the parachute used by the Phoenix is the

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same parachute design used to land both

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the Viking missions in the 1970s as well

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as the Mars Exploration Rover missions

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2004

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once the vehicle is low enough to the

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ground the on-board computer decides if

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it's time to release the lander and let

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it fall away from the back shelf as soon

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as it does that its engines will start

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there are 12 pulsed engines after

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writing itself the first thing the

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lander does is move away from the back

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from the parachute so it doesn't make

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recontact during the descent and then

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very short period of time the vehicle

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will slow itself down and land a little

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as soon as we land the helium that

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pressurized a propulsion system during

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landing is vented this keeps the

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hydrazine from potentially leaking onto

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the surface of Mars 20 minutes later the

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solar panels are deployed these solar

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panels will provide the lead electricity

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to operate the vehicle that rest of the

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mission a few minutes after the solar

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rays are deployed the vehicle puts

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itself to sleep for about half an hour

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once it wakes up again camera will be

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deployed the bio barrier that covers the

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robotic arm will be released and the

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vehicle will start taking pictures of

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the solar panels and of the bio barrier

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a few minutes after that an orbiter

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flies overhead which will allow us to