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Emily Lakdawalla • Jul 26, 2008

Phoenix Sol 60 rasping and dumping successful -- but we don't yet know if it got inside TEGA

EDIT: Now we know that there wasn't enough sample delivered to TEGA -- see the next post.

Snow White after the sol 60 rasping

NASA / JPL / UA / Texas A & M / color composite by Emily Lakdawalla

Snow White after the sol 60 rasping
On sol 60, Phoenix rasped a four-by-four array of holes into the flat floor of the Snow White trench, then dragged the scoop bucket across the array to collect as much sample as possible for delivery to TEGA.
Robotic arm scoop poised over TEGA oven 0, sol 60

NASA / JPL / UA

Robotic arm scoop poised over TEGA oven 0, sol 60
On sol 60 at 07:36 local solar time, the robotic arm scoop was poised over TEGA oven 0 with a bucket of soil rasped from the hard surface of the Snow White trench.
Delivery of an ice-rich soil sample to TEGA oven 0, sol 60

NASA / JPL / UA / MPI / animation by Emily Lakdawalla

Delivery of an ice-rich soil sample to TEGA oven 0, sol 60
On sol 60, Phoenix finally went through the multi-step operation to rasp a sample of ice-rich soil from the Snow White trench and deliver the shavings to the waiting oven 0 of the TEGA instrument. This animation documents the scoop poised over the oven, followed by its delivery, and then several more images of the oven taken over the course of the subsequent morning. A small pile of soil at the lower left corner of the open oven shrinks over the course of the morning, either because the shaking of the oven shifted the pile downward or because the pile contained icy material that sublimated, or both.

I am not quite sure why the many images of the oven over the course of the day were taken. There seem to be two possible reasons: one is that the oven may have been repeatedly vibrated, once per hour or so, to make sure any sample got through the screen. But that doesn't seem very likely, because of their concerns about how fast the ice in the raspings might sublimate. The more likely interpretation is that the images were taken to document what happened to any of the sample that remained on top of the screen. In this zoomed-in view of the animation you can see that the little pile at the lower left corner diminishes in size over the course of the day. So maybe that's sublimation happening. But then again, maybe it isn't, because the little piles of soil on the adjacent (oven 1) doors don't seem to be diminishing in size. So maybe the diminishing pile is the result of further shaking after all. I plan to wait and see what the official announcements are on TEGA status from the mission, then I'll ask those questions.

Post-sample-delivery animation of TEGA oven 0, sol 60

NASA / JPL / UA / MPI / animation by Emily Lakdawalla

Post-sample-delivery animation of TEGA oven 0, sol 60
On sol 60, Phoenix finally went through the multi-step operation to rasp a sample of ice-rich soil from the Snow White trench and deliver the shavings to the waiting oven 0 of the TEGA instrument. This animation looks at a small area around the open oven 0, enlarged by a factor of two, after the delivery. A small pile of soil at the lower left corner of the open oven shrinks over the course of the morning, either because the shaking of the oven shifted the pile downward or because the pile contained icy material that sublimated, or both.

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