Note: I am posting my old blog entries from elsewhere on the internet. This entry was originally posted on 8/28/08
This will be my last dispatch from Mars Phoenix; I have finished my last shift as a member of the uplink team. We have reached Sol 90 and the end of the main mission and reached full mission success, completing the measurements that we promised NASA we’d do. Since we have a working spacecraft, NASA has funded an extended mission to allow work to continue, and the team is slowly returning to their home institutions. From here on out, Phoenix is in “remote operations” which means that everything is done through remotely logging into computers and communicating over phone conferences and through special internet chat rooms.
We’ve also converted over to Earth time, which has its own unique set of challenges – sometimes, the schedules are such that we are building the instructions for activities before the last list of instructions has even been run on Mars yet. This means that we don’t know if everything has worked when putting together a plan. For example, at one point we found out that the robotic arm had generated an error while digging and gone into safe mode two days before, and the commands we’d sent up the previous day were not going to be run. This makes planning our intricate observations – digging trenches, scooping samples, delivering samples to instruments, and running the instruments – very complicated. On the other hand, the team gets to live on the same schedules as our families and return to our homes, which is a big psychological relief.
In the last few weeks, we have finally seen the sun set in the martian arctic. The days will be getting shorter and the temperatures dropping as we head towards martian winter, and at some point Phoenix will get too cold to continue operating. It will probably not survive the martian winter. Already, frost has started to condense on the ground in the early morning, as you can see from the white stuff in this image.
We’ve been digging a third trench, which is about 18 centimeters deep currently. It is in between two of the polygons that characterize the plain we have landed on. Our two previous trenches have been dug on the polygons, and we have reached ice within the upper 5 or so centimeters, but we have not yet reached any ice in the new one. The robotic arm team is hoping to beat the Viking lander for deepest trench dug on Mars – Viking made it to about 20 cm. Phoenix is capable of digging to 50 cm depth, if everything cooperates. Here is an image of one of the dump piles from a trench.
Both TEGA, the ovens that heat up samples and analyze the gases released, and MECA wet chemistry laboratory (WCL), the beakers that dissolve soils and analyze their chemistry, have work left to do in the extended mission. TEGA is working through an analysis, and WCL is waiting for the scoop on the robotic arm to get a good sample into the next beaker.
Another portion of MECA, the atomic force microscope (AFM), has finally gotten going. AFM is a very delicate sort of instrument. It contains a little needle on a spring, and the needle is run back and forth across a martian dust particle. This gives us the shape of the particle, which can tell us about the history of the particle. We use AFM in conjunction with the optical microscope (OM) to look at the dust grains and particles in the soil. Here is an OM image of some dust, with an AFM closeup on a portion. These are the highest resolution images ever from another planet; the particle in the yellow circle is one millionth of a meter across.
To complete the update from MECA, here’s a picture of the final component, the Thermal and Electrical Conductivity Probe (TECP), the portion that I have been sending commands to all summer, shortly after analyzing soil properties. As with many other instruments on the lander, we’re still looking through the data we’ve gathered and thinking about what it means.
I hope you all enjoyed my updates, and will keep an eye out for future press releases from Phoenix. While the mission continues on as long as there is enough power (and funding from NASA HQ), I will be moving over to work on sequencing operations for Cassini, which is exploring Saturn and its moons and rings.
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