For the first time, I was SOWG Chair for a 2-sol planning session on Saturday. Earlier this month, the MSL project stopped scheduling tactical operations on Sundays, to give the team a break once a week. So we've been planning 2 sols at a time on Saturdays, which can be challenging, but it went pretty well this time. The focus continues to be on Chemin and SAM analysis of the first drill sample, and we look forward to hearing the results of these analyses soon. We were also able to add a few DAN and Mastcam observations, again limited by battery power.

Planning was more difficult today because of power limitations. The top priority for Sol 196 is to drop some of the drill sample into SAM and analyze it overnight. SAM is the largest instrument on MSL, and it requires lots of power to run. As usual, the tactical science team proposed some additional observations, but it quickly became apparent that they would not fit into the plan. Even after making the difficult decision to remove them during the SOWG meeting, we still didn't have enough power. Fortunately, we got an updated power prediction late in the meeting that was more favorable--based on analysis of the latest telemetry from the rover, it became clear that the initial estimate of the battery charge at the beginning of Sol 196 was too low. The change in the power prediction allowed us to keep all of the SAM activities in the plan!

After taking a break from tactical operations for an MSL science team meeting (and a bit of vacation) last week, I'm back on as SOWG chair for Sol 195 planning. The most exciting part of this plan is "feeding" some of the first drill sample to Chemin. There wasn't much room to add additional science observations to the plan, but we were able to squeeze in a couple of ChemCam LIBS activities. We can't wait to see what Chemin will tell us about the minerals in the drill sample!

I was happy to see that first drill sample was successfully acquired on Sol 182, as shown in one of the MAHLI images I helped plan . The whole team is very excited about this news!

The "mini-drill" test went well , so Sol 182 planning focused on the first full drilling activity. As MAHLI/MARDI uplink lead again, I concentrated on planning MAHLI images of the drill target, to be taken both before and after the drilling. A lot of effort had already gone into planning these images, so I spent most of my time helping to ensure that the planned durations of these imaging activities were correct and would fit into the available time. We also had to tweak the downlink priority of some of the images to ensure that the data needed to assess the results of the drilling will be received in time to plan the next sol.

Planning is still "restricted," so we had an opportunity to acquire more ChemCam and imaging data on Sol 181 while waiting for confirmation that the Sol 180 "mini-drill" test completed successfully. As MAHLI/MARDI uplink lead, I focused on planning MAHLI images of 3 targets in front of the rover. We had to avoid the area of the drill testing, to avoid disturbing it, but there are plenty of other areas of interest. Again, the planning assumes that the Sol 181 activities went well, because we won't receive the Sol 181 data until early tomorrow morning.

Because the "drill-on-rock checkout" activity did not complete successfully on Sol 174, the MSL team had to work extra hard to determine how best to recover from the anomaly. Several engineers worked overnight in the rover testbed at JPL to understand the root cause of the problem in time to allow the tactical planning team to repeat the drill checkout on Sol 176 with only a minor change. Because this repeat affects what was tentatively planned for the next few sols, we had to quickly revise the long-term plan and consider how much power is needed in future sols before finalizing the Sol 176 plan. So it was a hectic day as SOWG Chair, but we were all glad the recovery was so quick.

As SOWG Chair again, I worked hard today to fit as many observations into the Sol 175 plan as possible while leaving enough energy in the batteries for Sol 176 activities. Overnight SAM analysis of a blank cell in preparation for a drill sample takes a lot of power, but we were still able to plan lots of additional MAHLI imaging during the day. We had almost finished reviewing and polishing the sequences when the latest data from the rover were received, including some bad news: there was an anomaly during the arm activities on Sol 174. It was too late in the day to make the major changes in the Sol 175 plan needed to respond to this anomaly, so we had to quit work on the Sol 175 plan and let the rover execute the "runout" plan that is routinely included in every day's set of commands. The runout consists of a few simple, safe activities--very different from the complex plan we developed today. While this was disappointing, the rover is safe and will likely recover quickly. When planning is "restricted" as it was today, because Mars and Earth time our out of sync, we have to accept the risk that we will not receive data from the rover in time to respond to it.

I served as SOWG Chair for Sol 174 planning, which includes the first use of the drill on Mars. Drill tailings will not be collected during this test, which will use only the percussion (not rotation) drilling mode . MAHLI images will be taken before and after the drill activity, so the effect of the percussion on the outcrop target should be easy to assess. To enable SAM analysis of one of the "blank" samples brought from Earth on Sol 175, the Sol 174 plan has to leave the rover batteries nearly fully charged at the time of handover to the Sol 175 plan. This didn't leave much room for activities in addition to the drill test, but we were able to squeeze in ChemCam, DAN, Mastcam, and REMS observations.

Preparations for the first drilling activities continue to go well. The focus of the Sol 170 and 171 plans was to test the ability of arm to press the drill against the surface. Four targets were selected for the "preload" testing, and the arm was left pressed against one of them overnight, to see how the pressure changed with temperature. I was MAHLI uplink lead over the weekend, and helped plan images of the 4 targets before and after the preload tests. The goal of these images is to look at changes in the surface caused by pushing the drill against it.