I'm back at JPL, serving as SOWG Chair planning Sol 57. The mission continues to go very well, with recent drives executed nearly perfectly. The rover is now positioned near a windblown ripple that is the current target of both scientific and engineering study. As I mentioned previously, we have been looking for a relatively fine-grained soil patch to scoop into CHIMRA, the "Collection and Handling for Interior Martian Rock Analysis" subsystem. CHIMRA will be used to sieve and portion samples into the CheMin and SAM instruments for mineralogic and organic chemical analysis. But before such samples will be delivered, some Martian soil will be used to clean any terrestrial contamination from CHIMRA by passing it through the system. So today's plan included the first "scuff" by one of the rover wheels, intended to measure the depth of the ripple and determine whether it is safe to scoop it. To scuff, the left front wheel will be rolled over the ripple, then that wheel will be rotated while the other 5 wheels are held stationary. This should allow a cross-section of the ripple to be imaged, and the composition of the interior of the ripple to be examined. After the scuff is complete, the rover will move back to essentially its current position to allow the arm to be used to place the MAHLI and APXS instruments into the scuffed area.

I haven't been following the MSL mission for the last couple days, traveling back to Flagstaff to give a talk about Mars rovers for the Flagstaff Festival of Science today at Lowell Observatory. I've been giving talks for the Festival for about 10 years, starting with an overview of the Mars Exploration Rover mission (Spirit and Opportunity) before those rovers landed on Mars in 2004. So I started my talk today with a quick update on the Opportunity mission, which is still going strong and exploring new rock types . Then I turned to MSL, and ran out of time even though I left out one of the cool videos I planned to show. So there wasn't much time for questions, but enough to embarrassed by one about today's press release . I was so busy preparing for my talk that I hadn't seen the release, so I didn't know what it was about! Too bad, because it would been nice to have included in my presentation images of the outcrop that was the subject of the press conference. A few sols ago, we drove by an outcrop that was immediately recognized as conglomerate, a poorly-sorted sediment that is commonly formed in stream beds on Earth. This type of rock was expected by some to be found in this part of Gale crater, and images taken from orbit showed that the landing site is near the base of a large alluvial fan, likely formed by ancient streams.

Yet another good drive on Sol 49, leaving the rover right next to a windblown ripple (right of center) . It doesn't look like much, but it's the first one we've been close to so it was the target of ChemCam and Mastcam observations planned for Sol 50. We are currently searching for a larger ripple or windblown drift for the first use of MSL's scoop, and these observations should help us determine how suitable such a ripple would be for scooping. The goal is to find a fine-grained deposit that can be "fed" to the mechanism on the arm that will be used to crush and sort samples before they are delivered to the mineralogy and chemistry experiments inside the rover. Processing a sandy sample will not only test this mechanism, it will sweep out any terrestrial contamination still remaining in it. The entire rover was carefully cleaned before launch, but it is very difficult to remove all traces of Earth, so passing Martian soil through the mechanism will "clean" it out. Another drive was planned for Sol 50, after the ripple observations. The Geology Theme Group focused on post-drive imaging, working with the Rover Planners to get the images they need to plan the following drive. We planned full 360-degree Navcam and Mastcam panoramas from the new location, which should allow us to pick a good soil target for scooping. Only the Navcam (wide-angle) images will be received in time to be used for planning Sol 51 observations, so we will use those images to determine which of the Mastcam images should be sent to Earth right away. If we see a good ripple or fine-grained soil patch nearby, we will probably drive over to it and scoop it up.

Today I served as the leader of the Geology Science Theme Group, which was fun because I had never done it before. The Sol 48 drive set a new record for MSL: 42 meters! We also heard the good news that APXS acquired high-quality data in only 12 minutes, during the middle of the day when the instrument was warmer that preferred. We also enjoyed the new MAHLI images of " Jake Matijevic ". So there was a lot of applause during our kickoff meeting today. The Sol 49 plan included another drive toward Glenelg, so we added some Mastcam and ChemCam observations of targets near the rover before the drive. We also planned Navcam and Mastcam panoramas after the drive, to document the area around the rover and allow more close-up observations on Sol 50.

"Mars time" is getting closer to PDT, with first shift starting around 6 AM today. Lots of good news and applause today: The Alpha Particle X-ray Spectrometer (APXS) received its first data from a Mars rock, the first MAHLI close-up images of the same rock , and the first mass spectrometer
measurement of the Martian atmosphere from SAM. But not all of the news was good...

I was SOWG Chair for Sol 47 planning, and was expecting an "easy" day for the science team because the long-anticipated arm activities had been planned well in advance and there would be no time in the plan for "opportunistic science." Well, that all changed quickly when we received the Sol 46 data that showed the ChemCam Remote Microscopic Imager (RMI) images all completely out of focus. The automatic focusing system had clearly failed, and successful focusing was required before the ChemCam laser could be fired at the same target today. So we had to scramble to recover from this anomaly and acquire ChemCam diagnostic data that would allow the engineering team to determine what had gone wrong. We were hoping to use ChemCam to measure the chemistry of the same spot on the rock "Jake Matijevic" that would be measured by the APXS before driving away on Sol 48, but it quickly became clear that this would not be possible. Instead, we decided to move the APXS spot to the place on the rock where ChemCam had previously acquired less extensive data. While not what we originally had in mind, it will allow us to proceed toward Glenelg as planned.

The Sol 45 rover "bump" was executed perfectly, putting the rover in position to deploy the arm instruments to the rock "Jake Matijevic" and shoot it with ChemCam's laser. So the Sol 46 plan includes the long-awaited first use of the arm on a rock target. I look forward to seeing the close-up MAHLI images of this rock.

I feel very luck to be working on the MSL project, and even luckier today that I got to see the space shuttle "Endeavor" fly right over JPL on a 747! It then landed at the LA airport, to be trucked to the California Science Center in Exposition Park where it will be permanently displayed.

The high-resolution color images of "Jake Matijevic" show that one face of the rock is clean (dust-free) enough for detailed study using the instruments on MSL's arm. So the Sol 45 plan includes a "bump" (short rover drive) to get close enough to reach it with the arm. We also planned ChemCam laser shots on the rock before the bump to see how much its chemistry varies on millimeter scales. After the drive, late afternoon images of Aeolis Mons (the huge mountain in the middle of Gale crater, informally known as Mt. Sharp) were planned. Previous images of Aeolis Mons were taken with the sun high in the sky, so that subtle topography is difficult to see. The new mosaic should be spectacular, but will take days to weeks to return to Earth because of the large volume of data involved.

Once again, the rover planners (drivers) displayed their ability to position MSL accurately, leaving the rover right where we wanted . It looks like the rock named "Jake Matijevic" will suffice for the first examination of Mars by the Alpha Particle X-ray Spectrometer (APXS) and close-up imaging by the Mars Hand Lens Imager (MAHLI). The Sol 44 plan included Mastcam color imaging of " Jake Matijevic" that will be used to decide whether this rock is suitable for the long-anticipated arm activities. The rock was named after a pioneering JPL robotics expert who played a major role in the development and operation of the Sojourner, Spirit, Opportunity, and MSL rovers. I am lucky to have known Jake; we met during preparations for the Mars
Pathfinder (and Sojourner) mission in the mid-1990s. His name is still posted outside his JPL office in the MSL operations area, and I'm sad every time I walk past it. He would have loved to see how well MSL is doing.

We all celebrated the Mastcam images of the Phobos transit . I've enjoyed astronomy since I was a child, but astronomical observations from the surface of Mars are a special treat! Similar observations have been made from the Spirt and Opportunity rovers, but the new Mastcam images have much higher resolution. Such observations are not top priority for Mars rovers, but opportunities to view Phobos and Deimos transits are rare enough that considerable effort it put in to planning them. Because the Opportunity rover is at about the same latitude as MSL (near the equator), observations of solar transits by the Martian satellites were also planned today by the Opportunity team.

A couple of transits of Mars' moon across the face of the sun were observed
by Mastcam. These are similar to solar eclipses on Earth, but because the
Martian moons are so much smaller than Earth's moon, they do not completely
block the sun. But they are still fun to watch and scientifically useful,
as they allow the position of the moons to be determined and their orbits
to be precisely updated. The rate of change of the moon's orbits is
affected by the interior structure of Mars, so in a way the transits are
geophysical observations.

I was SOWG Chair for Sol 43 planning, and I was busy because it was an
ambitious plan: ChemCam characterization in morning, followed by a ~30
meter drive toward a dark boulder that may become the target of close-up
investigation using the arm. On the morning of Sol 44, the rover will wake
up early to look for frost or fog before dawn, then take a big Mastcam
panorama toward the northwest while the lighting is good.

The Sol 41 drive went well, but we are still on relatively featureless
terrain. We planned another drive for Sol 42, and a huge Mastcam mosaic
from the new position. It is pointed toward Glenelg and the surrounding
area, and will be used to identify interesting targets for future
investigations.

Another first-time activity was completed on Sol 41: Active neutron
spectrometry during the drive. These data will allow variations in
hydrogen (most likely in hydrated, or water-rich minerals) within about 1
meter of the surface to be measured in greater detail. Such variations
have already been detected between the places the rover has stopped.

Our work schedule is getting closer to normal workday hours, with first
shift starting around 4 AM these days. By the end of September our
schedule will be close to that of most Earthlings in California!