Tomorrow is a big day for Curiosity, because JPL's engineering team can start checking out the Mars Science Laboratory's instruments, having finished loading Curiosity's surface-optimized software over the last 4 sols.

Over the past few sols, JPL painstakingly reprogrammed both of its CPUs' radiation-hardened, electrically erasable programmable read-only memory, or EEPROMs, with new operating systems, testing each one carefully to make sure nothing went awry. The software was uploaded to Curiosity en route to Mars, so it's been waiting for the initial post-landing instrument checkouts to be completed.

We're well into Curiosity's Characterization Activity Phase (CAP), the month-long process of testing each part of the rover. Now comes the instrument checkout with the new software. Curiosity's instruments will each be turned on to make sure that data comes back looking the way it should. The Alpha-particle X-ray spectrometer (APXS) and Dynamic Albedo of Neutrons (DAN) instrument will both be powered up—APXS for a second, 20-minute test, DAN for the first time. DAN has an active and passive mode. In active mode DAN is capable of firing neutrons, but for now DAN will only be tried in passive mode. The Chemistry and Mineralogy (CheMin) X-ray diffraction and X-ray fluorescence instrument will get a checkout as well. Curiosity's radiation assessment detector (RAD) was already powered up shortly after landing.

A few images from Curiosity's memory have been downloaded over the last few days, despite the fact that no new science has been done yet. JPL would like to empty Curiosity's camera memory and make room for more pictures. The image below, looking southeast toward Mt. Sharp, shows mesas and buttes in the foothills, with artificially colored patches of sand in the foreground lying atop basalt rock. The mountain itself, the central peak of Gale Crater, is unfortunately cut off. These pictures were programmed before Curiosity actually arrived; new ones will be taken in a few sols to show the peak.

In addition to what's come out of Curiosity's post-landing checkout, there was a strip of images downloaded from the Mars Reconnaissance Orbiter's HiRISE camera. These images have been better-centered on Curiosity's location now that we know more accurately where Curiosity is. This image is just the top of a long strip that wouldn't fit in this article; clicking on it will take you to the entire image, well worth seeing.

JPL's Ashwin Vasavada pointed out a series of new overall firsts for the Mars Science Laboratory mission: the first-ever panorama of Gale Crater, the first measurements of high energy radiation on another planet, the first movie of a spacecraft landing on another planet, the first images from a focusable camera on another planet, first images of an ancient Martian river channel. Those Martian river channels were first spotted by Mariner in 1971; we've waited 41 years to see them close-up.

During the Tuesday press conference, JPL's MSL avionics chief engineer Jim Donaldson quoted Alfred North Whitehead, who once wrote, "Civilization advances by extending the number of important operations which we can perform without thinking about them." He was talking about the evolution of thought that was necessitated within JPL by the design of the rover's electronics. Curiosity has roughly 1.2 million logic gates arrayed over several Field Programmable Gate Arrays. JPL engineers who had worked on the roughly 20,000 gates apiece for Cassini and the Mars Exploration Rovers were initially bulldozed by the size of the job for Curiosity, which required new management practices, new tools, new thinking and ultimately more engineers. Eventually, although the probe was delayed, JPL was able to rise to the challenge.

One new capability Curiosity has, a "dream mode," allows the rover to do several things while it's sleeping. In its sleep, Curiosity can turn heaters on and off, monitor vehicle health and in general prepare for the next sol's activity. The new mode allows things to take place in a way that keeps most systems quiescent and saves power for the next sol.

On Sol 13, a few sols from now, JPL will relay commands to turn each one of the rover's wheels in place. When that's done, two sols later, Curiosity will take its first drive, advancing a few meters, turning to reverse so that it avoids backing into unseen territory, and then moving back to its original spot.

Shortly after that, Curiosity will have about a two-week window to do science before the engineering team reclaims the rover for a few more days to finish instrument checkout and test the arm. The rover will begin moving toward Mt. Sharp and ascend through the clay and sulphate layers at its base. The science team will be forced to choose one of six paths that have been identified through the buttes.

Or maybe not.

A few hundred meters in the wrong direction, Curiosity seems to have landed next to some alluvial fans that suggest water flow. This kind of dilemma was completely expected by the MSL science team; they knew they'd see things once Curiosity landed that would force them to consider, and reconsider, roads not taken.