Nature: The European Space Agency (ESA) has begun negotiations with Russia for a rocket to launch the first stage of ExoMars, in 2016, in exchange for Russian participation in the mission. The first stage of the mission will carry an orbiter designed to find possible sources of methane and other trace gases that could indicate the presence of microbial life on Mars. The orbiter would serve as a data relay for a rover, launched in 2018, that would collect Martian soil samples. A separate mission would carry those samples back to Earth for study. NASA officials had initially promised an Atlas V rocket for the 2016 launch, but they informed ESA earlier this year that budget problems would prevent them from doing so. They still intend to provide a rocket for the mission’s second stage in 2018.
The Week in Physics" is likely a reference to the regular updates or summaries of new physics research, such as those found in publications like Physics Today from AIP Publishing or on news aggregators like Phys.org.