Keith's 3 Dec 10:33 am ET note: Consideration is being given to delaying the launch of NASA's Mars InSight lander mission. The problem has to do with the French seismometer. There is a persistent leak inside the seismometer that has been hard to fix. Given that this payload is one of the two prime functions of InSight if the issue is not resolved in the next month or so then the launch will be slipped until the next favorable Mars launch window opens. I am awaiting a formal statement from NASA PAO.
"A key science instrument that will be carried aboard NASA's Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport (InSight) spacecraft being prepared for launch in March 2016 is experiencing a leak in the vacuum container carrying its main sensors. The sensors are part of an instrument called the Seismic Experiment for Interior Structure (SEIS), which is provided by the French Space Agency (CNES)."
"Technicians have detected a small leak in the vacuum-sealed sphere that holds the instrument's three seismometers, NASAWatch reported and NASA confirmed on 3 December. The leak must be fixed for the mission to accomplish its science goals. CNES engineers are working to repair it before shipping the instrument to the Vandenberg Air Force Base in California to be installed in the spacecraft and tested."