The latest issue of Aviation Week and Space Technology discusses the continuing travails of ExoMars. It's not clear whether the cooperative arrangement with NASA will bring the mission into line with the maximum budget set by the ESA member nations. In addition, if NASA supplies the entry and descent system (where NASA has real expertise), then the development of this technology as an ESA expertise will not occur. This was one of the selling points of ExoMars, which is funded under the technology development program. A final problem is the the new arrangement with NASA could upset the distribution of contracts among member nations.
The issues are being worked and it appears too soon to put ExoMars on the critical care list. However, the head of ESA is quoted as saying that cancellation is a possibility and that a proposal must be ready by September 1 and ratified by the end of the year.
Editorial Thoughts: The exo-biological exploration of Mars is proving to be expensive with the Mars Science Laboratory coming in at over $2B and ExoMars nearing $1.5B (with instruments paid for separately by member states). I personally think that these missions were proposed for the wrong time period. I believe that several more inexpensive rovers should have been landed first to verify which location(s) would be best for searching for complex organics. Imagine what the reaction will be if either or both missions land in places that look great from orbit but prove unsuitable on the ground. (This is a seperate from the possiblity that the landing sites may in fact prove to be excellent places to search for organics, but that the results prove to be negative.)
Another concern is that these are big, complex missions that stretch the capabilities of both space agencies. I think they should have been placed on the roadmap with several years of technology development before final design and assembly. The proven way to mitigate risk with big missions is to do a substantial portion of the development years before launch, not in the midst of design, manufacture, and testing. (If the Jupiter-Europa mission flies around 2020, it will have had almost 20 years of such study and development before launch. Admitedly, this long is overkill.) My other great fear for both missions has been that development was pushed too quickly and we end up with a technical failure that cripples the mission. I for one am more comfortable with MSL having been delayed two more years to 2011 so that testing can continue another two years.