NAPLES, Italy — Russian export control procedures made it impossible for Europe’s ExoMars mission in 2016 to employ a Russian nuclear heater that would have permitted the ExoMars lander to operate for two years on the martian surface, the ExoMars prime contractor said Oct. 3.

Instead of functioning as a ground-based weather monitor for a full martian year, the European-built lander will be limited to providing data as it parachutes to the Mars surface and then for around four martian days — eight Earth days — until its batteries deplete.

In what they described as a Russian regulatory regime that resembles the U.S. ITAR — International Traffic in Arms Regulations — ExoMars managers have been forced to return to their original lander design.

In separate briefings at the 63rd International Astronautical Congress in Naples, Italy, ExoMars prime contractor Thales Alenia Space and Italian Space Agency President Enrico Saggese said scrapping the 100-watt Russian radioisotope thermoelectric generator (RTG) has its positive aspects as well.

Saggese said ongoing concerns about the effects of the RTG’s steady release of heat during the 2016 voyage to Mars orbit would force a redesign of the mission to protect the telecommunications and trace gas orbiter, which is the main payload.

Saggese said Oct. 3 that eliminating the RTG also makes less complicated the 2016 mission’s construction in what already was a tight schedule. For example, the RTG would have been integrated into the entry, descent and landing package in Russia, not in Europe, in preparation for a launch aboard a Russian Proton rocket.

The Russian space agency, Roscosmos, is expected to confirm its participation in ExoMars by late November. ExoMars includes a 2018 launch of a European rover vehicle and a Russian-European entry, descent and landing package.

The Italian Space Agency is the biggest contributor to ExoMars, a European Space Agency mission that backers say appears to have found sufficient support to move forward on the 2016 and 2018 launches — assuming Roscosmos confirms its participation.

Vincenzo Giorgio, ExoMars project manager at Thales Alenia Space, said Russian authorities had signaled their willingness to provide the RTG for the 2016 mission pending final approval from Russia’s technology export authorities.

Giorgio said the European team already had redesigned the 2016 mission to protect the orbiter from the RTG-produced heat during flight. But Russian authorities subsequently informed the ExoMars team that final authorization would not arrive before next February — too late to meet the ExoMars 2016 schedule.

Giorgio agreed with Saggese that removing the RTG does help the 2016 mission keep to its schedule, but said the cost in terms of lost scientific return is high.

Peter B. de Selding was the Paris Bureau Chief for SpaceNews.