The absence of a Russian scientific instrument on board NASA's new Mars rover, scheduled for launch in 2020, should not be linked to political reasons; the instrument simply did not pass the competition, Lev Zeleny, chief of the Institute of Space Research at the Russian Academy of Sciences, said on Sunday.

"If you take part in the contest, it does not mean that you will definitely win. Several applications were submitted, ours was not chosen. I would prefer not to connect this to politics," Zeleny told reporters during the COSPAR Scientific Assembly in Moscow.

"To insist that our instrument must have been chosen, it is necessary to compare it with other participants of the contest. Internal competition was very strong," he added.

Zeleny specified that the Russian scientific instrument was created for neutron measurements and is a modification of Russian DAN instrument currently onboard NASA's Curiosity rover.

Earlier this week, NASA unveiled the winners of the science instrument competition to fly aboard the Mars 2020 rover.

According to Michael Meyer, lead scientist for the Mars Exploration Program, managed by NASA the new rover will be equipped with more upgraded hardware including lasers and ground-penetrating radar. Its main mission is to search for evidence of past life on the Red Planet.

He added that the development of the seven selected projects will cost about $130 million.