A concept of the European Space Agency's ExoMars Rover. Credit: European Space Agency/AOES Medialab artist's concept

Scientists briefed on U.S. President Barack Obamaโ€™s proposed NASA budget say it would reduce funding for planetary science by $300 million next year with further cuts over the next five years, The Washington Post reports.

NASAโ€™s Mars exploration program would take a big hit under the plan, which severs the U.S. partnership with the European Space Agency on the ExoMars program to send probes to Mars in 2016 and 2018. โ€œThe impact of the cuts โ€ฆ will be to immediately terminate the Mars deal with the Europeans,โ€ G. Scott Hubbard, a Stanford University and former NASA planetary scientist, said. โ€œItโ€™s a scientific tragedy and a national embarrassment.โ€

U.S. Rep. John Abney Culberson (R-Texas) said the Obama cuts โ€œabsolutely will not flyโ€ with the House committee that oversees NASA. โ€œYou donโ€™t cut spending for critical scientific research endeavors that have immeasurable benefit to the nation and inspire the human spirit of exploration we all have,โ€ Culberson said.

The budget is set to be released Feb. 13.