NASA intends to cancel plans for the U.S. to join Europe on a Mars sampling mission that is considered important to learning if life appeared beyond Earth.
The U.S. space agency is facing budgetary constraints, with $17.7 billion budgeted for 2013, about the same as this year.
NASA's cancellation leaves the European Space Agency without a key partner for a proposed two-spacecraft mission to collect and return soil samples from Mars.
The so-called Exobiology on Mars, or ExoMars, probes had been scheduled to launch in 2016 and 2018.
Compiled from agency reports