The European Space Agency says it will attempt to land the first spacecraft on a comet on Nov. 12.
It says the maneuver will take about seven hours starting from the moment its unmanned probe Rosetta releases the 100-kilogram lander at 0835 GMT (0335 EST).
Because of the 28 minutes it takes the signal to travel back to Earth, confirmation of a successful landing won't arrive until about shortly after 1600 GMT (1100 EST).
ESA said in a statement Friday that it has a backup plan in case of a problem with the preferred landing site.
Scientists hope the decade-long mission to examine comet 67P/Churyumov-Gerasimenko will help them learn more about the origins and evolution of objects in the universe.