NASA this week will attempt to land a rover on mars, and the engineers behind the mission say seven months of space travel will come down to what they call "seven minutes of terror."
That's the amount of time the rover, dubbed "Perseverance", will take to descend through the thin martian atmosphere to the surface of the red planet.
But its radio signals take eleven minutes to reach the Jet Propulsion Laboratory near los angeles, which means for those seven minutes, NASA won't know if the robotic astrobiology lab landed safely in one piece or burned to a crisp.
Al Chen, head of the JPL descent and landing team, called the entry, descent and landing phase the most critical and most dangerous part of the $2.7 billion mission.
Much is riding on the outcome. Building on discoveries of nearly 20 U.S. outings to Mars, Perseverance may set the stage for scientists to conclusively show whether life has existed beyond Earth, while paving the way for eventual human missions to the fourth planet from the sun.
Touchdown is currently scheduled for Thursday afternoon.