The Mars rover has been temporarily shut down to prevent damage from a large solar flare.
On Tuesday, a huge stream of plasma shot out from the Sun and travelled 141,610,495 miles across space in the direction of the Red Planet.
Nasa scientists powered down Curiosity after noticing the flare, which they fear could damage active circuitry on the robot.
Writing on his blog, University of Leicester Mars scientist Dr John Bridges, who is part of the $2.5 billion Nasa mission, said: "On March 5 there was a large solar flare or Coronal Mass Ejection.
"This sent out a stream of plasma from the Sun - which has now reached Mars.
"The radiation associated with this could damage active circuitry so Curiosity has been kept in a low activity mode.
"Data from our Radiation Asssessment Detector (RAD) instrument will help document the intensity of this solar storm."
Dr Bridges said Mars' thin atmosphere and lack of a magnetic field means that it is more susceptible to solar radiation.
He said: "When Mars did have a magnetic dipole, like the Earth has today, the surface of Mars would have been more protected from solar radiation. That's part of the reason many researchers think microbial life might have been possible at that time."
The shut down will mean a delay in analysing the rock dust Curiosity recently collected from the planet's surface.
Curiosity also had a computer problem at the start of the month which meant it had to be put into 'safe mode' following a memory glitch. It is now back in 'active status'.
