The European Space Agency says it still hasn't received any signal from its experimental Mars lander since shortly before it was meant to reach the red planet's surface.

That means the planned "soft landing" of the Schiaparelli probe Wednesday likely failed, though there's no confirmation of that yet.

The head of ESA, Jan Woerner, said Thursday that the mission should still be considered a success because the probe sent a vast amount of data back before going silent.

He said the data will be used to plan a future European robotic mission to Mars planned for 2020.

Woerner said that the other part of the ExoMars mission, which involved putting a probe into the orbit of Mars to analyze gases in its atmosphere, worked exactly as planned.