We've only sent a few dozen robot spacecraft to orbit Venus and even fewer landers.

It was the first robot spacecraft to successfully land on the Red Planet.

Water is crucial to plans for exploring Mars with robot spacecraft to find evidence of life, and for possible visits by humans.

But first, let's consider the visions of a hopeful future vouchsafed by robot spacecraft out among the planets.

No human lives are risked when a robot spacecraft is lost.

Antennas on the robot spacecraft were to be perfectly aligned with Earth for two or three days in mid-December.

In any case, our robot spacecraft, according to whatever built-in criteria it has, decides that this sphere is interesting.

A robot spacecraft swinging high over the earth's poles today began a search for the beginning of time.

The feat took unusually accurate navigation and clever use of the robot spacecraft's limited communications capability.

Von Braun had not foreseen the technological advances that would take place and the development of robot spacecraft.