The same approach is being taken in planning further exploration of Mars.

He has also contributed to plans for the human exploration of Mars.

The modern outlook on Mars exploration is not the same.

This is such a major change in our thinking about exploration of Mars.

For the robotic exploration of Mars, such programs are already under way.

Everything worked perfectly, and yet the effect was to discourage further exploration of Mars.

It included almost no new programs beyond his call for manned exploration of Mars.

The experience was especially frustrating because it had become an all too frequent part of Mars exploration.

As envisioned, the robotic exploration of Mars in the 1990's would cost up to $10 billion.

It will have only a slight effect on the exploration of Mars.