1.   And Jull conceded that the answer may not come until the next century when new robot missions to Mars bring rock samples back to Earth.

2.   NASA science director Ed Weiler said the robot missions to Mars would be pathfinders for sending people there.

3.   NASA science director Ed Weiler said the robot missions to Mars are pathfinders for sending people there.

4.   The Bush budget supports a more robust program of Mars exploration, but withdraws funds for robot missions to Pluto and the sun.

5.   The United States does plan to send more robot missions to asteroids and to eventually land a craft on a comet and bring back samples.