- Mariner 3: Mars flyby attempt. Solar
panels did not open, preventing flyby. Mariner
- 3 is now in a solar orbit.
- Mariner 8: It failed to reach Earth
orbit.
- Mars Observer: Communication was
lost with Mars Observer on August 21, 1993,
- just before it was to be inserted into Mars orbit. It
was believed that Mars Observer developed a major leak in its propulsion
system, sending it out of control.
