Surveyor 4
Surveyor 4 — a lander lost in the final moments (launched 14 July 1967). Its descent looked flawless until radio contact ceased about two and a half minutes before touchdown, probably a retrorocket failure; it was never heard from again. (Intended site, Sinus Medii, shown.)
Key facts
Mission & specifications
Mission
- Operator
- NASA / JPL
- Launched
- July 14, 1967
- Status
- Lost
Trajectory
- Distance from the Sun
- 1.01 AU
- Computed from the cached position
- Distance from Earth
- 0.867 AU
- Computed from cached positions
- Distance from Mercury
- 0.629 AU
- Computed from cached positions
Mission
Surveyor 4 was lost in the last moments of what had looked like a perfect flight. Launched on 14 July 1967, it flew a flawless trajectory to the Moon and began its terminal descent toward Sinus Medii. Then, about two and a half minutes before touchdown — with the retrorocket firing — all radio contact abruptly ceased. Nothing was ever heard from it again. The most likely explanation is that the solid retrorocket failed, perhaps exploding, and destroyed the spacecraft in the final seconds of descent. After three successes it was a stark loss, and a reminder of how unforgiving those last moments above the surface were.
Images
Images from open archives · credit shown per image