Surveyor 5 is the fifth lunar lander of the American uncrewed Surveyor program sent to explore the surface of the Moon. Surveyor 5 landed on Mare Tranquillitatis in 1967. A total of 19,118 images were transmitted to Earth. The mission experienced a helium leak in the system that pressurized the liquid-fuel vernier engines that could have resulted in failure. An improvised landing sequence which started the retrorocket just 42 km above the Moon (about half the usual height) allowed the vernier engines to bring the craft down in 106 seconds from a height of only 1340 m (about 10% of the usual). This brought the craft down with a helium pressure on the edge of what would have shut the engines down from lack of pressure.

Wikipedia: https://en.wikipedia.org/wiki/Surveyor_5. Related NASA reference: https://science.nasa.gov/mission/surveyor-5/. Description adapted from Wikipedia contributors (CC BY-SA 4.0; https://creativecommons.org/licenses/by-sa/4.0/).