Surveyor 4 is the fourth lunar lander in the American uncrewed Surveyor program sent to explore the surface of the

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

. This

spacecraft A spacecraft is a vehicle that is designed spaceflight, to fly and operate in outer space. Spacecraft are used for a variety of purposes, including Telecommunications, communications, Earth observation satellite, Earth observation, Weather s ...

crashed after an otherwise flawless mission;

telemetry Telemetry is the in situ collection of measurements or other data at remote points and their automatic transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Greek roots ''tele'', 'far off', an ...

contact was lost 2.5 minutes before touchdown. The planned landing target was

Sinus Medii Sinus Medii (Latin ''sinus mediī'' "Middle Bay") is a small lunar mare. It takes its name from its location at the intersection of the Moon's equator and prime meridian; as seen from the Earth, this feature is located in the central part of the ...

(Central Bay) at 0.4° north latitude and 1.33° west longitude. Surveyor 6 successfully landed near the crash site of Surveyor 4 a few months later in November 1967.

Equipment

This spacecraft was the fourth in a series designed to achieve a soft landing on the Moon and to return

photography Photography is the visual arts, art, application, and practice of creating images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is empl ...

of the lunar surface for determining characteristics of the lunar terrain for

Apollo Apollo is one of the Twelve Olympians, Olympian deities in Ancient Greek religion, ancient Greek and Ancient Roman religion, Roman religion and Greek mythology, Greek and Roman mythology. Apollo has been recognized as a god of archery, mu ...

lunar landing missions. Equipment on board included a television

camera A camera is an instrument used to capture and store images and videos, either digitally via an electronic image sensor, or chemically via a light-sensitive material such as photographic film. As a pivotal technology in the fields of photograp ...

and auxiliary mirrors, a soil mechanics surface sampler,

strain gauge A strain gauge (also spelled strain gage) is a device used to measure Deformation (mechanics)#Strain, strain on an object. Invented by Edward E. Simmons and Arthur C. Ruge in 1938, the most common type of strain gauge consists of an Electrical in ...

s on the spacecraft landing legs, and numerous engineering sensors. Like Surveyor 3, Surveyor 4 was also equipped with a surface claw (with a magnet in the claw) to detect and measure ferrous elements in the lunar surface. After a flawless flight to the Moon,

radio Radio is the technology of communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connec ...

signals from the spacecraft ceased during the terminal-descent phase at 02:03 UT on July 17, 1967, approximately 2.5 minutes before touchdown. Contact with the spacecraft was never reestablished, and the mission was unsuccessful. The solid-fuel retrorocket may have exploded near the end of its scheduled burn.

References

External links

Surveyor Program Results (PDF) 1969
4 Spacecraft launched in 1967 Spacecraft launched by Atlas-Centaur rockets Spacecraft that impacted the Moon Missions to the Moon 1967 on the Moon {{US-spacecraft-stub

Equipment

See also

References

External links