Surveyor 4

Surveyor 4

Surveyor model on Earth
Operator	NASA
Major contractors	Hughes Aircraft
Mission type	Lander
Launch date	July 14, 1967 11:53:29 UTC
Launch vehicle	Atlas-Centaur
Mission duration	65 hours
Orbital decay	Impacted on moon July 17, 1967, 02:05:00 UTC at 0.45°N 1.39°W / 0.45; -1.39
COSPAR ID	1967-068A
Mass	282 kg after fuel used

Surveyor 4 was the fourth lunar lander in the American unmanned Surveyor program sent to explore the surface of the Moon.

• Launched July 14, 1967; landed July 17, 1967
• Weight on landing: 625 lb (283 kg)

This spacecraft crashed after an otherwise flawless mission; telemetry contact was lost 2.5 minutes before touchdown.

This spacecraft was the fourth in a series designed to achieve a soft landing on the moon and to return photography of the lunar surface for determining characteristics of the lunar terrain for Apollo lunar landing missions. Equipment on board included a television camera and auxiliary mirrors, a soil mechanics surface sampler, strain gauges on the spacecraft landing legs, and numerous engineering sensors. After a flawless flight to the moon, radio signals from the spacecraft ceased during the terminal-descent phase, approximately 2.5 min. before touchdown. Contact with the spacecraft was never reestablished, and the mission was unsuccessful. The solid fuel retro rocket may have exploded near the end of its scheduled burn.

Like Surveyor 3, Surveyor 4 was equipped with a surface claw (with a magnet in the claw) to detect and measure ferrous elements in the lunar surface. The mission was completely successful until all communications were abruptly lost 2 seconds prior to retrorocket cutoff at 02:03 UT on 17 July 1967, with only 2.5 minutes left to landing on the Moon. The landing target was Sinus Medii (Central Bay) at 0.4° north latitude and 1.33° west longitude. NASA concluded that the lander might have exploded when contact was lost.

External links

• Surveyor Program Results (PDF) 1969