Surveyor 4

Surveyor 4
	Surveyor model on Earth
Mission type	Lunar lander
Operator	NASA
COSPAR ID	1967-068A
SATCAT no.	02875
Mission duration	62 hrs. 9 min. 1 sec. (launch to last contact)
Spacecraft properties
Manufacturer	Hughes Aircraft
Launch mass	1,039 kg
Dry mass	283 kilograms (624 lb)
Start of mission
Launch date	July 14, 1967, 11:53:29 UTC
Rocket	Atlas LV-3C Centaur-D
Launch site	Cape Canaveral LC-36A
End of mission
Last contact	July 17, 1967, 02:02:30 UTC (approx)
Lunar impact (failed landing)
Impact date	July 17, 1967, 02:05:00 UTC
Impact site	0°27′N 1°23′W / 0.45°N 1.39°W
	Surveyor ← Surveyor 3 Surveyor 5 →

Surveyor 4 was the fourth lunar lander in the American uncrewed Surveyor program sent to explore the surface of the Moon. This spacecraft crashed after an otherwise flawless mission; telemetry contact was lost 2.5 minutes before touchdown. The planned landing target was Sinus Medii (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 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. 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.^{[citation needed]}

After a flawless flight to the Moon, radio 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.^[3]