Surveyor 4: Echoes from the Void
An exploration of NASA's ambitious lunar lander mission, its objectives, and the abrupt silence that marked its final moments.
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Mission Overview
Primary Objective
Surveyor 4 was the fourth robotic lunar lander in NASA's Surveyor program. Its primary objective was to achieve a soft landing on the Moon's surface and transmit photographic data and environmental readings back to Earth. This information was crucial for planning the crewed Apollo lunar landing missions, providing vital data on terrain characteristics and landing site suitability.
Target Landing Zone
The intended landing site for Surveyor 4 was Sinus Medii (Central Bay), a prominent mare region located near the Moon's equator. The specific coordinates targeted were approximately 0.45° North latitude and 1.39° West longitude, chosen for its relatively flat terrain and scientific interest.
Mission Timeline
The mission encompassed a total duration of approximately 62 hours, 9 minutes, and 1 second, from its launch until the final loss of contact. This period included the transit to the Moon, orbital insertion maneuvers, and the critical terminal descent phase.
Spacecraft Specifications
Manufacturer
The Surveyor 4 spacecraft was constructed by Hughes Aircraft, a key contractor for NASA's deep space programs during that era.
Mass and Dimensions
The lander had a total launch mass of approximately 1,037.4 kilograms. Its dry mass, excluding propellant and other consumables, was around 283 kilograms (624 pounds), making it a substantial piece of engineering for its time.
Launch Details
Launch Date and Time
Surveyor 4 was launched on July 14, 1967, at 11:53:29 UTC. This precise timing was critical for achieving the desired trajectory towards the Moon.
Launch Vehicle
The spacecraft was propelled into space by an Atlas LV-3C Centaur-D rocket, designated AC-11. This powerful launch vehicle was essential for delivering the heavy Surveyor probe on its translunar trajectory.
Launch Site
The launch originated from Cape Canaveral, Florida, specifically from Launch Complex 36A (LC-36A), a site historically significant for numerous American space missions.
The Critical Incident
Loss of Contact
During the crucial terminal-descent phase, approximately 2.5 minutes before its scheduled touchdown, all radio telemetry signals from Surveyor 4 abruptly ceased. This occurred around 02:03 UTC on July 17, 1967. Despite extensive efforts, contact with the spacecraft was never reestablished.
Potential Cause
The prevailing hypothesis for the sudden loss of communication suggests a catastrophic failure of the solid-fuel retrorocket during its final burn. An explosion or malfunction of this critical component would have instantly rendered the lander uncontrollable and likely led to its destruction or uncontrolled impact on the lunar surface.
Mission Outcome
As a direct consequence of the communication failure and presumed destruction, Surveyor 4's landing attempt was unsuccessful. The mission failed to achieve its primary objectives of a soft landing and surface data transmission, marking a significant setback for the Surveyor program.
Instrumentation and Objectives
Imaging System
Surveyor 4 was equipped with a sophisticated television camera and auxiliary mirrors. This system was designed to capture panoramic images of the lunar landscape, providing essential visual data for geological analysis and site assessment for future Apollo missions.
Surface Sampler
A key scientific instrument was the soil mechanics surface sampler, often referred to as a "scoop." This device was intended to analyze the composition and mechanical properties of the lunar regolith. Similar to Surveyor 3, it included a magnet within the claw to detect and measure ferrous elements in the lunar soil.
Engineering Sensors
The spacecraft was outfitted with numerous engineering sensors to monitor its performance during descent and on the surface. Strain gauges on the landing legs provided crucial data on touchdown forces and surface stability. These sensors were vital for understanding the dynamics of lunar landings.
Aftermath and Context
Impact Site and Follow-up
While the exact impact location is unknown due to the loss of telemetry, it is presumed that Surveyor 4 crashed in the vicinity of its intended landing zone in Sinus Medii. Notably, Surveyor 6, launched a few months later in November 1967, successfully landed near the crash site of Surveyor 4, providing valuable data that Surveyor 4 could not.
Verification Concerns
This article's content is derived from publicly available data. While efforts have been made to ensure accuracy, the original source material indicated a need for additional citations for verification. This highlights the importance of rigorous sourcing in scientific documentation.
Related Missions
Surveyor 4 was part of a larger program aimed at lunar exploration. Its predecessors, Surveyor 1, 2, and 3, provided foundational data, while its successors, Surveyor 5, 6, and 7, continued the mission's objectives, contributing significantly to the success of the Apollo program.
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References
References
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Disclaimer
Important Notice
This page has been generated by an AI and is intended for educational and informational purposes only. The content is based on data from Wikipedia and other sources, which may not be exhaustive, entirely accurate, or fully up-to-date. The original source material for Surveyor 4 indicated a need for additional citations, underscoring the dynamic nature of information verification.
This is not professional advice. The information provided does not constitute expert consultation on space mission planning, engineering, or historical analysis. Always consult official documentation and subject matter experts for critical applications or research.
The creators of this page are not responsible for any errors or omissions, or for any actions taken based on the information provided herein.