Our SpaceFlight Heritage: 50 Years since the launch of Ranger 9
On March 21, 1965, Ranger 9 was launched from Launch Complex 12 at the Cape Canaveral Air Force Station. It was carried aloft by the Atlas Launch Vehicle 3 and boosted out of Earth orbit by an Agena B booster. Ranger 9 was developed and operated by NASA’s Jet Propulsion Laboratory (JPL). Its purpose was to obtain high resolution photographs of the lunar surface and impact in the Alphonsus crater to determine if it could support the weight of a spacecraft.
The Ranger Program was among the first attempts made by the United States to explore another body in space: the Moon. Originally designed in 1959, the Ranger probes were split into three distinct phases or blocks.
Block 1 consisted of Rangers 1 and 2, which were placed into a lower Earth orbit than planned resulting in premature re-entry.
Block 2, consisting of Rangers 3-5, was the first attempts to impact the Moon, but the probes were all unsuccessful and ended up in deep space.
The Block 3 probes consisted of Rangers 6-9. Ranger 6’s cameras failed though it had an otherwise flawless flight. Ranger 7-9 were successful, with Ranger 8 helping to determine the first manned lunar landing site.
Ranger 9 was the last mission of the Ranger Program. Ranger 9 was unique because it carried six television vidicon cameras providing millions of Americans on Earth a live broadcast of its final 19 minutes of flight until impact. Along with the television cameras, Ranger 9 carried two full scan cameras and four partial scan cameras. There were no other scientific instruments on board.
On March 24, with 19 minutes of flight left, Ranger 9’s cameras were turned on and oriented in the direction of travel to ensure the best pictures. The first picture was taken at an altitude of 1,468 miles (2,363 km).
Five minutes before impact, pictures showed channels, called rilles, in the Alphonsus crater. The final picture was taken 2/10 of a second prior to impact at an altitude of 1/3 mile (540 m) above the crater with a stunning resolution of 0.98 feet (0.3 m). Ranger 9’s final velocity before impact was 1.66 miles per second (2.67 Km/sec).
During a later press conference, the photos taken were shown to the press as a continuous motion movie. Just before the impact, Astronaut Wally Schirra, who was in attendance, shouted out, “Bail out you fool!” – much to the amusement of the audience.
A total of 5,814 good contrast photos were taken during the 19 minute descent. The photos, along with photos taken by other Ranger spacecraft, were used to determine future landing sites for the Surveyor Lunar Landers.
Gregory N. Cecil is the only Florida State Certified Educator and Nationally Certified Aerospace Technician in the nation. He holds a Masters in Aeronautical Science: Space Operations Management from Embry-Riddle Aeronautical University and worked on the Space Shuttle Program. He is a science teacher and has taught in both public and private schools. Gregory has written over 50 articles relating to the space program and continues to contribute to the promotion of space.