Winston
Lorenzo von Matterhorn
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Apollo 12: Fifty years ago, a passionate scientist’s keen eye led to the first pinpoint landing on the Moon
November 12, 2019
https://theconversation.com/apollo-...the-first-pinpoint-landing-on-the-moon-126100
Excerpts:
When Apollo 11 landed on the Moon, it was a giant leap for mankind and a huge success for American engineering, but there was one aspect of the mission that hadn’t really gone as planned. When Neil Armstrong manually guided the lunar module to a safe touchdown, he had to override the computer which had the craft landing in a field of boulders. It left the demonstration of precision automated guidance to Apollo 12.
Fifty years ago this month, Apollo 12 successfully landed within a few hundred meters of its target, 400,000 kilometers (248,500 miles) away from where it lifted off. A key figure responsible for that precision landing was an unassuming Englishman living in the Arizona desert, Ewen Whitaker. Without the aid of computers or GPS, but with patience and an exhaustive knowledge of the geography of the Moon, Whitaker pinpointed where a robotic spacecraft had landed two years earlier.
When NASA’s Surveyor 1 became the first robotic spacecraft to perform a soft landing on the Moon, in 1966, Whitaker wasn’t officially part of the team. But when the team studied the images from Surveyor 1’s camera, and published the location where they thought they had landed, Whitaker disagreed. When he examined the images of the peaks and craters and compared them to the highest-resolution images of the Moon’s surface available, he concluded the spacecraft was actually a few kilometers away from the published location. The team agreed.
NASA had landed the Surveyor 3 unmanned craft in 1967, and the location had several advantages for an Apollo 12 landing site. It was clearly an area where a spacecraft could safely land; it was near the equator, which made it easily accessible. And, if the landing was close enough to Surveyor 3, the astronauts could walk over and remove pieces of it to bring back to Earth. That way, scientists could study the wear and tear on the materials after spending two years on the lunar surface, exposed to vacuum, extreme temperatures, ionizing radiation and micrometeorite bombardment.
Given Whitaker’s success with locating Surveyor 1, he was asked to locate precisely Surveyor 3. It was a tougher task than finding Surveyor 1. Because Surveyor 3 had landed in a crater, the view was restricted, but Whitaker again poured over the best images he could find, and believed he had found the landing site.
Apollo 12 launched on November 14, 1969, and, other than being struck by lightning twice within the first minute after it lifted off, had an uneventful trip to the Moon. On November 19, the landing module, Intrepid, headed into a crater and safely touched down. When Mission Commander Pete Conrad stepped out onto the lunar surface, he saw Surveyor 3, about 200 meters away. Ewen Whitaker had gotten it right.
November 12, 2019
https://theconversation.com/apollo-...the-first-pinpoint-landing-on-the-moon-126100
Excerpts:
When Apollo 11 landed on the Moon, it was a giant leap for mankind and a huge success for American engineering, but there was one aspect of the mission that hadn’t really gone as planned. When Neil Armstrong manually guided the lunar module to a safe touchdown, he had to override the computer which had the craft landing in a field of boulders. It left the demonstration of precision automated guidance to Apollo 12.
Fifty years ago this month, Apollo 12 successfully landed within a few hundred meters of its target, 400,000 kilometers (248,500 miles) away from where it lifted off. A key figure responsible for that precision landing was an unassuming Englishman living in the Arizona desert, Ewen Whitaker. Without the aid of computers or GPS, but with patience and an exhaustive knowledge of the geography of the Moon, Whitaker pinpointed where a robotic spacecraft had landed two years earlier.
When NASA’s Surveyor 1 became the first robotic spacecraft to perform a soft landing on the Moon, in 1966, Whitaker wasn’t officially part of the team. But when the team studied the images from Surveyor 1’s camera, and published the location where they thought they had landed, Whitaker disagreed. When he examined the images of the peaks and craters and compared them to the highest-resolution images of the Moon’s surface available, he concluded the spacecraft was actually a few kilometers away from the published location. The team agreed.
NASA had landed the Surveyor 3 unmanned craft in 1967, and the location had several advantages for an Apollo 12 landing site. It was clearly an area where a spacecraft could safely land; it was near the equator, which made it easily accessible. And, if the landing was close enough to Surveyor 3, the astronauts could walk over and remove pieces of it to bring back to Earth. That way, scientists could study the wear and tear on the materials after spending two years on the lunar surface, exposed to vacuum, extreme temperatures, ionizing radiation and micrometeorite bombardment.
Given Whitaker’s success with locating Surveyor 1, he was asked to locate precisely Surveyor 3. It was a tougher task than finding Surveyor 1. Because Surveyor 3 had landed in a crater, the view was restricted, but Whitaker again poured over the best images he could find, and believed he had found the landing site.
Apollo 12 launched on November 14, 1969, and, other than being struck by lightning twice within the first minute after it lifted off, had an uneventful trip to the Moon. On November 19, the landing module, Intrepid, headed into a crater and safely touched down. When Mission Commander Pete Conrad stepped out onto the lunar surface, he saw Surveyor 3, about 200 meters away. Ewen Whitaker had gotten it right.
