Until the beginning of the Space Age in 1957, our only knowledge of the other members of our solar system came from viewing and studying objects from Earth – with naked eyes for most of human history, and then with Earth-bound telescopes for 350 years. What we learned from these observations – especially telescopic – was considerable,yet there were still great mysteries surrounding our neighbors. Many still wondered if there might be life on Venus, or at least conditions hospitable to life. Was the Moon as dry as it appears, and was it covered with a deep layer of dust that would engulf anyone landing on its surface? And did Mars have city-linking canals or any other evidence of Martian life, living or extinct?
In this and future columns we’ll look at some of what we’ve learned about our solar system neighbors in the last half century. And since our first Space Age explorations were of our nearest neighbor, the Moon, that’s where we’ll start with this column.
In January 1959, the USSR’s Luna 1 became the first human-made craft to escape Earth’s gravity; designed to crash-land on the Moon, it missed but became the first spacecraft to fly by the Moon and go into orbit around the Sun. In September 1959, Luna 2 did successfully crash-land on the Moon, becoming the first human-made object to come into contact with another solar system body.
The Moon is locked in synchronous rotation in its orbit around Earth so the same side always faces us. The result is that no human had ever seen the Moon’s other side until 1959 when Luna 3 circumnavigated the Moon and gave us our first photos of the Moon’s farside. As might have been expected, it was found to be far more crater-covered than the nearside, being more exposed to incoming meteoroids and other space debris.
In 1964 NASA’s Ranger 7 returned the first high-resolution TV images of the Moon before its planned crash onto the Moon’s surface. Then in 1966 USSR’s Luna 9 soft-landed and returned the first panoramic TV images of the Moon’s surface, dispelling concerns about a deeply dust-covered lunar surface. Later in 1966 NASA’ Surveyor 1 also soft-landed and generated many more images of the Moon’s surface as well as data about lunar soil.
Momentous history was made in July 1969 when Apollo 11 astronauts Neil Armstrong and Buzz Aldrin landed and walked on the Moon. In addition to providing truly close-up images and accounts of the Moon’s surface, they returned with over 50 pounds of lunar soil and rocks for scientific study.
In 1970 USSR’s Luna 17 landed the first successful robotic rover (Lunakhod 1) on the Moon which during its several months of operation returned thousands of images and more data about lunar soil. Unfortunately this important feat was overshadowed by NASA’s manned Apollo missions.
After the final Apollo mission in December 1972, lunar exploration lost some of its glamour until 1994 when NASA’s Clementine orbiter returned data suggesting the existence of large quantities of frozen water in the Moon’s permanently shadowed polar regions. NASA’s Lunar Prospector orbiter returned more data supporting the possibility of lunar water ice in 1998.
The past decade has seen several more successful lunar orbital and impactor spacecraft from a growing number of countries. While these missions continue to add to our knowledge about the Moon, including more evidence of lunar water, none has yet produced any dramatic new discoveries – but some missions are ongoing and others are in the works, so stay tuned.
Stargazer appears twice monthly. Paul Derrick is an amateur astronomer who lives in Waco, TX. Contact him at 918 N. 30th, Waco 76707, (254) 753-6920 or email@example.com. See the Stargazer Web site at stargazerpaul.com.