Mariner 10 flew by Mercury for the first time in 1974. Launched November 3, 1973, it first flew by Venus on February 5, 1974. After it flew by Mercury, it orbited the sun and came close to Mercury again on September 21, 1974. A third encounter happened on March 16, 1975. Data from Mariner 10 included 2,800 photographs of Mercury as well as information on a helium atmosphere and an iron-rich core. Mariner 10 ran out of fuel and stopped transmitting data on March 24, 1975. Scientists believe that it continues to orbit the sun. Children could learn more at: Mariner 10.
Genesis was launched in 2001. The space vehicle traveled to the sun and gathered particles of the sun on its way. A capsule then turned around and returned to earth. It crash landed (the drogue parachute failed to deploy) in Utah on September 8, 2004. Some of the samples were contaminated by earth soil on impact, but many collectors were intact. Scientists used the data to learn more about the sun’s composition and history. Children could learn more by clicking Genesis Spacecraft.
Orbiting Geophysical Observatory 1 was launched 1964. Five other Orbiting Geophysical Observatories were launched between 1965 and 1969. These satellites measured the earth’s magnetosphere and provided data about the earth and sun. The last of the six stopped operating in March 1972. Older children can learn more at: OGO.