Earth Space_exploration

space exploration has been used tool understand earth celestial object in own right. orbital missions can provide data earth can difficult or impossible obtain purely ground-based point of reference.

for example, existence of van allen radiation belts unknown until discovery united states first artificial satellite, explorer 1. these belts contain radiation trapped earth s magnetic fields, renders construction of habitable space stations above 1000 km impractical. following unexpected discovery, large number of earth observation satellites have been deployed explore earth space based perspective. these satellites have contributed understanding of variety of earth-based phenomena. instance, hole in ozone layer found artificial satellite exploring earth s atmosphere, , satellites have allowed discovery of archeological sites or geological formations difficult or impossible otherwise identify.

the moon


apollo 16 lem orion, lunar roving vehicle , astronaut john young



the moon

the moon first celestial body object of space exploration. holds distinctions of being first remote celestial object flown by, orbited, , landed upon spacecraft, , remote celestial object ever visited humans.

in 1959 soviets obtained first images of far side of moon, never visible humans. u.s. exploration of moon began ranger 4 impactor in 1962. starting in 1966 soviets deployed number of landers moon able obtain data directly moon s surface; 4 months later, surveyor 1 marked debut of successful series of u.s. landers. soviet unmanned missions culminated in lunokhod program in 1970s, included first unmanned rovers , brought lunar soil samples earth study. marked first (and date only) automated return of extraterrestrial soil samples earth. unmanned exploration of moon continues various nations periodically deploying lunar orbiters, , in 2008 indian moon impact probe.

manned exploration of moon began in 1968 apollo 8 mission orbited moon, first time extraterrestrial object orbited humans. in 1969, apollo 11 mission marked first time humans set foot upon world. manned exploration of moon did not continue long, however. apollo 17 mission in 1972 marked recent human visit there, , next, exploration mission 2, due orbit moon in 2021. robotic missions still pursued vigorously.

mars seen hubble space telescope