The first space probe, Sputnik 1, was invented in 1957 by a large team of engineers, scientists and designers employed by the Soviet Union and headed by rocket pioneer Sergei Korolev. A space probe is any unmanned, automated instrument sent into space to observe phenomena and collect scientific data.
The first American space probe, the satellite Explorer 1, was launched in February 1958 and discovered the Van Allen radiation belts. The second was Vanguard 1, which was launched in March 1958 and is still in orbit around Earth.
A deep space probe is differentiated from an orbital probe such as a Sputnik 1 and Explorer 1 in that it leaves the orbit of Earth. The first deep space probe was Luna 1, launched by the Soviet Union in 1959. It successfully completed a close fly-by of the moon.