space probes definition
Artist's concept of Mariner 9, the first probe to orbit Mars. Image credit: NASA We received this question from fourth-grade students in Fresno, California. JPL's Homework Help page provides basic information and suggestions for further research. A probe is a spacecraft that travels through space to collect science information. Probes do not have astronauts. Probes send data back to Earth for scientists to study. The First Probes Sputnik 1 was the first probe to go into space. It was launched on Oct. 4, 1957, by the former Soviet Union. On Jan. 31, 1958, the United States sent a probe called Explorer 1 into space. These first probes studied Earth from space. They also learned what it's like to be in space. This was the beginning of the Space Race between the United States and Soviet Union.