Explorer 10 installation before launch.
While The U.S. and the U.S.S.R. raced against each other to put a man in space, science marched on. On April 19, 1961, the Explorer space probe sent back information that helped scientists understand better the interaction of the solar wind with magnetic fields. Ever since the discovery of Earth's Van Allen Radiation belt using our first probe, Explorer 1, NASA scientists had been gaining more and more information about what the space environment was like beyond Earth's orbit.
Thor-Delta on pad 17. (Actually Explorer 14 assembly)
With the placement of Explorer 10 in Earth's orbit on March 25, 1961, we learned that the strong solar wind actually was helping to extend the Sun's magnetic field out beyond Earth's orbit. The probe gathered a lot of information about our own magnetic field and the interaction of the solar wind and the Earth.
Experiment simulating solar wind / magnetic field interaction.
We've eventually learned that the solar wind and particles from the Sun can play havoc with our orbiting satellites. In fact, strong solar winds can even cause some spacecraft to eventually lower their altitude. This was the case with the abandoned Skylab space station, which eventually was lowered so much that it got caught by the atmosphere and burned up earlier than predicted.
Explorer 10 itself burned up on re-entry on June 1, 1968.