MKI scientists are studying the solar wind from its origin at the Sun to the boundaries of the solar system. They have instruments operating on two current spacecraft, the Wind spacecraft which observes the solar wind just upstream of Earth and the Voyager 2 spacecraft which is over 100 AU from the Sun and near the outer boundary of the heliosphere. They also participate in development of two future missions. DISCOVR will make fast solar wind measurements upstream of Earth and Solar Probe Plus will make the first observations close to the Sun.