"Running a day late, a United Launch Alliance heavy-lift Delta 4 rocket thundered
away from Cape Canaveral early Sunday, boosting NASA’s $1.5 billion Parker Solar
Probe into space on a daring seven-year mission to “touch the sun” with repeated
trips through the star’s blazing outer atmosphere.

Passing within 3.8 million miles of the sun’s visible surface — well within the
shimmering halo of the outer atmosphere, or corona — the spacecraft’s heat shield
will endure 2,500-degree heating while whipping past the star at a record 430,000
mph, fast enough to fly from New York to Tokyo in less than a minute.

The goal is to help scientists figure out what makes the corona hotter than the
sun’s visible surface and what accelerates charged particles to enormous
velocities, producing the solar wind that streams away from the corona in all
directions."

See:

https://spaceflightnow.com/2018/08/1...toric-mission/