NASA's Solar Probe will actually touch the Sun

In untold ways, humanity is as clueless about our own star (the sun) as it was a generation ago.  But that should change soon after
the projected July 2018 launch of National Aeronautics and Space Administration (NASA) ’s Solar Probe Plus (SPP) — a $1.5 billion spacecraft that will travel closer to its surface than any previous man-made object.
Nearly 60 years after NASA first discussed sending a suicide probe into the Sun itself, the space agency is making good on a probe that will travel nearly ten times closer to our star than the planet Mercury.  The hope is that, in the process, Solar Probe Plus will provide new data about the Sun’s effects on everything from space weather to short term climate change.
     from: www.space.com
   Over a period of seven years and 24 close elliptical solar orbits, Solar Probe Plus and its 10 thermally-shielded science instruments will skirt our star’s roiling hot corona (or outer atmosphere).  Using seven Venus flybys to continually get closer to the Sun, the space craft will have to survive temperatures exceeding 2500 degrees Farenheit and impacts from hyper velocity dust particles.
   At its very closest approach of only 3.8 million miles from the Sun’s surface, Solar Probe Plus will be subjected to up to 475 times the solar irradiance experienced at Earth.  Thus, the science collection phases of the mission during close encounters are designed to be autonomous.  That is, without real-time direction from ground-controllers.
   Data taken during these collection phases will be saved on solid state recorders for subsequent downlink via a high gain antenna pointed back to Earth.
   The probe’s thermal protection system is an 8-foot-diameter, 4.5-inch-thick, carbon-carbon, carbon foam shield that sits atop the spacecraft. Basically, most of the entire spacecraft “hides” behind this shield during the spacecraft’s closest approach to the Sun, says McNutt.
   “The solar arrays do retract and there is a battery,” said McNutt.  “But even at [closest approach], part of the arrays remain illuminated to provide power.”
   McNutt notes that an active water circulation system from the back of the solar arrays to radiator panels which keep the arrays cool, a first for any spacecraft. He says the mission’s science goals focus on tracing the flow of energy that heats the solar corona and accelerates the solar wind.  Nagging questions include whether the sources of the solar wind steady or intermittent and the mechanisms that accelerate and transport the Sun’s energetic particles.
   In an effort to answer such questions, SPP will sample the solar wind during rising solar activity, while also directly imaging the Sun’s corona.
Meanwhile, we still are at a loss to explain or predict the Sun’s year- on-year anomalies during its 11 year solar cycles; the last two of which have seen a drastic reduction in sunspots.
It’s still unclear as to if there’s an actual link between the solar cycles and Earth’s climate.
“There certainly is suggestive circumstantial evidence,” said McNutt. “But how do very small variations in solar activity become a cause for multi-year variations in weather?"

from: www.forbes.com/tech