Parker Solar Probe will go 25 times closer to the sun and withstand 520 times the solar intensity

The Parker Solar Probe should be launched August 11, 2018 on a Delta IV Heavy class launch vehicle and an upper stage based on the STAR-48B solid rocket motor. Interplanetary gravity assists will provide further deceleration relative to its heliocentric orbit, which may result in a heliocentric speed record at perihelion. The probe will achieve a velocity of up to 200 km/s (120 mi/s), which will temporarily make it the fastest manmade object, almost three times as fast as the current record holder, Helios-B. At closest approach, Parker Solar Probe will move around the Sun at approximately 430,000 mph (700,000 kph). That’s fast enough to get from Philadelphia to Washington, D.C., in one second.

The probe will start making its first close passes of the sun in 2024. It will have to swing around Venus several times to get the speed and orbits to get closer to the sun.

The Parker Solar Probe will be the first spacecraft to fly into the low solar corona. It will determine the structure and dynamics of the Sun’s coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate energetic particles. The Parker Solar Probe mission design uses repeated gravity assists at Venus to incrementally decrease its orbital perihelion to achieve multiple passes of the Sun at approximately 8.5 solar radii, or about 6 million km (3.7 million mi; 0.040 AU).

Mercury’s distance from the Sun ranges from 46,000,000 to 70,000,000 km (29,000,000 to 43,000,000 miles). The Parker solar probe will get about 8 times closer than Mercury to the sun.

The spacecraft’s systems can survive incident solar intensity 520 times the intensity at Earth orbit by using a solar shadow-shield. The solar shield is 11.4 cm (4.5 in) thick and is made of reinforced carbon–carbon composite, which is designed to withstand temperatures outside the spacecraft of about 1,377 °C (2,511 °F).

The goals of the mission are:

* Trace the flow of energy that heats the corona and accelerates the solar wind.
* Determine the structure and dynamics of the magnetic fields at the sources of solar wind.
* Determine what mechanisms accelerate and transport energetic particles

European Solar Orbiter in 2019 will launch and orbit at 60 solar radii

The EuropeanSolar Orbiter will make observations of the Sun from an eccentric orbit moving as close as ~60 solar radii (RS), or 0.284 astronomical units (AU), placing it inside Mercury’s perihelion of 0.3075 AU.