- Parker Solar Probe
- 343,180 kilometre(s) per hour
- Not Applicable ()
At 3:27:52 a.m. UTC on 6 November 2018 (10:27:52 p.m. on 5 November 2018 EST), the Parker Solar Probe reached the perihelion of its first orbit having accelerated to a speed of 95.3278 km/s (343,180 km/h; 213,242 mph) relative to the sun.
The term "perhelion" describes the point in an orbit when an object is closest to the body it is orbiting (the opposite, distant point is called the "aphelion"). Until perihelion, the orbiting object is being pulled "deeper" into its parent body's gravity well, accelerating as it closes in. After perihelion, it is "rising" out of the gravity well, losing speed as it moves away.
This record will stand until Parker's next perihelion, in April 2019, and won't change substantially until after December 2019, when Parker is due to use a second gravity assist from Venus to further tighten its orbit. The probe is set to use a series of Venus flybys over the next 6 years to gradually get ever faster and closer to the sun.