It’s tempting to assume faster engines make faster spacecraft, but Parker Solar Probe’s record 430,000 miles per hour came mostly from gravity: seven Venus flybys spent nearly seven years bending its orbit closer to the Sun, until the Sun’s own pull accelerated it faster than any human-made object in history.

It is easy to imagine the fastest spacecraft as the one with the most ferocious engine. Parker Solar Probe is a useful correction to that instinct. Its record speed of about 430,000 miles per hour was not mainly a feat of continuous thrust. It was a feat of trajectory design, Venus flybys and gravity. NASA’s [...] The post It’s tempting to assume faster engines make faster spacecraft, but Parker Solar Probe’s record 430,000 miles per hour came mostly from gravity: seven Venus flybys spent nearly