What fraction of light speed is that?

Everything we have ever launched is a rounding error next to light. Here is exactly how small a rounding error.

The speed Unit

52% of Parker Solar Probe

100,000 m/s is faster than 4 of the 7 references on this page.

Reference figures are measurements and are rounded; the unit conversion behind them is exact.

Every reference on this page, with its size and its ratio to your number
Reference	Size	Yours ÷ theirs	Note
airliner at cruise	250 m/s	400×
International Space Station	7,660 m/s	13.1×
Voyager 1	17,000 m/s	5.88×
Earth around the Sun	29,780 m/s	3.36×
Parker Solar Probe	191,000 m/s	0.524×	The fastest human-made object
solar wind	450,000 m/s	0.222×
speed of light	299,792,458 m/s	1/2,998

The Parker Solar Probe reaches 0.064% of light speed. At that rate the nearest star is still 6 800 years away.
The speed of light is exactly 299 792 458 m/s — not measured but defined, because the metre is defined from it.

Frequently asked

Because since 1983 the metre has been defined as the distance light travels in 1/299 792 458 of a second. Measuring c now means measuring the metre.

At 10% of light speed, Proxima Centauri takes 43 years. Nothing we have built comes within a factor of 150 of that.