Re: What is the speed of a comet compared to a space rocket?

A probe that is sent to Earth orbit cannot exceed the speed of 
25,000 miles per hour. Probes that are sent to explore other 
bodies of the Solar System must exceed this speed initially 
although their speed decreases later on the trip. Typically 
a probe that is sent to an orbit near the Earth's orbit 
will have a speed around 70,000 miles per hour. 

Comets have very different speeds, and their speed increases 
as they approach the Sun. Those with orbits near 
the Earth have also speeds around 70,000 miles per hour. 
Comets with very elongated orbits can have speeds up to 500,000 
miles per hour at the closest point of their orbit to the Sun. These 
comets can take millions of years to return to the Sun vicinity. At 
their farthest point in orbit their speeds is minimum and can be 
only a few thousand miles per hour. 

Vladimir Escalante Ramirez