what is the furthest, in terms of distance, a space probe has travelled?

Voyager 1
9.3 Billion Miles

Pioneer a space probe send to study planets is now going away from Solar system and is about 70Astronomical units from Earth.Voyagers followed. So Pioneer space craft that is twice the distance of pluto should be the furthest probe
Chandramohan

yes, Voyager 1, launched in 1977 Is now 104 AU from Earth.

That is 104 times Earth – sun distance (ie multiply by 93 million for miles)

Just to get that in perspective, the nearest star is about 250,000 AU.

So, in 33 years Voyager 1 has gone just 1/2500th the way to the nearest star (not that it is going in that direction)

Voyager 1 is currently the most distant space probe from our sun.

November 22, 2007
DISTANCE FROM SUN -- 9,755,850,831 miles
CURRENT VELOCITY -- 38,280.69077 mph

Voyager 1 is the farthest human-made object from Earth, moving away from the Earth and the Sun faster than any other probe. As of August 10, 2007, Voyager 1 is over 15.49×10^9 km (103.6 AU, or 9.6 billion miles) from the Sun.

The other 3 exo-system probes are:
- Voyager 2 (as of August 10, 2007, it was about 83.5 AU from the sun)
- Pioneer 10 (the last, very weak signal from Pioneer 10 was received on January 23, 2003, when it was 7.5 billion miles or 12 billion kilometres from Earth)
- Pioneer 11 - on September 30, 1995 routine daily mission operations stopped - it was 6.5 billion km from Earth. The last communication with the probe was in November 2005.

Both pioneer missions and Voyager missions have deaprted the solar system. All in different dirrections.

Here is some basic info. Check out the links for more.

Launch dates;
Pioneer 10, March 2, 1972
Pioneer 11, April 5, 1973
Voyager 1, September 5, 1977
Voyager 2, August 20, 1977

Pioneer 10 link:
http://www.nasa.gov/centers/ames/news/releases/2003/03_25HQ.html

Pioneer 10 & 11 link:
http://nssdc.gsfc.nasa.gov/planetary/pioneer10-11.html

Voyager 2 link:
http://voyager.jpl.nasa.gov/
http://nssdc.gsfc.nasa.gov/planetary/voyager.html