NASA's Deep Space 1 New Millennium programme spacecraft will fly to within 2,000km (1,240 miles) of the comet Borrely at a relative speed of 60,000km/h (37,500mph) on 22 September, taking 32 black and white images of the planetary body's nucleus.
This will be the first exploration of a comet at such close quarters since the European Space Agency's Giotto, which made a fly-by of the comet Halley in March 1986.
The Borrely fly-by is a bonus for the $152 million mission, launched in October 1998 to demonstrate new technologies, such as an ion propulsion system, to fly on future NASA missions.
This part of the mission was deemed a success, despite the loss of a navigation camera which required an ingenious remote reprogramming of the spacecraft's software.
Source: Flight International