The Comet Rendezvous Asteroid Flyby (CRAF) was a cancelled plan for a NASA-led exploratory mission designed by the Jet Propulsion Laboratory during the mid-to-late 1980s and early 1990s, that planned to send a spacecraft to encounter an asteroid, and then to rendezvous with a comet and fly alongside it for nearly three years.

Most of CRAF's scientific objectives were later accomplished by the smaller NASA spacecraft Stardust and Deep Impact, and by ESA's flagship Rosetta mission.

Designed to be the first of the planned Mariner Mark II series of spacecraft, CRAF was to closely examine a comet during a part of its orbit around the Sun.

The trajectory would carry CRAF out to the asteroid belt, where a propulsion maneuver would send the spacecraft back toward Earth for a gravity assist boost.

The comet rendezvous would allow study of matter that scientists think is the original, relatively unchanged material left behind when a cloud of dust and gas collapsed to form the Solar System 4.6 billion years ago.

On March 31, 2003, the Comet Rendezvous Asteroid Flyby, first primary mission of Mariner Mark II, would end.

CRAF and SOTP were to use identical Mariner Mark II spacecraft, but each was to carry unique science instruments.

And because of the long duration of the planned rendezvous — almost three years — it was expected to fill in many of the major gaps in scientific understanding of the strange objects.