Have there been other collisions in space?

According to Don Kessler, a former NASA expert on orbital debris and now an orbital debris and meteoroid consultant in Asheville, North Carolina, there have been three othyer hypervelocity incidents in orbit. However, the Iridium 33-Cosmos 2251 incident is the first to involve two satellite bodies.

December 23, 1991: Russian Cosmos 1934 collided with a piece of debris from Cosmos 926. Only two debris cataloged from Cosmos 1934. Altitude 980 kilometers.

July 24, 1996: French Cerise spacecraft collided with a piece of Ariane rocket body debris (from an explosion 10 years earlier). Part of a large boom on Cerise was severed. Only one piece of debris cataloged from Cerise (upper part of boom). Cerise later resumed operations. Altitude 685 kilometers.

January 17, 2005: U.S. Thor-Burner 2A rocket body (launched in 1974) collided with a piece of a Chinese rocket body which had exploded in March 2000. Only four debris cataloged from Thor-Burner 2A. Altitude 885 kilometers.

February 10, 2009: U.S. Iridium 33 spacecraft collided with Russian Cosmos 2251. Hundreds of debris detected. Altitude 790 kilometers.

David Wright of the Union of Concerned Scientists adds a few more incidents of interest to the list:

1997 - Inactive NOAA 7 satellite hit by uncataloged debris large enough to change its orbit and create additional debris.

2002 - Inactive Cosmos 539 satellite hit by uncataloged debris large enough to change its orbit and create additional debris.

2007 - Active Meteosat 8 satellite hit by uncataloged debris large enough to change its orbit.

2007 - Inactive NASA UARS satellite believed hit by uncataloged debris large enough to create additional debris.