[meteorite-list] Apollo 13's Booster Impact

[Meteorites USA]

Saw this, though it was cool. But of course I have questions. ;)
http://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/lroc-20100322-apollo13booster.html

How fast was it going upon impact? Why is the crater only 30 meters in 
diameter, while the booster was almost that long? Was the booster not 
traveling fast enough to make a larger crater? What other factors were 
in play to create the crater, material the booster was made of, size, 
weight, speed, angle of descent, all of the above?

Regards,
Eric Wichman