There are slides devoted to this topic: Lecture 6b, pp. 55-62.
The Wikipedia page on the SSEC (which you should be careful not to confuse with the University of Manchester’s SSEM) provides a good introduction for the computer.
Read “IBM SSEC” on Columbia’s Computing History site for more information on the topic.
To learn more about the SSEC and space travel, check out the article “The SSEC: IBM’s Electronic Brain and Reaching the Moon.”
IEEE: “The SSEC in Historical Perspective,” Charles J. Bashe: This article covers the history, functions and significance of IBM’s Selective Sequence Electronic Calculator (SSEC), which became operable in 1948 and was the first electronic stored program computer. Much of the article also discusses the computers preceding the SSEC, namely the the Harvard Mark I and the 603 Electronic Multiplier.