A former employee at the NASA Ames Research Center was sentenced today to five years in federal prison for possessing child pornography on his government computer.

Christopher Burt Wiltsee, 57, of Morgan Hill pleaded guilty in March, admitting that he had used his government computer to download child pornography from the Internet.

He admitted to possessing more than 600 images, including ones depicting sadistic and masochistic conduct, as well as pictures involving prepubescent minors.

At a hearing today in San Jose, U.S. District Judge Jeremy Fogel also ordered Wiltsee to pay a $25,000 fine.

Wiltsee is at least the third person connected with NASA Ames to be convicted of possessing child pornography.

In February, former NASA contract employee Ernst John Rohde, 63, of Stockton pleaded guilty to two counts of receiving child pornography. Fogel is to sentence Rohde on Sept. 24.

Former NASA employee Mark Charles Zelinsky, 56, of San Bruno pleaded guilty in December to possessing more than 600 images of child pornography on his government computer. U.S. District Judge James Ware sentenced Zelinsky in March to three years in prison.