Carlos Carrion did so while at work at the renowned JPL campus in Pasadena, California.
The 62-year-old defendant told a federal judge in Los Angeles that he accepted full responsibility for "the shame and pain I helped to create" and that "words are not adequate" to describe his remorse.
"I blame no one," he said.
Carrion added that he had been successfully undergoing treatment for sex addiction for four years.
"I am no longer the person I was," the gray-haired, bespectacled defendant told the judge, as his wife, daughters and pastor looked on.
Despite sentencing guidelines that call for up to four years in federal prison, US District Court Judge Stephen V. Wilson spared Carrion time behind bars, sentencing him instead to probation.
Wilson noted Carrion had already been fired from his job as a result of his conduct, has a felony conviction on his record, and was dealing with "extraordinary" circumstances at home, including caring for two loved ones with psychiatric issues.
"He has suffered severe consequences," Wilson said. "Not every crime needs a prison sentence."
Assistant US Attorney Cassie D. Palmer requested 18 months imprisonment and a lifetime of supervised release in a memorandum submitted prior to sentencing. Palmer wrote that Carrion claimed to have stopped viewing child pornography "cold turkey" following his termination from JPL in 2013 but that evidence "strongly suggests otherwise." She said Carrion's home IP address connected to a site known to share child pornography on multiple occasions in 2014.
The judge did not offer Palmer an opportunity to speak about her position prior to imposing sentence.
Carrion's sentence includes a year of house arrest and 10 years of supervised release. It marks a humiliating low point in an otherwise high-flying career.
Carrion "operated and designed" the ground system that gave the commands to take and reconstruct images of "Saturn and its rings, Jupiter and its moons" and various other galactic images, according to his LinkedIn biography.
"If it's flying in deep space," Carrion wrote on his LinkedIn profile, "it likely has my imprint on it."
Investigators from NASA's inspector general's office became aware of inappropriate internet browsing on the JPL network in spring 2012, according to court papers. Someone had been accessing websites known to host sexually explicit content, including stories about child abuse. An investigation revealed that the traffic was coming from Carrion's government-issued computer.
Agents seized Carrion's computer and other government-issued items, including two external hard drives and 22 CDs and digital video discs.
On them, investigators found more than 5,000 images and 65 videos of child pornography and 60 child sex abuse stories.
Nearly 3,000 of the images and five of the videos involved children under age 12, according to prosecutors.
Three of the victims were identified by the National Center For Missing and Exploited Children. One, identified in court papers as "Misty" provided a victim impact statement to be considered by the judge prior to sentencing.
Misty said she was sexually abused by her uncle beginning at age 4. Images of the assaults were put on the internet and downloaded by Carrion, according to prosecutors.
Misty said she continues to feel victimized by knowing that she is "forever in pictures that people are using to do sick things."
"What happened to me hasn't gone away," she said. "It will never go away."