It seems not even the high-tech NASA is safe from digital intruders: The space agency's computer systems were breached by hackers 13 times last year, according to Congressional testimony this week.

"These incidents spanned a wide continuum from individuals testing their skill to break into NASA systems, to well-organized criminal enterprises hacking for profit, to intrusions that may have been sponsored by foreign intelligence services seeking to further their countries’ objectives," said Paul Martin, NASA's inspector general, in his Congressional testimony released on Wednesday.

"Some of these intrusions have affected thousands of NASA computers, caused significant disruption to mission operations, and resulted in the theft of export-controlled and otherwise sensitive data, with an estimated cost to NASA of more than $7 million," he continued.

Martin gave Congress detailed information about some of the attacks.

In one instance, the agency discovered late last year an intrusion into its system by hackers working through a China-based IP address. Martin said that the hackers gained full access to the network of NASA's Jet Propulsion Laboratory, allowing them to view, copy, delete and otherwise tamper with classified information.

Before closing the door behind them, the hackers uploaded software allowing them access to other NASA systems and managed to adeptly hide their digital tracks.

In a separate event, hackers managed to grab computer access codes from more than 150 NASA employees. According to Martin, the agency failed to move quickly enough to ensure that those hackers wouldn't be able to use the codes to gain access to its networks.

According to Martin, the "sophistication" of cyberattacks against NASA has been steadily increasing. He added that NASA spends more than $1.5 billion annually on "IT-related activities," which includes approximately $58 million for "IT security."

Martin also pointed out what NASA stands to lose when its computer systems are compromised by hackers.

"Some NASA systems house sensitive information which, if lost or stolen, could result in significant financial loss, adversely affect national security, or significantly impair our nation’s competitive technological advantage," said Martin. "Even more troubling, skilled and committed cyber attackers could choose to cause significant disruption to NASA operations, as IT networks are central to all aspects of NASA’s operations."

The news of the NASA hacks comes at a turbulent time for cybersecurity in the U.S.

On Friday, the director of the Federal Bureau of Investigation said that hackers could top terrorists as the main threat to the U.S. in the near future. Meanwhile, Congress is debating two competing cybersecurity bills intended to bolster the government's defenses against digital attacks.

Does the news of the successful hacks against the high-tech NASA come as a surprise to you? Let us know in the comments below.

Images courtesy of iStockphoto, LaserLens