It's no secret that hackers haven't taken too kindly to the revelations about NSA snooping on telephone and Internet data. And according to reports, last week, a group of Brazilian hackers posted messages on U.S. government Web sites asking them to "stop spying us." But the sites didn't belong to the NSA — they belonged to NASA.

On the bright side, NASA spokesman Allard Beutel says, "At no point were any of the agency's primary Web sites, missions or classified systems compromised."

To clear up the confusion, we've created this short illustrated guide to help hackers tell the two agencies apart in the future.

What are they?

NASA is the National Aeronautics and Space Administration.

The NSA is the National Security Agency.

What do they, you know, do?

NASA describes its vision as "to reach for new heights and reveal the unknown so that what we do and learn will benefit all humankind." Long version: They're responsible for aeronautics research, supporting human and robot exploration missions into space, doing research about our solar system and the universe beyond, and developing space technology. Short version: They send things to space!

The NSA says it "leads the U.S. Government in cryptology that encompasses both Signals Intelligence (SIGINT) and Information Assurance (IA) products and services, and enables Computer Network Operations (CNO) in order to gain a decisive advantage for the Nation and our allies under all circumstances." That sounds like the long version. The short version is they are charged with doing foreign surveillance and data collection for national security purposes. And as we know from the Snowden leaks, they end up having their hands on a fair amount of domestic data as well.

Who leads them?

NASA's Chief Administrator is Charles Bolden, a retired United States Marine Corps major general and former astronaut, who has led the agency since 2009.

The NSA's director is Gen. Keith B. Alexander. He's a four-star general and also serves as chief of the Central Security Service and commander of the United States Cyber Command. He's been in charge of the NSA since 2005 after a stint as deputy chief of staff for the U.S. Army from 2003 to 2005.