Intelligence officials and a top secret U.S. military strike team called upon a fleet of navigation, communications and imaging satellites in the raid on Osama bin Laden's compound in Pakistan.

A DigitalGlobe imaging satellite collected this view of the bin Laden compound Jan. 15, 2011. Credit: DigitalGlobe
 
With President Barack Obama and his national security team following events from the White House, a group of elite U.S. Navy special forces operators rode helicopters Sunday night to the sprawling compound occupied by Osama bin Laden, killing the wanted terrorist and taking custody of his body.

Situated in Abbottabad, a city just outside the Pakistani capital of Islamabad, the compound was surrounded by walls up to 18 feet high and topped with razor wire. Its existence and location were confirmed in August 2010 after years of questioning detainees and tracking couriers U.S. intelligence officials believed were linked to bin Laden.

In the months since August, officials collected more intelligence on the number of individuals living in the compound, including the probable location of bin Laden.

"The outer features of the compound were studied intensively and there were certain assessments made about where individuals were living and where bin Laden and his family were," said John Brennan, assistant to the president for homeland security and counterterrorism.

The National Reconnaissance Office, an agency within the U.S. government's intelligence community, operates fleets of classified optical and radar imaging satellites with unmatched resolution for day-and-night surveillance.

The observation spacecraft could have mapped the bin Laden compound, while NRO eavesdropping satellites could have listened for radio transmissions in the area.

"Intelligence cases aren't necessarily built overnight, and it did take time and several months vetting of our information to ensure that we had the highest possible confidence in the information at our disposal," a senior intelligence official said on background.

The intelligence official named the Central Intelligence Agency, the National Security Agency and the National Geospatial-Intelligence Agency, or NGA, as key participants in the information analysis.

The NGA uses imagery from spy planes, drones and satellites to create detailed maps of military targets and other critical sites.

The U.S. government also uses commercial satellite imagery supplied by DigitalGlobe and GeoEye spacecraft in low Earth orbit. DigitalGlobe released two images of the bin Laden compound this week, including a snapshot less than four months old.

Satellite data, coupled with aerial imagery and human intelligence, likely painted a picture of life in the compound for the military to act upon during the assault.

"They didn't know when they got there exactly what some of the internal features of it would be, but they had planned, based on certain observable features of the compound, how to carry it out," Brennan said.

When the time came for the top secret raid, helicopters flew into Pakistan beneath radar coverage with the help of Global Positioning System satellites orbiting 12,500 miles above Earth.

With more than 30 satellites, the ultra-precise navigation system, operated by the U.S. Air Force, not only guides civilian travelers on the road. It also provides pinpoint targeting data for missiles, airplanes, helicopters and ground forces.

Key leaders joined President Obama in the White House Situation Room to track the raid in real-time.

"We were able to monitor in a real-time basis the progress of the operation from its commencement to its time on target to the extraction of the remains and to then the egress off of the target," Brennan said.

Brennan offered no details on how administration officials monitored the events halfway around the world.

"I'm not going to go into details about what type of visuals we had or what type of feeds that were there, but it gave us the ability to actually track it on an ongoing basis," Brennan said.

Artist's concept of a Milstar satellite in orbit. Credit: Lockheed Martin
 
The Air Force's network of secure, jam-resistant Milstar satellites are designed to give the president, secretary of defense and the U.S. military with assured communications. The satellites route communications onboard without the need for land-based relay stations, making messages less likely to be intercepted, according to an Air Force fact sheet.

Covering every segment of the globe except for polar regions, the satellites can transmit up to 1.54 megabits per second of data over 32 channels.

The five Milstar satellites receive transmissions from small user terminals such as cameras and radios carried by the Navy assault team that descended on bin Laden's compound. Live video can be beamed from satellite to satellite before reaching the White House or the Pentagon, giving the president and other officials a nail-biting front row seat to the operation.

"It was probably one of the most anxiety-filled periods of time, I think, in the lives of the people who were assembled here yesterday," Brennan said Monday. "The minutes passed like days."

The Navy operates its own UHF communications satellites for mobile users, but their bandwidth capability falls short of the capacity of the Air Force Milstar network.

Intelligence officials could have also called upon NRO's own communications satellites, Air Force weather observatories, civilian spacecraft and international platforms in the days and hours before the attack.