Two German satellites orbiting within 380 yards of each other are preparing to create the most detailed map ever made of Earth's entire surface, officials said.

The radar satellites TanDEM-X and TerraSAR-X will make 3-D maps of the surface as they orbit the globe, sweeping around the planet at more than 14,000 mph, the BBC reported.

TerraSAR-X was launched in 2007 and TanDEM-X was put in orbit in June, then slowly brought closer and closer to its companion.

The final maneuvers to bring them together were made step-by-step over the past week, German space agency officials said.

"It's tricky and I must confess we've all been a bit nervous," Manfred Zink said.

The two satellites will soon begin observations to measure the variation in height across the globe to an accuracy of around 6 feet, the BBC said.