We constantly fret about external threats and foreign attacks — but its an entirely other level of concern when the offensive comes from outer space. Two close calls with asteroids earlier this year were a wake-up call about the threat space rocks pose to our planet. A 150-foot asteroid sideswiped the Earth at one-fourteeth the distance between our planet and the Moon. And that threat became real when a large meteor exploded over Russia on February 15th, injuring over 1,100 people from the damage by the shockwave.

On Friday afternoon, an asteroid larger than both of those combined will make its closest approach to Earth at 4:59 EST on May 31st. The asteroid, named 1998 QE2, is 1.7 miles (2.7 km) in diameter. The moniker follows a coding convention from the US Minor Planet Center in Cambridge, Massachusetts. But the name just happens to describe its enormous girth at just over 9 times the size of the Cunard luxury liner Queen Elizabeth 2. In fact, it’s so large it’s been found to be carrying its own moon in tow. If an asteroid of this size hit Earth, the consequences could be devastating on a global scale. Fear not, though: this asteroid will speed by us at comfortable distance of 3.6 million miles.

However, the distance is close enough for two powerful radar facilities to catch detailed images. Both the Goldstone radar telescope in California and the Aricebo telescope in Puerto Rico will bounce microwave signals off 1998 QE2. The returning radar echoes contain surface details and other rich data that will help NASA scientists learn more about 1998 QE2 and add to the general knowledge of other known near-earth objects.