Good fences make good neighbors, which is why the United States is building a space fence.
But the first thing to understand about the space fence is that it’s not actually a fence — it’s radar. And when it’s operational, pulsing up from an atoll in the Pacific, it will be able to track objects in space that are softball-sized, the Air Force says.
The purpose? To keep track of space debris, but also for deterrence, in order to keep U.S. assets in space safe from other powers that might want to attack them.
‘Bubble of Uncertainty’
There are 23,000 human-made objects orbiting the Earth, and about 1,300 of those are active satellites, according to Capt. Nicholas Mercurio, a public affairs officer for the Air Force.
Existing systems track those objects, and are able to detect pieces of debris that are about four inches long in low-Earth orbit, he said.
“The new space fence will have much greater sensitivity, allowing it to detect and track and measure an object the size of a softball, orbiting more than 1,200 miles in space,” Mercurio told FoxNews.com. The new system— which will detect objects in space as they pass through what Mercurio described as a “curtain of radar”— will be able to track objects that are about two inches long.
When tracking objects, the Air Force uses the term “bubble of uncertainty” to describe a satellite’s projected location when it nears another object, and if a satellite’s bubble overlaps with the bubble of a piece of debris, then that’s what the Air Force calls a “conjunction.” The new space fence, since it promises to be more accurate, will shrink those uncertainty bubbles, Mercurio said.
Brian Weeden, the technical advisor for the Secure World Foundation, has written a lengthy analysis of the space fence.
“We know through some scientific work, that there’s roughly half a million pieces of space debris larger than let’s say half an inch, but smaller than four inches, that’s there but we can’t track it right now,” Weeden told FoxNews.com “So one of the big reasons why the military is investing in the new space fence is to track those objects.”
This isn’t the first space fence. The original one was a radar system based in the continental United States, which the Air Force shut down in 2013.
“The decision itself was interesting in that it was wrapped up in the whole sequestration discussion. That was the rationale that the Air Force Space Command gave,” Weeden said. But that was just "part of the story," he said. “I think there’s a case to be made that shutting down the original was kind of part of the budget justification for the new one.”
“I think tracking more of the space debris, and particularly the smaller space debris objects, is a very good goal,” Weeden added. “I think there are a lot of questions, though, about whether this really is the most bang for the buck.”