99% of space junk goes unnoticed, but not for long

Companies and the military keep an eye on around 170 million bits of space junk circling the Earth. However, their ability to spot these objects is restricted to those larger than a softball. Radar or optical systems can only track such sizable chunks, which make up less than 1% of the overall space junk population. They’re working on a fresh method to identify space debris that’s tinier than one millimeter in diameter.

They’ve got this project called Space Debris Identification and Tracking (SINTRA). They’re trying out a cool new method that involves high-tech sensors picking up plasma waves generated by fields of debris. These new sensors team up with the ones we already have, like ground-based radar, tracking satellites, and optical sensors. The goal is to spot and track space debris as small as one millimeter.

“Right now, we detect space debris by looking for objects that reflect light or radar signals,” said Nilton Renno, from the University of Michigan and a professor of climate and space sciences, and engineering and aerospace engineering. “The smaller the objects get, the harder it becomes to get sunlight or radar signals strong enough to detect them from the ground.”

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SINTRA to detect electrical signals from space debris

So, SINTRA is this four-year gig aimed at boosting the sensors that can spot signs of orbital debris. It’s a team effort funded by the Intelligence Advanced Research Projects Activity’s Space Debris Identification and Tracking Program.

In on the action are military contractor Blue Halo and a bunch of universities, like the University of Michigan and the University of Alaska Fairbanks. Plus, you’ve got heavy hitters like MIT Lincoln Laboratory, Naval Research Laboratory, Los Alamos National Laboratory, and JHU Applied Physics Laboratory in the mix.

So, the deal with SINTRA is to hunt down the electrical signals given off by clusters of space debris. When chunks of space junk smash into each other, they break into itty-bitty pieces, and some of those bits turn into charged gas because of the heat from the collision.

“When the cloud of charged gas and debris fragments expands, it creates lightning-like energy bursts, similar to signals produced by static sparks that appear after rubbing a freshly laundered blanket,” said Mojtaba Akhavan-Tafti, a lead scientist on the project for the University of Michigan.

Here’s how the whole system will work

When charged gas and debris bits get close, they trigger electric field pulses, causing extra electrical bursts. These signals stick around for just a tiny moment, but they might be the key to keeping tabs on space debris bits and the tiny fragments that pop up when debris smashes together.

Here’s a scenario: when two bits of aluminum crash at the usual speeds in orbit, they let out a powerful electrical burst. The University of Michigan crew ran some recent computer simulations, and they say a 26-meter dish with a top-notch radio receiver on the ground can pick up on this. These electric field pulses should be spot-on detectable with more advanced radio arrays, like NASA’s Deep Space Network.

If SINTRA pulls it off, we’re talking about the first-ever ability to track those super tiny bits of debris, making things way safer for space operations worldwide. Just so you know, the space junk in low Earth orbit (LEO) is cruising at an average speed of 36,000 km/hr (22,500 MPH). So, even the tiniest pieces could mess up operational satellites big time.

Still, there’s a ton of work left to get the SINTRA concept up and running. The frequency of those electrical signals can shift based on how fast the collision happens, and the type of stuff the debris is made of messes with a bunch of factors too. That could make detection a bit tricky.

Leveraging NASA’s Deep Space Network

According to a University of Michigan press release, Akhavan-Tafti mentioned that for those electric signals to be visible, they’ve got to outshine the background signals from the ground instrument and make it through the Earth’s upper atmosphere.

In this project, the crew is kicking things off by checking out actual signals with NASA’s Deep Space Network. They’re also diving into data from hypervelocity experiments at the Naval Research Laboratory and NASA’s Ames Research Center. With the help of lasers at these facilities, the team can shoot various types of debris at targets with different orbital speeds and then study the electric emissions that pop up from the impact.

So, if these experiments spill the beans on how to pick up a bunch of different electrical signals from space debris smash-ups, it could mean figuring out not only where the debris is but also getting the scoop on what it actually looks like and what it’s made of.

In a press release a while back, the US Intelligence Advanced Research Projects Activity agency spilled the beans, saying the SINTRA program aims to patch up the holes in existing space debris monitoring systems. Right now, those systems only keep tabs on debris chunks that are bigger than four inches.

They mentioned that spotting, tracking, and understanding dangerous space debris that’s currently off the radar would help ensure the safe functioning of valuable space assets all around the globe.

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ESA also working on taking out space debris

No doubt, things need a shake-up. Yet, in a world where not every country is gung-ho about teaming up and private companies are cluttering up space, making a change is a real challenge. The ESA is ramping up its efforts with a new strategy they’re calling the “Zero Debris Approach.”

The space junk problem isn’t some distant headache—it’s going down right now. Take 2009, for example. Two satellites collided over Siberia. One was already out of commission, but the other was still operational. Not only did it knock out an active Iridium satellite, but the collision also unleashed a load of additional debris. The kicker? This crash was totally predicted. Out of all the satellites that could’ve bumped into each other, these two weren’t even in the top 200 when it came to being at high risk for a close encounter.

Here’s another worry on the uptick—even if we stop launching more stuff, the danger of existing debris colliding could escalate the problem. The real nightmare is the Kessler syndrome, where these collisions spawn more debris, triggering a domino effect of crashes that might turn Earth’s orbit into a total no-go zone.

“It has been estimated that even in the case of no further launches into orbit, collisions among the existing space objects can lead to further growth in space debris population,” the ESA writes.