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"Undetectable" space junk is now easier to detect

The pressing issue of tracking minuscule space junk has been brought into focus by a research team from the University of Michigan. Space debris, consisting of remnants from rocket launches, spacewalks, and obsolete satellites, has been a growing concern in the scientific community.

Currently, only objects larger than a softball, which constitutes less than 1% of the nearly 170 million pieces of space junk, are trackable. This limitation has driven researchers to seek more effective methods for detecting smaller debris.

Current space debris detection methods

As explained by Nilton Renno, the principal investigator and a professor at the University of Michigan, the existing methodology relies on detecting objects that reflect light or radar signals. However, this technique struggles with smaller objects, as the reflected signals are too weak to be identified from the ground.

“Right now, we detect space debris by looking for objects that reflect light or radar signals,” said Nilton Renno. “The smaller the objects get, the harder it becomes to get sunlight or radar signals strong enough to detect them from the ground.”

The innovative approach proposed by this team aims to track debris as small as one millimeter in diameter. This method, capable of detecting objects similar in thickness to pencil lead, marks a significant advancement in space debris monitoring.

Dangers of space junk

Space debris poses a severe risk to satellites and spacecraft. Traveling at around 22,000 miles per hour, even small debris can cause significant damage, akin to a highway car crash.

The growing clutter in Earth’s orbit, exacerbated by collisions that create smaller, undetectable fragments, highlights the urgent need for improved tracking methods.

Mojtaba Akhavan-Tafti, an assistant research scientist and project lead, explains the proposed detection technique. It involves identifying the electric bursts produced when small debris pieces collide, vaporizing into charged gas and creating lightning-like energy bursts. These bursts, along with subsequent electric field pulses from charged solid debris fragments, are brief but detectable.

“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 Akhavan-Tafti.

Simulations and future experiments

According to recent computer simulations, collisions between aluminum pieces at orbital speeds produce detectable electrical bursts. This is strong enough for a 26-meter dish with a high-quality radio receiver to detect from the ground.

The team is planning further simulations and real signal measurements with NASA’s Deep Space Network. Additionally, they aim to analyze data from hypervelocity experiments at the Naval Research Laboratory and NASA’s Ames Research Center.

If successful, this method could not only locate space debris but also determine its composition and physical characteristics. Akhavan-Tafti emphasizes the importance of discerning whether an object is hard or soft, impacting both its orbit and potential for damage.

“We want to know if an object is hard or soft because that will impact how it orbits and how damaging it can be,” Akhavan-Tafti said.

In summary, this novel approach to detecting minuscule space debris represents a significant leap forward in ensuring the safety and longevity of our space infrastructure. With the potential to revolutionize how we monitor and manage space debris, this research could be pivotal in safeguarding vital satellite and spacecraft operations.

The full study was published in the IOC.

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