Waste in space: Why junk in Earth orbit is becoming a huge problem

Who knew space could get crowded? Junk is filling the space above Earth.

In recent weeks, some of that junk has made its way back.

In January 2021, astronauts at the International Space Station pitched a pallet of used lithium-ion batteries over the side to free up some room after NASA determined it would "harmlessly reenter the Earth’s atmosphere," according to Ars Technica.

Three years later, on March 8 of this year, a nearly 2-pound chunk of it may have torn through the roof and two floors of a man's house in Naples, Florida.

 On April 2, large fiery streaks of light appeared over a wide area over Los Angeles. It turned out to be space debris, part of a Chinese spacecraft, according to the U.S. Space Command. 

What is space junk? We explain: 

There are various types of space junk

Space junk basically is any machinery or debris left in space by humans.

Items range in size from large objects such as failed or dead satellites to tiny objects such as paint flecks and nuts and bolts. 

Types of debris include:

• Rockets: Portions of the rocket stages used in launches and discarded in low Earth orbit.
• Payload: Satellites that have reached the end of their operational lives.
• Mission-related objects: Items such as hand tools, screws and nuts and bolts. One example is a tool bag that drifted away during a spacewalk in December 2023. 

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Since the beginning of space exploration in 1957, the North American Aerospace Defense Command (NORAD) has collected data on space debris. It tracked Russia's first satellite, Sputnik, which launched the same year. Since then, NASA, the U.N. Office for Outer Space Affairs and the European Space Agency have tracked thousands of objects orbiting Earth.

NASA estimates 17.6 million pounds − or 8,800 tons − worth of objects are in Earth orbit, according to its most current Orbital Debris Quarterly News. And the number of small satellites is expected to increase.

About 44 tons of space debris falls into Earth’s atmosphere each day. About 95% of it burns up. 

Where do you find space junk?

Space junk typically circles the planet in low Earth orbit, or within 1,200 miles of Earth's surface. Orbits are classified in three basic categories: 

• High: Most weather and communications satellites, farthest from the planet's surface.
• Medium: Navigation and specialized satellites, intended to observe a specific area.
• Low: The majority of research satellites, such as the fleet of NASA's Earth Observing System.

There are 9,777 objects circling Earth, the majority of which are in low Earth orbit, according to the satellite tracking website Orbiting Now. 

Why is space junk dangerous?

There are roughly 100 million debris fragments larger than 0.04 inches in size and about 23,000 particles larger than 4 inches in orbit.

Debris can travel at 18,000 mph, according to NASA. That's 10 times faster than the speed of a bullet, so even a tiny paint chip can rupture a spacesuit or damage delicate solar arrays and electronics on a satellite.

Future and current missions can be at risk of debris strikes. There are drawbacks to maneuvering a satellite to avoid space junk: the satellite may end up in a less efficient orbit.

How does junk get into space?

Countries that launch objects into space contribute to debris. 

Since 1957, the U.S. has launched 9,632 objects into space, according to Our World in Data. The U.S. accounted for the majority of satellites launched into orbit last year. 

Number of launches in 2023: 

• U.S. 2,166 
• United Kingdom 144
• China 128
• Russia 62
• Luxembourg 12

What’s the risk of being hit by a piece of falling space debris? 

Your risk of being injured by falling space debris is less than 1 in 100 billion, according to the European Space Agency. 

That means you have better odds of winning a Powerball jackpot of any amount, at 1 in 292 million. 

Though that's not zero, your chances of being hit by a falling satellite are 65,000 times lower than the risk of being struck by lightning and three times lower than the risk of being struck by a meteorite, ESA says. 

CONTRIBUTING George Petras and Emily DeLetter, USA TODAY, C.A. Bridges and John Tufts/USA TODAY NETWORK

SOURCE NASA Orbital Debris Program Office, NASA Jet Propulsion Laboratory, Our World in Data, The United Nations Office for Outer Space Affairs and European Space Agency