This visualization shows the 18,120 objects being tracked in low-Earth orbit by the U.S. military's Joint Space Operations Center — including nearly 13,000 that are classified as space debris.

Expand chart Data: Space-Track; Note: Perigee is the point in a object's orbit where it is closest to Earth. Chart: Lazaro Gamio/Axios

Why it matters: As space opens up to more nations, companies and possibly nonprofits, concerns are growing about how to track and reduce debris that threatens satellites and spacecraft.

"The magnitude of the problem is unquantified. We can’t put a solid risk on it [for satellite operators]. But we all know it is only going to get worse."

— Moriba Jah, University of Texas at Austin

"There's a lot of ambiguity about what is up there and where it will be an hour from now, tomorrow or next week," says Jah, who's building a database in hopes that it will lead to "[global] rules of the road for good behavior" in space.

Two challenges: Jah says the resolution for tracking objects is currently on the order of kilometers, and "most of the things up there aren’t transmitting their information."

The bigger picture: The military's public database "account[s] for only 4% of the objects in space, according to AGI, a company which provides software to commercial and government entities to analyze and track objects," per CNBC.

Notable: 2,842 of the roughly 3,800 objects in low-Earth orbit associated with China are from Fengyun 1-C, a weather satellite launched in 1999. China used it as a target for a missile test in 2007, spewing fragments throughout space.

The details: In low-Earth orbit, the overwhelming majority of objects are pieces of satellites, rocket bodies and boosters, and other human-made objects-turned-debris. And that doesn't include bits and pieces that are too small to track but are still potentially damaging.

"Going forward, rules for safe, sustainable and secure space orbiting are going to be key for all operators, whether you are big or small. Orbital debris does not discriminate!"

— Saadia Pekkanen, University of Washington

What's being done to try to address the issue:

Rocket Lab, a launch company, sends the second stage of their rockets into highly elliptical orbit so it can be brought back down and burned up quickly in the atmosphere, says CEO Peter Beck.

Matt Desch, CEO of Iridium, which in 2009 lost a satellite in its constellation to a defunct Russian satellite, has called for policies that require satellites above a certain altitude to be equipped with propulsion so they can be controlled and for a retirement plan for de-orbiting satellites at the end of their run.

In July, President Trump signed a directive to develop new guidelines for satellite design and operation and for expanded tracking of space junk.

Meanwhile, researchers are experimenting with systems to net or harpoon debris.

The data: Space-Track.org is a collection of data from the Joint Space Operations Center, which tracks objects orbiting Earth in order to screen for potential collisions.

Go deeper: Business Insider's Dave Mosher writes on the threat posed by space junk.

Editor's note: This story has been updated to reflect the most recent debris data (as of Oct. 4, 2018) and to include measures being taken by industry and government to address the issue. It was first published on April 19, 2018.