NASA Satellite Falls Back to Earth After Almost 40 Years in Space

After more than 38 years orbiting Earth, NASA’s Earth Radiation Budget Satellite (ERBS) has returned home.

The craft reentered Earth’s atmosphere over the Bering Sea at 11:04 p.m. Eastern time on Sunday, NASA says in a statement. The agency anticipated that most—but not all—of the satellite would burn up as it sped through Earth’s atmosphere. While the return of ERBS calls attention to the mission’s success, its reentry has put a spotlight on the dangers of space debris.

The 5,400-pound ERBS satellite launched on October 5, 1984, from the space shuttle Challenger. Originally intended to operate for two years, the satellite outlived that goal and gathered data for 21 years, until 2005.

ERBS provided insights into global warming and weather patterns. Two of its instruments measured Earth’s radiation budget—the balance of energy from the sun that’s absorbed by Earth versus reflected or radiated back to space. Data from ERBS revealed how human activities, such as using ozone-eating chemicals called chlorofluorocarbons (CFCs) and burning fossil fuels, impact this delicate balance.

The satellite’s third instrument studied the makeup of the stratosphere, including levels of water vapor, nitrogen dioxide, aerosols and ozone, a gas that protects life on Earth by absorbing ultraviolet radiation from the sun. As a result, ERBS helped confirm that the Earth’s ozone layer was thinning.

In this way, the satellite played a role in shaping the 1987 Montreal Protocol, which phased down the use of close to 100 human-made ozone-depleting chemicals. Nearly 200 countries signed the agreement, and it led to a dramatic decrease in the use of CFCs, writes CNN’s Katie Hunt. A recent United Nations assessment found that the hole in the ozone layer over Antarctica is on track to fully recover by 2066.

ERBS did not cause any reported damage or injuries, but before it reentered Earth’s atmosphere this week, NASA estimated the chances of its debris harming anyone were 1 in 9,400. That’s slightly more dangerous than the current standards, which require the odds of orbital debris killing a person to be less than 1 in 10,000. But ERBS was launched well before the current practices were set in 2019.

Last year, the U.S. Federal Communications Commission adopted new rules requiring satellite operators to deorbit satellites within five years of completing their missions. This would reduce the amount of space junk in orbit and decrease the risk of collisions, per Gizmodo’s George Dvorsky.

The risks posed by space junk and falling debris have been a topic of discussion in the space community of late. In less than three years, China has launched four rockets that have fallen uncontrolled back to Earth, the Washington Post’s Christian Davenport wrote in November. Other countries and companies guide rockets into the ocean or land them softly, per the publication.

While no deaths from falling rockets have ever been documented, a research paper published in July in Nature Astronomy estimated there is a 10 percent chance of a falling rocket piece killing at least one person over the next decade.

Remains from ERBS probably fell in the ocean or a remote part of Alaska and therefore will likely never be recovered, writes Forbes’ Eric Mack.

Will Sullivan | | READ MORE

Will Sullivan is a science writer based in Washington, D.C. His work has appeared in Inside Science and NOVA Next.