Former NASA astronaut Leroy Chiao explains what happens when a dead satellite makes a "natural" re-entry to Earth. European Space Agency's ERS-2 satellite is expected to come crashing down this week.
A defunct European Space Agency satellite the size of a school bus will come crashing down to Earth on Wednesday, more than a decade after the spacecraft finished its mission observing Earth's systems and natural disasters.
ESA's first advanced Earth-observing satellite, the ERS-2, launched on April 21, 1995. After studying Earth's land, oceans and polar caps for 16 years, ESA opted to end its operation in 2011 and deorbit the satellite to prevent the creation of more space debris.
Early Wednesday, the re-entry track placed the satellite over the Pacific Ocean, possibly off the West Coast of the U.S. However, about an hour later, the space agency released an updated track with the satellite coming down over the Norwegian Sea, off the coast of Norway.
ESA said the re-entry window opened around 9 a.m. EST. As of 11:45 a.m., the satellite was about 30 minutes from re-entry but the situation is still developing.
"It is here that we currently expect the satellite to begin to break up," ESA said of the latest re-entry estimate. "The vast majority of the satellite will burn up, and any pieces that survive will be spread out somewhat randomly over a ground track on average hundreds of kilometers long and a few tens of kilometers wide (which is why the associated risks are very, very low)."
NASA, ESA and other international aerospace community members have guidelines to reduce dead satellites and rocket parts in low-Earth orbit by requiring post-mission disposal of natural decay or a controlled entry.
"Most people nowadays and for the past several years have designed their satellites responsibly to be disposed of, responsibly and in a controlled manner," former NASA astronaut Leroy Chiao told FOX Weather. "At the end of life, spacecraft may do a deorbit burn to try to target what we call the spacecraft or satellite graveyard in the Indian Ocean, far away from shipping lanes, far away from any human activity."
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For ERS-2, mission control sent a series of commands to the 38-foot-tall satellite to lower its altitude over 66 maneuvers until it was in a passive orbit.
The large satellite was recently spotted in late January and early February descending through Earth's atmosphere by other spacecraft in orbit. The ESA said images from HEO, an Australian company, were taken for the UK Space Agency showing the ERS-2 satellite tumbling through the atmosphere.
ESA’s ERS-2 satellite was spotted on January 29, 2024, tumbling as it descends through the atmosphere. These images were captured by cameras on board other satellites by Australian company HEO on behalf of the UK Space Agency.
(HEO)
"The UK Space Agency recently worked with HEO to capture these images of ERS-2 during its descent," the ESA said. "Using cameras on other satellites to image objects reentering the atmosphere is a relatively new approach. In the future, these images may be used alongside data from ground-based sensors to refine reentry predictions."
A day before re-entry was expected, the satellite was spotted zooming over Rome, Italy, by ESA's Earth Observation Center.
When will the satellite fall toward Earth?
Over nearly 13 years, the satellite has naturally descended from its orbit about 350 miles above Earth until our planet's gravity pulls the spacecraft down and burns up in the atmosphere.
The ERS-2 satellite re-entry timeline. (Image: ESA)
(ESA)
Since the spacecraft took a "natural descent" path, ESA could not predict precisely when or where the satellite would come down on Earth but estimated it would happen in February 2024. As the satellite's demise approaches, ESA has been issuing updates.
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ESA's Space Debris Office released its latest re-entry prediction on Wednesday, saying the satellite will likely burn up over Earth's atmosphere on Wednesday morning plus or minus a margin of about 30 minutes. The landing and re-entry location uncertainty will decrease as the spacecraft's end nears.
ESA said that at about 50 miles above Earth, the large satellite will break up into small pieces. Any risks from the satellite reentry are very low, according to the space agency.
"It's expected that it will either all burn up, or maybe a few small pieces might survive the reentry into the Earth's atmosphere. But it's really not a cause for concern," Chiao said. "The calculated odds by the European Space Agency is about one and 1.5 billion, that some individual would be affected by this."
ESA's Space Debris Office continues to post timing updates.
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