There’s some interesting fallout from the recent dive of the European Remote Sensing satellite, or ERS-2, to Earth.
ERS-2 studied our planet for nearly 16 years after its launch in April 1995. Later in 2011 European Space Agency (ESA) decided to end the mission of the radar-carrying spacecraft. The agency commandeered a series of deorbiting maneuvers that lowered the satellite’s average altitude and reduced the risk of collision with other satellites. space debris.
The spacecraft was also “passivated” to reduce the risk of disintegration. Passivation involves getting rid of internally stored energy, such as venting unused propellant and discharging batteries (which can cause explosion if left charged).
“No interference can be made from the ground, so ERS-2 will return completely naturally – now a common occurrence due to average spacecraft reentry earth atmosphere The ESA’s pre-autumn statement explained: The term “return in a completely natural manner” is probably a user-friendly alternative to “uncontrolled”.
Relating to: The largest spacecraft to fall uncontrollably from space
After the fall
ESA’s Space Debris Office predicted that ERS-2’s re-entry would occur on February 21 at 10:41 EST (1541 GMT). In reality, the vehicle dived approximately two hours later and re-entered the atmosphere over the North Pacific Ocean.
The European Space Operations Center (ESOC), which hosts the engineering teams controlling the spacecraft in orbit, noted that the previous estimate came with a value of plus or minus 1.44 hours.
Yet in the business of uncontrolled space debris, minutes, even seconds, count. These could be the difference between a pile of space junk falling into isolated ocean waters and crashing into a populated area.
In fact, it is likely that parts of the 2.5-tonne ERS-2 survived the fiery reentry. ESOC media relations officer Simona-Elena Nichiteanu said that on average, 10% to 20% of the mass of larger objects passes through the atmosphere and hits the ground or water.
Before ERS-2 crashed, Nichiteanu told Space.com that the largest and heaviest scraps that would survive relatively intact were the four spacecraft tanks, three internal panels supporting the spacecraft instruments, and the antenna structure for the satellite’s Synthetic Aperture Radar antenna. The largest piece, assuming it doesn’t fall apart.
But given its reentry location, we’ll likely never know how much of the bus-sized ERS-2 survived.
In the statement made by ESA after the fall of ERS-2, “No property damage was reported.”
Relating to: The doomed large moon seen from space as it tumbled towards a fiery re-entry on February 21 (photos)
Willy-nilly satellite falls
However, a satellite that goes out of control will inevitably fall. is The reason for the willies.
This is the view of Ewan Wright, PhD. candidate at the University of British Columbia and assistant member of the Outer Space Institute. It actively focuses on the sustainability of the outer space environment.
Wright told Space.com that in the future, all large satellites should make controlled reentry.
“Operators must control them for re-entry into the oceans, away from people, aircraft and ships,” Wright said. “ERS-2 re-entered the North Pacific. If it had re-entered half an hour earlier, it could have hit Europe or Africa,” he said.
Wright noted that air traffic was seen in the North Pacific between Asia and North America and to Hawaii.
“Luckily the planes were not affected this time,” he said. “Even if planes don’t hit space debris, the uncertainty could cause airspace closures and routes to change, costing airlines and passengers.”
Given how fast objects in orbit are moving, there’s ship traffic to worry about, not just in the final reentry zone. Fragments of disintegrated satellites may fall over a wide area of the objects’ reentry orbit.
According to cruiseradio.net, it was originally reported to be an alert about the ERS-2 wreckage directed at the Princess Cruises ship carrying 2,200 passengers. The Island Princess ship was informed by a coordinated message from ESA and the National Hydrographic Office that ERS-2 could crash in the area where the pleasure boat would pass on its way to the Port of Mauritius. The Island Princess took a different route and moved away from the area.
The bottom line, according to Wright: “To reduce injury risks, we shouldn’t rely on luck. Instead of rolling the dice, operators should use controlled re-entry, directing satellites to re-enter away from people and aircraft.”
global standard
Darren McKnight is a senior technical member of LeoLabs, a commercial provider of space domain awareness services and low earth orbit The mapping is based in Menlo Park, California.
The likelihood of casualties on the ground in a single reentry is low, McKnight said. However, the total risk increases over time.
“It’s not a question of ‘when’ but a question of ‘when’ an abandoned object will survive on the Earth’s surface and cause significant damage, death or injury,” McKnight told Space.com.
When that fateful day comes, there will be an uproar over uncontrolled satellite intrusions, McKnight said. He added that the “global standard” is the 25-year rule, meaning that each satellite must be deorbited within 25 years of the end of its mission.
“But the United States is the only country that requires operators to minimize the risk of loss of people on site from reentry,” McKnight said. “This will evolve as the 25-year rule evolves into a five-year rule that is currently only required by the Federal Communications Commission.”
old rules
On the other hand, McKnight said, we’ll have decades of reentry based on outdated rules. What’s more, he said, most of the orphaned mass currently in orbit consists of objects launched in the 1980s and 1990s, when there were no mitigation rules.
The slower the regulations evolve, the more complicated it will be to determine their benefits because of the variety of hardware available in orbit, McKnight said.
“I also think it’s interesting that some people are now concerned about contamination of the atmosphere, as regulations have pushed operators to design spacecraft to be destroyed and have them break up on re-entry. from space launch waste and re-entry of the disintegrated spacecraft,” McKnight noted.
According to McKnight, this becomes more complicated as the amount of material increases. “No one will be happy!” said.
hot topic
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Leonard Schulz, a researcher at the Institute of Geophysics and Extraterrestrial Physics at the Technische Universität Braunschweig in Germany, said dead satellite falls like the one in ERS-2 occur fairly regularly.
Schulz told Space.com that such re-entry will only increase in the future due to the increasing number of objects being brought into low-Earth orbit. Additionally, it is necessary to take into account: Effects of spacecraft reentry on the atmosphereIt is a hot topic that ESA is also considering.
“Today, we lack knowledge on many issues regarding the materials released and their impact on the atmosphere,” Schulz said.
Schulz advised that satellite reentry is a good opportunity to collect data through measurement campaigns. But uncontrolled reentry like that of ERS-2 is extremely difficult to observe because the level of uncertainty about where the satellite actually reentered is so high, he said.
“But controlled re-entries provide great measurement opportunities,” Schulz concluded, “and this should be a focus in the future!”