Space junk: What happens to the ISS battery pack and where it ends up

Space junk
ISS battery pack falls to Earth – “perhaps as a beautiful shooting star”

Experts stick to their assessment and look at the falling debris of a discarded battery pack from the International Space Station In all likelihood, ISS is not a threat to Germany. It is unlikely that parts will fall over Germany, a spokesman for the German Aerospace Center (DLR) told the German Press Agency on Friday morning. According to current calculations, the object could enter the atmosphere over northern North America. The time window specified was a 20-hour corridor around late Friday evening German time.

The Federal Office for Civil Protection and Disaster Assistance (BBK) had disseminated official danger information on Thursday afternoon via several warning apps, according to which the probability of rubble falling on Germany was very low. “If the risk increases, you will receive new information,” it said. However, “luminous phenomena or the perception of a sonic boom” are possible.

“Initial analyzes by the German Space Situational Center have shown that parts of the battery packs can survive re-entry and reach the earth’s surface,” the Aerospace Center announced on Thursday. Before re-entry, the object flew over Germany several times, but a threat in this country is “currently viewed as statistically unlikely.” The Federal Ministry wrote that a threat to Germany was “very unlikely.”

It further announced: “If, contrary to expectations, there are indications that Germany is affected, the existing crisis response mechanisms of the federal and state governments will be used to respond appropriately to a possible threat. However, based on the current status, this is more than unlikely. Nevertheless, it will Object closely monitored.”

This is how experts assess the danger

Europe’s former space chief Jan Wörner also believes the danger is low. “Batteries really like to burn. I assume that the package will almost completely burn up in the atmosphere,” said the former president of the European Space Agency (Esa) to the German Press Agency. “Maybe you’ll see the disassembly as a beautiful shooting star.” Even if particles got through, a hit on an inhabited area is unlikely. “There is a lot of water under the large area that the package flies over.”

The German astronaut Alexander Gerst described letting it burn up as sensible. “This is the best way to avoid space debris. This is, in principle, a positive thing,” said Gerst on Thursday in Washington, where he and his colleague Matthias Maurer accompanied Federal Economics Minister Robert Habeck (Greens) to speak in the US Capital to discuss cooperation between Americans and Europeans, for example on future moon missions.

Why does the Federal Office for Civil Protection still warn?

On star-Inquiry, a press spokesman writes: “The intention by sending the message was to create transparent information about the space event and to provide information about the currently estimated trajectory. This danger information does not change the current assessment that there is currently a danger to Germany is considered statistically unlikely.” The message was sent with the lowest warning level.

What kind of object is it?

The object is said to be a platform with battery packs that is about the size of a car and weighs 2.6 tons – the largest object to have been dropped from the ISS to date. The platform was deliberately separated from the ISS on March 21, 2021, only to enter the atmosphere and burn up years later.

Why can’t re-entry and possible debris crashes be predicted exactly?

It is an uncontrolled re-entry, so precise predictions are very difficult. “The object is gradually slowed down by the atmosphere and thus loses its orbit,” said the head of the ESA space security program, Holger Krag, to the online portal of the “Tagesschau”. “The great uncertainty comes from the fact that we cannot predict exactly how dense the atmosphere will be. It depends on many factors and is largely left to chance. In this respect, even a few hours in advance, you cannot precisely determine the location “You may be able to exclude some continents, but you definitely can’t narrow the forecast down to one country or one city.”

How does a re-entry work?

“It happens very quickly,” Krag said of entering the atmosphere. “It only takes ten minutes from an altitude of 100 kilometers, where re-entry takes place when the object begins to disintegrate, to the ground. However, the battery block will not fall as a compact individual part in a very narrow area, but will be distributed “It’s more likely to be a longer trail of debris. You would expect a smaller piece every 10 or 20 kilometers in the affected area.”

The experts can use radars to determine that the object is no longer traveling in space. It is also possible for light trails to be observed in the sky and perhaps captured by photo or video.

Does something like this happen often?

It is common practice for space debris to enter the atmosphere and burn up there. Just a few weeks ago, the European satellite “ERS-2”, which was launched almost 30 years ago, came to such an end and was destroyed as planned. It also happens again and again that smaller debris reaches the earth’s surface. They usually fall over the ocean or uninhabited areas. According to the US space agency NASA, an average of one known piece has fallen to Earth per day over the past 50 years. So far, no serious injuries or significant material damage have been reported as a result.

According to the US space agency Nasa, there are currently more than 25,000 objects with a circumference of more than ten centimeters in space, around 500,000 with a circumference between one and ten centimeters and more than 100 million particles that are larger than a millimeter. In total there are more than 9,000 tons. The main causes are satellite explosions and collisions.

Are there efforts to do something about space debris?

Many countries active in space have expressed concern and have advocated reducing the creation of further space debris as much as possible – for example by appropriately designing spaceships and satellites. Former Esa boss Wörner also called for “finally an early warning system to protect the earth”.

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DPA