The blazing trail across the night sky was most likely one of the rocket's stages burning up as it re-entered Earth's atmosphere, he added.

“The upper stage would have gone up and deployed the satellite and then performed a deorbit burn. They would have targeted coming in over the sea — one would hope — but it's a fine art trying to get it right. If there's an issue with the motors or something, it can be a bit unpredictable when and where it comes in.”

Debris from rocket launches usually burns up rapidly on re-entry as a result of the extremely high temperatures that develop as the speeding object encounters atmospheric drag.

Re-entries can be uncontrolled, such as with space debris, or controlled in the case of reusable spacecraft, such as the now-retired US space shuttle.

On February 1 2003, the space shuttle Columbia broke up soon after re-entering the Earth's atmosphere. The shuttle was travelling at a speed of more than 23,000km/h when it began breaking up about 64km above the Earth's surface, killing all seven crew members. 

An investigation determined that tiles on the spacecraft's heat shield had been damaged during the launch days earlier, allowing heat to destroy the craft's wing structure which then failed in-flight.

Previously, the most alarming incident of human-made debris colliding with Earth occurred in 1979 when the 77-ton US Skylab space station fell out of orbit and disintegrated on re-entry, spreading debris across the Australian outback. There were no crew aboard at the time.

“That was a really big one,” said Cunnama. “You need the parts to be quite big for them to hit the ground.”

Cunnama noted that while the chances of large space debris such as asteroids impacting the earth were a possibility, this was unlikely in the very short term.

“We are tracking most of the largest objects in the solar system,” he said. “We're pretty confident that 99% of the asteroids [bigger] than 100m that we have detected do not have a dangerous path in the next 100 years or so. Those are the real civilisation-destroying asteroids, but we're not expecting one of them any time soon. But, of course, one could pop out from behind the sun at any point.”

There was a sliding scale, with smaller rocks entering Earth's atmosphere more frequently.

“There are shooting stars on any given night. Those are small, maybe a few centimetres across,” he said.

Bigger asteroids were expected once a year or even less often, he added. 

While there was a lot of debris in the solar system, it was all orbiting the sun.

“The planet has also swept a pretty clear path over the years,” he said. “And Jupiter protects us from a lot of the bigger rocks because it disturbs their orbit and they are more likely to crash into Jupiter than us.”

Meanwhile, the China Aerospace Science and Technology Corporation (Casc) announced that it launched three experimental satellites into preset orbit on Tuesday.

The satellites, which were designed and built at the China Academy of Space Technology, blasted off aboard a Long March-2C carrier rocket from Jiuquan Satellite Launch Centre in northwestern China at 7.15pm, it confirmed.

Casc said the satellites would be used to “test communications technologies”.

Quelle: TIMES Live

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Update: 26.08.2021

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‘Meteor’ most likely re-entry of Chinese rocket – expert

[VIDEO] The ball of light lit up the sky on Tuesday evening at around 18:20 and was visible across South Africa and even as far a field as Zimbabwe and Botswana.

POLOKWANE – According to unconfirmed reports, a ‘meteor’ sighting on Tuesday evening has now been said to be the reentry of the Chinese Yuanzheng-1S rocket.

The ball of light lit up the sky on Tuesday evening at around 18:20 and was visible across South Africa and even as far a field as Zimbabwe and Botswana. 

Daniel Cunnama, Science Engagement Astronomer at the South African Astronomical Observatory (SAAO) said in a tweet this morning that the sighting was ‘most likely’ the upper stage of the Chinese Yuanzheng-1S rocket being deorbited. 

Residents who witnessed the sighting said the ball appeared out of no where and shot across the sky leaving a trail of fiery debris. 

 

People took to social media to share their experience.

https://www.facebook.com/lynnette.maritz.1/videos/379250606922416/

 

 

 

 

 

Quelle: Review POLOKWANE Observer

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South Africans Spot Massive Shooting Star, Meteorite or Space Debris Over Pretoria

South Africans Spot Massive Shooting Star, Meteorite or Space Debris Over Pretoria. Photo: Twitter

Social media was abuzz in South Africa on Tuesday evening with sightings – including video and photographs – of what many thought was a meteor. The bright light flying through the air was seen above Pretoria, as well as other parts of the country, including Limpopo. In fact a former politician (David Coltart) in neighbouring Zimbabwe even filmed a sighting in Bulawaya (and someone else got a great video in Chirundu).

AfriForum’s Ernst van Zyl captured some footage in Pretoria. He said: “A massive meteor-like object just passed over Pretoria. Holy shit. Just took this footage from my house. Never seen anything like it.”

According to some experts it was not a meteorite. SA Astronoimical Observatory science engagement astronomer Daniel Cunnama, said it was a single object, not a meteor shower, and most likely a large shooting star, also known as a bolide. He tweeted: “Very impressive bolide over Pretoria this evening!”

Other experts – including US astrophysicist Jonathan McDowell – said it was space debris making a re-entry. According to Aerospace, payload from a Cape Canaveral launch on 24 October 2020 (Mission Starlink Launch 14) was expected to make a reentry tonight.

US astrophysicist Jonathan McDowell said it “looks like it was probably the Yuanzheng-1S upper stage being deorbited”, although it was over an hour earlier than expected. He later tweeted: “If I assume that the YZ-1S stage made a deorbit burn at about 1230 UTC to an orbit around 100 x 1100 km but it failed to reenter at first or second perigee, surviving to the third perigee, I get a good match with the time and location of the observations.”

Space Geek ‘Mother of all Launches’ said: “I can confirm it is from the CZ-2C launch.”

After a brief analysis of the footage, one computer scientist said: “The object appears to have originally been in low earth orbit and had its orbit decay to instability. The bright visible parts are the most damaged parts of whatever it is. What’s strange is usually natural rock continues to break apart.”

According to Pretoria Rekord, Cunnama estimates the burning object was between one to five meters big when it entered the atmosphere. He said: “There is a very small chance of some of this material hitting the ground and we will look into that. There are teams that will look if there was any chance of anything hitting the ground.” Apparently objects like this hit parts of the world five to 10 times annually.

A report in the Far North Bulletin claimed it may have crashed into the Serala mountainside in Limpopo, and that emergency services were tending to flames, however it was not certain if the fire began before the object was sighted or not.

UPDATE 25 AUG: Gauteng Weather has confirmed: “BREAKING: Tuesday evening’s ‘meteor’ over parts of Southern Africa now believed to be re-entry of Chinese Yuanzheng-1S Rocket, with number of SA groups agreeing with astronomer Jonathan McDowell’s theory. US military data shows Flag of China launched 2 internet demo & 1 unknown payload.”