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Today — May 9th 2021Your RSS feeds

China’s Rocket Body: Reentry Reactions

  China’s Long March-5B big booster stage made a fiery reentry to Earth. The U.S. Space Force’s 18th Space Control Squadron (SPCS) at Vandenberg Air Force Base, California confirmed the rocket stage reentered Earth’s atmosphere on May 9 and fell into the Indian ocean north of the Maldives. The Maldives National Defence Force (MNDF) has […]

China’s Rocket Body: Reentry Reactions

  China’s Long March-5B big booster stage made a fiery reentry to Earth. The U.S. Space Force’s 18th Space Control Squadron (SPCS) at Vandenberg Air Force Base, California confirmed the rocket stage reentered Earth’s atmosphere on May 9 and fell into the Indian ocean north of the Maldives. The Maldives National Defence Force (MNDF) has […]

‘Irresponsible’: Nasa chides China as rocket debris lands in Indian Ocean

May 9th 2021 at 07:28

US agency accuses Beijing of failing to meet expected standards regarding its space debris

Remnants of China’s biggest rocket have landed in the Indian Ocean, ending days of speculation over where the debris would hit and drawing US criticism over a lack of transparency.

The coordinates given by Chinese state media, citing the China Manned Space Engineering Office (CMSEO), put the point of impact west of the Maldives archipelago.

Related: Chinese rocket’s chaotic fall to Earth highlights problem of space junk

Continue reading...

Remnants of CZ-5B rocket fell into the Indian Ocean

09 May 2021
The remnants of China’s CZ-5B (Y2) rocket re-entered the atmosphere at 10:24 BJT (02:24 UTC) on 9 May. The parts surviving the re-entry fell into a sea area with the center at 2.65° North and 72.47°East, said CMSA. tweeted that the 18 Space Control Squadron confirmed the remnants of the Long March 5B rocket had fallen into the Indian Ocean north of the Maldives.
No immediate reports of any damage or casualties became known, ending an anxious week as people and governments wondered where and when the space debris would fall.

China Satellite Network Group - a new, special entrant to the world of satellite constellations

09 May 2021
China Satellite Network Group, founded in April with a ceremony attended by Chinese Vice-Premier Han Zheng, is tasked with launching low Earth orbit (LEO) satellites into space, beaming internet services to anywhere on the planet. The newcomer reports to the Assets Supervision and Administration Commission, which controls the Chinese government’s stakes in state-owned companies.
The company has no official website at the moment, and the government has yet to release any information about the firm’s organisational structure - except that Zhang Dongchen, former general manager at state-owned China Electronics Corporation, was appointed to oversee its establishment.

It’s Official, Astronaut Bill Nelson is NASA’s new Administrator

May 9th 2021 at 03:41

On March 19th, 2021, the Biden Administration announced that they had nominated a successor for the role of NASA Administrator. Their nominee was Sen. Clarence William Nelson II (aka. Bill Nelson), a Democratic Senator from Florida, an attorney, and a former payload specialist at NASA. On Monday, May 3rd, he assumed the role of 14th NASA Administrator during a ceremony where he was given the oath of office.

Harris, who recently took over as chair of the National Space Council (NSC) from outgoing VP Mike Pence, delivered the oath to Nelon during a ceremony at the VP office in the Eisenhower Executive Office Building (EEOB). They were joined via video conference by former administrator Bridenstine and in-person by Nelson’s family and Charles F. Bolden – who served as NASA Administrator from 2009 and 2017.

“Congratulations, Mr. Administrator, for all the work you’ve done and all you’ve dedicated to our country,” said Vice President Harris. “I couldn’t agree more that this has to be about our nation and what is best for our nation, unencumbered by partisan politics, but based on what we know is the right thing to do.”

Senator Bill Nelson at the ceremony where Nelson was sworn in as the 14th NASA Administrator. Credit: NASA/Aubrey Gemignani

In a speech delivered after he took the oath, Nelson said:

“It’s an honor to be sworn in by Vice President Harris to serve as NASA administrator, and I look forward to a continued, strong relationship with her as chair of the National Space Council. I want to thank Steve Jurczyk for his leadership as Acting Administrator over the past few months, helping to carry out the Biden-Harris Administration’s priorities and ensure the success of NASA’s goals and missions. You’ve seen the incredible accomplishments at NASA over the past 100 or so days – the proof is in the pudding.”

The NSC was reactivated in 2017, the announcement of which coincided with the unveiling of the Trump administration’s space policy (which emphasized a return to the Moon). The NSC was originally founded in 1958 with the passing of the National Aeronautics and Space Act, which called for the creation of NASA and established the National Aeronautics and Space Council (NASC) – later renamed the NSC.

Also in attendance was Colonel Pam Melroy, a member of the National Space Council’s Users Advisory Group, a former U.S. Air Force test pilot and astronaut, and one of only three women to command a Space Shuttle mission. Melroy was recently nominated by the Biden administration for the role of NASA deputy administrator. Nelson acknowledged her and the other attendees who have played a vital role in the continuation of NASA’s efforts in space:

“I was glad to be joined today by my rock, my wife, Grace, my children, deputy administrator nominee Col. Pam Melroy, and former NASA Administrators Charlie Bolden and Jim Bridenstine, whose standing with me symbolizes the continuity of purpose and bipartisanship. It’s an incredible time for the aerospace sector, and I’m excited to lead NASA’s workforce into an exciting future!”

Illustration of Artemis astronauts on the Moon. Credits: NASA

Nelson is eminently qualified for the role, given his extensive history with NASA and the way he has been integral to many of the positive steps taken by the agency. In 1986, Nelson flew Space Shuttle Columbia where he was the payload specialist and Charles Bolden was the pilot. As part of the STS-61C mission, Nelson conducted 12 medical experiments (including the first American space stress test) and a university-sponsored cancer research experiment.

Between 2001 and 2019, Nelson represented Florida’s 9th and 11th districts in the US House of Representatives. During that time, he distinguished himself as being the leading advocate for space programs in Congress. In 2010, he criticized the Obama administration’s decision to completely terminate Project Constellation. This program was initiated in 2005 to develop a new generation of heavy launch vehicles to replace the aging Space Shuttle.

Later that year, when the Obama administration declared its commitment to charting a new course for the future of NASA in space, Nelson and Sen. Kay Bailey Hutchinson (R-Texas) collaborated to pass the NASA Authorization Act. This landmark legislation authorized appropriations for NASA for the next three years, mandated the retirement of the Space Shuttle by 2011, and established objectives for the next two decades.

Among them was the development of the Space Launch System (SLS), the Orion spacecraft, an Asteroid Redirect Robotic Mission (ARRM) by 2021, and a crewed mission to Mars by the 2030s. In 2017, Nelson and Sen. Ted Cruz (R-Texas) authored the NASA Transition Authorization Act, which authorized transitional funding for NASA’s long-term goals and expanded their commercial activities in space. 

Former Senator Bill Nelson, speaks to media after he was ceremonially sworn-in as the 14th NASA Administrator by Vice President Kamala Harris. Credit: NASA/Aubrey Gemignani

Prior to his nomination, Nelson was a member-at-large with the NASA Advisory Council (NAC), a body made up of select citizens that provides NASA with advice and guidance on major program and policy issues. He also served as the head of the House’s Subcommittee on Science and Space for six years before becoming the ranking member on the Committee on Commerce, Science and Transportation.

Nelson was confirmed as the next NASA Administrator by the US Senate on April 29th. Said acting NASA Administrator Steve Jurczyk about the decision:

“I’m happy to welcome Bill to the NASA family. It’s been an amazing year for NASA and our commercial and international partners, and I look forward to working with Bill and the Biden-Harris Administration to build on the incredible momentum we’ve built so far. It has been an honor to serve as acting administrator, but it’s the NASA workforce that makes the agency one-of-a-kind. Thank you for all you do to advance NASA’s critical missions.”

In his new role at NASA, Nelson will be responsible for guiding the nation’s space program at a highly critical juncture. In less than three years, NASA intends to land the “first woman and next man” on the Moon as part of the Artemis Program. In the meantime, there is still much to done, which includes getting the SLS ready for launch-testing and ironing out the legal disputes over who gets to build the Human Landing System (SLS).

In addition, Nelson will oversee the expansion of climate change research, fostering innovation, and enhancing NASA’s outreach efforts to the business, research, manufacturing, and STEM education sectors. The coming years are going to be pretty turbulent as NASA grapples with multiple challenges. It’s encouraging to know that a seasoned veteran will be at the helm.

Further Reading: NASA

The post It’s Official, Astronaut Bill Nelson is NASA’s new Administrator appeared first on Universe Today.

Yesterday — May 8th 2021Your RSS feeds

Live coverage: SpaceX launches Falcon 9 rocket from Cape Canaveral

May 8th 2021 at 16:54

Live coverage of the countdown and launch of a SpaceX Falcon 9 rocket from pad 40 at Cape Canaveral Space Force Station in Florida. The mission will launch SpaceX’s next batch of 60 Starlink broadband satellites. Text updates will appear automatically below. Follow us on Twitter.

EDITOR’S NOTE: SpaceX’s live webcast begins about 15 minutes prior to liftoff. The “SFN view of pad 40” tab is streaming a live view of the Falcon 9 rocket beginning at T-minus 2 hours.

SpaceX webcast

SFN view of pad 40

SpaceX mission audio

China Rocket Stage: Live View of Reentry

The folks at CelesTrak and Digital Arsenal are providing a live view of the evolving decay of China’s Long March-5B rocket body that launched the country’s Tianhe core space station module. Using the latest data from the 18th Space Control Squadron (18 SPCS) of the U.S. Space Force, the projection shows the position of the […]

China Rocket Stage: Live View of Reentry

The folks at CelesTrak and Digital Arsenal are providing a live view of the evolving decay of China’s Long March-5B rocket body that launched the country’s Tianhe core space station module. Using the latest data from the 18th Space Control Squadron (18 SPCS) of the U.S. Space Force, the projection shows the position of the […]

SpaceX ready to break another rocket reuse record with launch early Sunday

May 8th 2021 at 11:44
A Falcon 9 rocket launches March 14 with the same booster set to fly a 10th time Sunday. Credit: SpaceX

A Falcon 9 rocket and 60 more Starlink internet satellites set for launch early Sunday at Cape Canaveral will mark the first time SpaceX has flown a first stage 10 times, reaching a milestone that the company once said could be a limit for reusing boosters. Now SpaceX plans to keep flying reused rockets on Starlink missions until one fails.

The mission Sunday is set for liftoff at 2:42 a.m. EDT (0642 GMT) from pad 40 at Cape Canaveral Space Force Station, Florida. Nine kerosene-burning Merlin 1D engines will power the Falcon 9 rocket northeast from Florida’s Space Coast, following a trail blazed by 26 previous dedicated Starlink missions.

There is an 80 percent chance of good weather for launch at Cape Canaveral, according to the 45th Weather Squadron at Patrick Space Force Base. There is also a good chance of favorable upper level winds and acceptable conditions in the Falcon 9 booster’s downrange recovery area in the Atlantic Ocean.

“The overall threat for a delay looks to be small but the main weather concern for the primary day will be from the cumulus cloud rule,” forecasters wrote Saturday.

The flight Sunday will mark the 14th launch of a Falcon 9 rocket this year, and the fourth Falcon 9 mission in just 16 days.

The booster assigned to Sunday’s launch — designated B1051 — has flown to space nine times since debuting in March 2019 with the first unpiloted test flight of SpaceX’s Crew Dragon capsule. Since then, the rocket launched three Canadian Radarsat satellites, SiriusXM’s SXM 7 radio broadcasting satellite, and six Starlink missions, most recently on March 14.

The Falcon 9 booster’s 10th launch Sunday will mark the 63rd flight of a re-flown SpaceX first stage. All of the reused rocket flights to date have been successful.

When the current version of the Falcon 9 rocket — known as the Block 5 — launched for the first time in 2018, SpaceX officials said the booster could fly 10 times before requiring major refurbishment.

Elon Musk, SpaceX’s founder and CEO, said last month that the company now plans to keep flying Falcon 9 boosters until one fails. SpaceX will take that risk on missions launching the company’s own Starlink internet satellites.

“There doesn’t seem to be any obvious limit to the reusability of the vehicle,” Musk told Spaceflight Now in a press conference April 23.

Musk said SpaceX plans to keep reusing Falcon 9 boosters until they break, likely exceeding the 10-flight milestone.

“We do intend to fly the Falcon 9 booster until we see some kind of a failure with the Starlink missions, obviously, just to have that be a life leader,” Musk said.

Since launching the first reused Falcon 9 first stage on a mission in 2017, SpaceX has cinched agreements with all of its customers to fly payloads on recycled rockets.

One of the last customers SpaceX got to agree to launch on reused boosters was NASA’s commercial crew program. SpaceX’s most recent launch with astronauts April 23 was the first commercial crew mission to take off on a previously-flown rocket.

The U.S. Space Force plans to launch a national security payload on a reused Falcon 9 booster for the first time in June.

“You probably don’t want to be on a life leader for a crewed mission, but it’s probably good to have a flight or two under its belt, for the booster to have flown once or twice,” Musk said. “If it was an aircraft coming out of the factory, you’d want the aircraft to probably have gone through a test flight or two before you put passengers on.

“So I think that’s probably a couple of flights is a good number for a crew booster, and in the meantime, we’ll keep flying the life leader,” Musk said. “We’ve got nine flights on one of the boosters. We’re going to have a 10th flight soon with a Starlink mission.”

A view of 60 Starlink satellites stacked before a previous launch. Credit: SpaceX

SpaceX has been using its fleet of Falcon 9 boosters to launch Starlink missions at an average pace of three times per month so far this year. On some of those missions, SpaceX has used reused first stages that set new records for their number of flights.

The most recent Falcon 9 launch Tuesday employed a booster making its ninth flight, tying B1051’s flight history until it makes its 10th launch Sunday.

Last year, a SpaceX manager said it costs less than $30 million to fly a Falcon 9 rocket with reused parts, such as the booster and payload fairing, the clamshell-like aero-structure that protects sensitive satellite payloads during the climb through the atmosphere.

Although SpaceX has proven it can safely reuse first stages, payload shrouds, and Dragon capsules, the Falcon 9 rocket’s upper stage remains a single-use component. None of SpaceX’s competitors in the commercial launch industry have successfully re-flown an orbital-class booster. Some companies, like Blue Origin and Rocket Lab, plan to eventually recover and reuse their rocket boosters.

Repeating a mantra he’s consistently said for decades, Musk said last week that reusing rockets is a “fundamental holy grail breakthrough” needed to revolutionize access to space.

“To make humanity a truly space-faring civilization, we must have a fully and rapidly reusable rocket,” Musk said in a webcast last month hosted by the X Prize Foundation. “We’ve made some progress in that direction with Falcon 9, where the booster is reusable, and the Dragon spacecraft — the upper portion — is reusable. But the Falcon 9’s second stage and Dragon’s unpressurized trunk are not reusable.

“And I would not say the Falcon booster, spacecraft, and fairing, they aren’t rapidly reusable,” Musk said. “It takes a fair bit of effort, much less effort than the space shuttle took.”

He said SpaceX refurbishment teams at Cape Canaveral can reduce the turnaround time between Falcon 9 booster flights to less than a month. So far, the shortest time between two flights of the same Falcon 9 booster has been 27 days.

Most Falcon 9 missions require the first stage booster to land on an offshore drone ship a few hundred miles downrange from the launch site. On some missions carrying lighter payloads, the booster has enough propellant reserved to turn around and fly back to the launch site for a landing onshore.

“Landing out to sea, and then having to bring it back, and then taking a month or so to get it ready for launch, I wouldn’t call that rapid by aircraft standards,” Musk said.

SpaceX’s next-generation Starship vehicle is designed to be fully and rapidly reusable, further driving down launch costs, according to Musk.

The first stage booster, known as the Super Heavy, will land back on the ground minutes after launch, similar to the profile pioneered by the Falcon 9 rocket. The Starship will propel itself into Earth orbit, and eventually to destinations in deep space, then re-enter the atmosphere at the end of its mission for a vertical rocket-assisted landing.

The entire Starship rocket stack will stand nearly 400 feet (120 meters) tall, with 28 methane-fueled Raptor engines on the first stage and six more Raptor powerplants on the Starship upper stage.

NASA awarded SpaceX a $2.9 billion contract April 16 to develop a derivative of the Starship vehicle to land the next astronauts on the Moon through the agency’s Artemis exploration program.

A NASA-owned Orion crew capsule launched on top of the space agency’s powerful Space Launch System rocket will transport the astronauts between the Earth and lunar orbit, where the crew will dock with the waiting unoccupied Starship to head to the surface of the Moon.

Under NASA’s flight plans, the Starship will launch the astronauts back into space to meet with the Orion capsule for return to Earth.

Despite using engines flown on NASA’s retired reusable space shuttles, each of NASA’s SLS rockets is designed for one flight. NASA plans to refurbish and reuse Orion crew capsules after splashing down at sea.

But the lunar mission is just part of SpaceX’s ambition for the Starship program. The rocket could launch massive clusters of small satellites, such as Starlink spacecraft, loft huge space telescopes, and carry large numbers of people to space. SpaceX says it can deliver payloads of more than 100 metric tons, or 220,000 pounds, or low Earth orbit.

“With Starship, we’ll hopefully reuse the whole thing,” Musk said. “This is a hard problem for rockets, that’s for sure. It’s taken us, we’re like 19 years in now. I think the Starship design can work. It’s just, it’s a hard thing to solve, and the support of NASA is very much appreciated in this regard. I think it’s going to work.”

“I’d say it’s only recently though that I feel that full and rapid reusability can be accomplished,” Musk said. “I wasn’t sure for a long time, but I am sure now.”

With the 60 satellites poised to blast off Sunday, SpaceX will have launched 1,625 Starlink internet satellites on 29 rocket flights, including 27 dedicated Falcon 9 missions. Some of those satellites are now decommissioned.

SpaceX has regulatory approval from the Federal Communications Commission to launch and operate 12,000 broadband satellites to provide high-speed, low-latency internet signals to consumers around the world. The network is already providing limited internet service to subscribers who have signed up for beta testing.

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Follow Stephen Clark on Twitter: @StephenClark1.

China’s Rocket Body: Trajectory Impact Prediction

Debris from a Chinese carrier rocket in the coming days is very unlikely to cause damage, said Wang Wenbin, a Foreign Ministry spokesman, according to a China Daily report. Regarding the atmospheric reentry of the core stage of the country’s Long March5B heavy-lift booster, Wang said it is highly unlikely that the debris will cause […]

China’s Rocket Body: Trajectory Impact Prediction

Debris from a Chinese carrier rocket in the coming days is very unlikely to cause damage, said Wang Wenbin, a Foreign Ministry spokesman, according to a China Daily report. Regarding the atmospheric reentry of the core stage of the country’s Long March5B heavy-lift booster, Wang said it is highly unlikely that the debris will cause […]

Large Chinese rocket tumbling toward toward unguided re-entry this weekend

May 7th 2021 at 19:20
A Long March 5B rocket lifts off with the Tianhe space station module. Credit: Xinhua

For the second time in a year, a large spent Chinese rocket stage intentionally left in orbit is heading for an unguided plunge back into Earth’s atmosphere Saturday or Sunday somewhere between 41.5 degrees north and south latitude.

The heavy-lift Long March 5B rocket stage took off April 28 with the Tianhe core module for China’s space station. The Long March 5B — one of the most powerful rockets in the world — tracked downrange to the southeast from the Wenchang launch base on Hainan Island, China’s southernmost province.

The launcher shed its four strap-on boosters about three minutes into the mission, but the two engines on the Long March 5B’s core stage continued firing for about eight minutes, doing all the work to place the 54.4-foot (16.6-meter) Tianhe space station module into orbit.

Most rockets have an upper stage to finish the job of deploying payloads into orbit. On those launchers, the first stage does not attain enough velocity to orbit the Earth. SpaceX recovers its first stages for reuse, while other launchers have booster stages that fall back to the ground hundreds of miles downrange from the launch site.

Many launch operators design their upper stages to reignite their engines at the end of their missions to guide the rockets to a controlled re-entry over a remote stretch of ocean. Rather than designing the huge Long March 5B core stage t0 remove itself from orbit using engines or thrusters, Chinese engineers left the rocket in space after finishing its mission.

The Long March 5B’s core stage has a mass of about 21.6 metric tons (23.8 tons) and measures about 98 feet (30 meters) long and 16 feet (5 meters) in diameter.

As of late Friday, the rocket was circling Earth in an orbit ranging in altitude between 92 miles and 145 miles (149-by-234 kilometers), according to U.S. military tracking data. The effects of aerodynamic drag from the upper layers of the atmosphere are gradually putting the brakes on the rocket’s velocity, which reduces the core stage’s altitude.

And the drag will only increase as the rocket gets closer to Earth. Some time Saturday or Sunday, the atmosphere will effectively capture the core stage when it no longer has the speed required to remain in orbit.

“The Long March 5B re-entry is unusual because during launch, the first stage of the rocket reached orbital velocity instead of falling downrange as is common practice,” the Aerospace Corp. said. “The empty rocket body is now in an elliptical orbit around Earth where it is being dragged toward an uncontrolled re-entry.”

The rocket will plunge back into atmosphere at nearly 17,000 mph (28,000 kilometers per hour), and most of the structure will burn up during re-entry. Friction generated from the rocket encountering air molecules will cause temperatures to build up to thousands of degrees.

But some fragments from the rocket could survive re-entry and fall back to Earth’s surface. While the rocket’s empty hydrogen and oxygen propellant tanks might burn up, denser components from the two main engines or strong pressure vessels could withstand the re-entry heating.

“The general rule of thumb is that 20–40% of the mass of a large object will reach the ground, but the exact number depends on the design of the object,” wrote Marlon Sorge, principal engineer at the Aerospace Corp.’s Center for Orbital and Re-entry Debris Studies. “In this case, we would expect about five to ten metric tons.

“Generally, for an upper stage, we see small and medium tanks survive more or less intact, and large engine components,” Sorge wrote. “The large tanks and the skin of this core stage are likely to come apart. We will also see lightweight material such as insulation fall out. The melting point of the materials used will make a difference in what remains.”

Exactly when and where the rocket will fall back into the atmosphere remained uncertain late Friday.

A forecast from the U.S. military’s 18th Space Control Squadron issued late Friday predicts the Long March 5B core stage will re-enter the atmosphere during a 12-hour period beginning around 11 p.m. EDT Saturday (0300 GMT Sunday).

The European Union’s Space Surveillance and Tracking Consortium said late Friday it expected re-entry of the Long March 5B between about 8:30 p.m. EDT Saturday and 8:30 a.m. EDT Sunday (0030-1230 GMT Sunday).

A map shows the expected ground tracks of the Long March 5B rocket’s core stage during the 12-hour re-entry window predicted by the European Union’s Space Surveillance and Tracking Consortium. Credit: EU SST Consortium

But uncontrolled re-entries are difficult to predict, and the forecast could change as ground-based radars continue tracking the Long March 5B rocket body in orbit. Changes in atmospheric drag and solar activity could move the time of re-entry earlier or later.

The error bars on the re-entry prediction will grow smaller as the time nears.

The rocket’s orbital track is inclined 41.5 degrees to the equator, meaning any debris from the rocket will fall in an area bounded by New York or Rome in the northern hemisphere, and Wellington, New Zealand, in the southern hemisphere.

“In this region, most part of the Earth surface is covered by ocean or uninhabited areas, so the statistical probability of an impact on the ground in populated areas is low,” the EU SST Consortium said. “These predictions however come with uncertainties as the object is uncontrolled, and a better estimation will only be possible a few hours before the actual re-entry.”

A one-minute error in predicting the re-entry time changes the location of potential falling debris by nearly 300 miles, or about 500 kilometers, according to the Aerospace Corp.

The consortium said the Long March 5B rocket stage is “one of the largest pieces of debris re-entering in the near past” and “deserves careful monitoring.”

“The probability that a piece of space debris will land on a city or a densely populated area is usually relatively small,” Sorge wrote. “What makes this re-entry particularly noteworthy is that it will occur between 41.5 deg N and 41.5 deg S latitudes, where the vast bulk of the world’s population lives.

“However, the statistical risk to any one person of being struck by falling space debris is so low that a colleague of mine jokes that if re-entry predictions put his house directly under the path, he’d go out with a camera and watch.”

The rocket’s plunge back to Earth this weekend is the second unguided re-entry of a massive Long March 5B core stage in less than a year.

The first launch of China’s Long March 5B rocket in May 2020 also left the core stage in orbit. The rocket dropped back into the atmosphere over the North Atlantic Ocean on May 11, 2020, minutes after a pass over the northern United States, including New York City.

Bits of wreckage from the Long March 5B rocket last year fell on Cote d’Ivoire, but no injuries were reported.

The Long March 5B core stage that re-entered the atmosphere last year was the most massive object to make an uncontrolled re-entry since the Soviet Union’s Salyut 7 space station in 1991, according to Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics who tracks global satellite and launch activity.

The Long March 5B core stage is more massive than other notable satellites that have plunged unguided back into Earth’s atmosphere in the last decade, such as China’s Tiangong 1 space lab, Russia’s failed Phobos-Grunt Mars probe, and NASA’s UARS atmospheric research satellite. It’s about one-quarter the mass of NASA’s Skylab space station, which made headlines when it fell to Earth over Australia in 1979.

Dead satellites and old rocket stages regularly re-enter the atmosphere, but re-entering objects with masses of more than a few tons are rare.

Additional Long March 5B rockets are set to launch new modules next year to assemble China’s space station. Unless China changes the design of the rocket’s core stage, there will be more uncontrolled rocket re-entry events after those missions.

Wang Wenbin, a spokesperson for the Chinese Foreign Ministry, said in a press conference Friday that it is “common practice” for upper stages of rockets to burn up while re-entering the atmosphere. He later incorrectly referred to the Long March 5B rocket body as an upper stage, and said that “most of its parts will burn up upon re-entry, making the likelihood of damage to aviation or ground facilities and activities extremely low.”

But no other launcher in the world leaves such a massive component to fall back to Earth in an uncontrolled manner.

“Controlled re-entries, particularly for a large object, require considerable planning and will have a significant impact on the design and payload capacity of the stage,” Sorge wrote. “Nevertheless, this is a preferred approach in international standards and is rapidly becoming a global norm.”

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Follow Stephen Clark on Twitter: @StephenClark1.