The fiery fate of China’s Long March 5B rocket

The core stage of China’s 100-foot (30-m) Long March 5B rocket – which launched the Tianhe space station module on April 29, 2021 – plummeted into the Indian Ocean near the Maldives late Saturday, May 8. It was one of the largest-ever pieces of space debris to make an uncontrolled re-entry back into Earth’s atmosphere. And while, luckily, there were no casualties, sightings and videos were circulating social media platforms as the rocket began its final orbits around Earth. According to China’s Manned Space Engineering Office, the country’s spaceflight agency, the core stage fell around longitude 72.47 degrees east and latitude 2.65 degrees north.

Also on May 8, new NASA Administrator Sen. Bill Nelson, who was sworn in earlier this month, released a rare statement criticizing China’s handling of the re-entry of the Long March 5B rocket:

Spacefaring nations must minimize the risks to people and property on Earth of re-entries of space objects and maximize transparency regarding those operations.

It is clear that China is failing to meet responsible standards regarding their space debris.

It is critical that China and all spacefaring nations and commercial entities act responsibly and transparently in space to ensure the safety, stability, security, and long-term sustainability of outer space activities.

Variables such as atmospheric fluctuations meant re-entry prediction windows spanned days earlier in the week, and narrowed into a two-hour window around four before expected re-entry. While most of the stage burned up, components made of heat resistant materials – such as tanks and thrusters made of stainless steel or titanium – likely made it to the ocean surface. Most returning space debris does fall into an ocean since Earth’s oceans cover 70% of our planet. In this case, the China Manned Space Engineering Office said in a post on WeChat that the rocket debris crashed to the ocean just west of the Maldives. It was unclear if any debris had landed on the atoll nation.

1/x
I updated my blogpost on the Chinese #CZ5B #reentry with a new GMAT analysis:https://t.co/MrsQ0fA1J2
I fiddled with the area-to-mass ratio in GMAT untill I got a splashdown close to the time and location reported by China. I then looked what (cont.) pic.twitter.com/5HM1ruBHVB

— Dr Marco Langbroek ? #Vaccinate (@Marco_Langbroek) May 9, 2021

On the CZ-5B core stage re-entry, I missed this interesting image before, the Italian MoD used its MFDR-LR Doppler radar to track it, and show it was tumbling…

image via @EU_SST pic.twitter.com/6eqv9r5nak

— DutchSpace (@DutchSpace) May 9, 2021

According to Mark Matney, a scientist in the Orbital Debris Program Office at NASA’s Johnson Space Center in Houston, the odds that an individual will be hit by falling space debris are one in several trillion. However, falling space debris does have the potential to create harm to property and living things.

Even for experts, plotting the precise trajectory of a large piece of falling space debris is difficult, if not impossible. There were many uncertainties involved in calculating the effect of atmospheric drag on China’s core module, for example. The high speed of the rocket body means it orbited Earth roughly every 90 minutes, and so a change of just a few minutes in re-entry time resulted in a re-entry point hundreds of miles away. Plus, the sun is now in a relatively active phase of its 11-year cycle, and Earth’s atmosphere can expand or contract with solar activity. All of these factors made it hard to estimate exactly when and where the rocket would come down.

The week leading up to the re-entry was filled with speculation on Twitter and elsewhere. Astrophysicist Jonathan McDowell of Harvard University (@planet4589 on Twitter) had been regularly tweeting about the descending core stage. In a separate statement, McDowell predicted some pieces of the rocket would survive re-entry and that it would be the:

… equivalent of a small plane crash scattered over 100 miles … Last time [China] launched a Long March 5B rocket, they ended up with big long rods of metal flying through the sky, damaging several buildings in the Ivory Coast.

Interestingly, the return of China’s Long March 5B came just days after the new Spaceflight Assets bill was affirmed by Florida’s legislature on April 26, 2021. The bill, which had the support of SpaceX, is now awaiting the signature of Florida governor Ron DeSantis. When enacted, the law will go into effect on July 1, and require that anyone who finds “reasonably identifiable” spacecraft parts – in and around Florida at least – must report them to local law enforcement and that the authorities must then make a “reasonable effort” to notify the hardware’s owner. The bill grants entities involved in launching rockets and spacecraft, such as SpaceX, access to private property, if necessary, to recover discarded space-related artifacts. Anyone failing to surrender such artifacts could be charged with “misappropriation of a spaceflight asset,” a first-degree misdemeanor, punishable by up to a year in prison or a $1,000 fine. Violators may even pay additional restitution if the hardware is lost or damaged.

Read more from EarthSky: Florida bill says companies like SpaceX retain ownership of fallen hardware

We have Salyut 7's parts for display here in Argentina.
In Oro Verde Observatory you can see part of the hatch and same electronics. The hatch is outside the main entry.https://t.co/uIhsRLPYEJ pic.twitter.com/3gZcVhQtMx

— Guillermo García (@AstroLepra) May 9, 2021

In Casilda, Santa Fe, near Rosario, my city, we have a small Salyut 7's fuel tank for display in the Museo y Archivo Histórico Municipal.
That tank fell to ground 220 km. "before" the hatch. pic.twitter.com/wWAFgMExQF

— Guillermo García (@AstroLepra) May 9, 2021

China, our world’s most populous country, hopes to have its new space station operational by 2022. The only space station currently in orbit is the International Space Station (ISS); China is not an ISS partner, and no Chinese nationals have been aboard. The Chinese government sat out the famous 1960s space race between the Soviet Union and the U.S., which ultimately launched the first humans to the moon in 1969. But, in recent years, China has been making up for lost time. It’s launched several robotic missions to the moon and Mars, as well as successfully landed on the moon’s far side, and made history with its lunar sample return mission. Tianwen-1 is a Chinese probe that entered Mars orbit on February 10, 2021; it’s set to land a rover on Mars’ surface this month or in June.

Meanwhile, the Tianhe module will become the living quarters of the future Chinese Space Station. It’s currently in its correct orbit after separating from the core stage of the rocket as planned.

Read more from EarthSky: Chinese rover Zhurong to attempt a Mars landing this month

Bottom line: China’s Long March 5B rocket – which successfully launched the Tianhe space station module on April 29, 2021 – underwent an uncontrolled re-entry back into Earth’s atmosphere, ultimately landing on May 8 in the Indian Ocean just west of the Maldives.

Via SpaceNews