A Chinese rocket is returning to Earth – but we don’t know where it will land


Parts of the booster are less likely to hit populated land – much more likely to land somewhere in the ocean. But that possibility is not zero. Coincidentally: the CZ-5B booster debuted on May 5, 2020 for an expedition last year. The same problem arose again: the original booster ended up in an uncontrolled orbit before finally returning to Earth’s atmosphere. Ruins Landing in villages across the Ivory Coast. That was enough A significant rebuke from Jim Bridenstein, NASA administrator.

Now the same story is over and how hard it is to predict when and where this thing will enter because we are playing the same waiting game. The first reason is the speed of the booster: it is currently traveling at a speed of about 30,000 kilometers per hour, orbiting the planet once every 90 minutes. The second reason is related to the amount the booster has pulled. Although technically it is in space, the booster is still communicating with the upper edges of the planet’s atmosphere.

That stretch changes day by day with changes in the upper atmospheric weather, solar activity and other phenomena. In addition, the booster not only jumps around easily and punches the atmosphere cleanly – it stumbles, which makes the pull even more incredible.

Given these reasons, we can set a window for when and where we will enter the booster Earth’s atmosphere. But a few minutes or even his change could place him thousands of miles away. “Obviously it can be difficult to model, meaning we have some serious uncertainties when it comes time for space objects to reappear,” said Thomas G. Roberts, co-founder of the CSIS Aerospace Security project.

It also depends on how well the structure of the booster holds the heat generated by friction with the atmosphere. Some ingredients may hold better than others but the drugs will increase as the structure breaks down and melts. The more the structures shake, the more it will break and the more pulls will be produced, causing it to fall faster out of orbit. Some parts may hit the ground sooner or later than others.

On the morning of the rehabilitation, estimates of when it would land should have shrunk to just a few hours. Several groups around the world are tracking the booster, but most experts are using data from the U.S. Space Force. Space track Website. Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics, hopes that on the morning of the reentry, the time window will shrink to just a few hours where the booster can orbit the earth twice more. Until then, we should have a strong sense of the path that those orbits are taking and which regions of the earth may be at risk from the fountains of debris.

Space Force missile early warning systems will already detect infrared flames from a broken rocket after re-launching, so it can know where the wreckage is. Citizens may not know for a while because the information is sensitive – it will take a few hours to work through the bureaucrats before the space track site is updated. If the remnants of the booster landed in populated areas, we could already know thanks to reports published on social media.

In the 1970s, after missions these were common hazards haz “then people began to think that it was not good to read large metal parts from the sky,” McDowell said. NASA’s 77-ton Skylab space station was a wake-up call – its widely seen uncontrolled Diorbit in 199 led to massive debris in Western Australia. No one was hurt and no property was damaged, but the world was keen to avoid any risk of the spacecraft re-entering the atmosphere uncontrollably (not a problem with risky small boosters that burn safely).

As a result, after the core booster enters orbit and separates from the secondary booster and payload, many launch providers quickly burn a deorbit that returns it to the atmosphere and sets it on a controlled crash course for the ocean, eliminating the risk after it leaves space. Will. This can be accomplished exclusively by a reusable engine or a combined second engine designed for diorbit burn. The remnants of these boosters were sent to remote areas of the ocean, such as the endless region of the South Pacific, where other huge spacecraft, such as Russia’s former Mir space center, were dropped.

Another approach used by space boats during space shuttle missions and large boosters such as the Ariane 5 in Europe is to avoid placing the main stage in full orbit and to remove it as early as a few seconds while it is in Earth’s atmosphere. The smaller engines then fire the pedload to take a short extra distance of space, while the core booster is thrown into the sea.

None of these options are cheap, and they create some new risks (more engines mean more points of failure), but “they all do, because they don’t want to create this kind of wreck risk,” McDowell said. “There has been a standard practice around the world to avoid leaving this booster in orbit. The Chinese are one of its forces. “

Why? “Space protection is not just China’s priority,” Roberts said. “China has been able to avoid the consequences this weekend during several years of space launch activities under its belt, but has chosen to do so.”

Saw the last few years Lots of rocket corpses from Chinese launches that were allowed to fall to the ground again, Destroys buildings in villages and exposes people to toxic chemicals. “It’s no surprise that they’ll agree to run uncontrolled atmospheric mercenary dice, where the threat comparison for populated areas is relatively low,” Roberts said. “I find this behavior completely unacceptable, but not surprising.”

McDowell also hints at what happened during the space shuttle Colombia Disaster, when the entrance to the spacecraft becomes unstable due to damage to the wing and becomes detached. About 38,500 kilograms of debris landed in Texas and Louisiana. Large parts of the original engine ended up in a swamp – a few minutes before it broke down, parts could have hit a big city and skyrocketed, Dallas said. “I don’t think people appreciate how lucky we are that there were no casualties on the ground,” McDowell said. “We’ve been in this risky situation before and we’ve been lucky.”

But you can’t always rely on luck. The CZ-5B variant of the Long March 5B will be ready for two more launches in 2022 to help build the rest of the space station in China. There is no indication yet as to whether China plans to change the blueprint for these missions. Perhaps it will depend on what happens this weekend.



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